# 1930's Japanese Navy - What would you have done differently?



## Garyt (Oct 30, 2014)

And this should be without the advantages of hindsight, but perhaps with the knowledge of some of the more enlightened leadership. As an example, Yammamoto was a supporter of air power and would probably like to have seen more emphasis placed on carriers than battleships.


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## tomo pauk (Oct 30, 2014)

Some of the changes would need to have the cultural changes happen before implementation. Eg. the emphasis on the trained manpower their well being - those don't grow on trees, so you better design the aircraft with a degree of protection. Rotate the crews. 
Whatever ship enemy uses, it is a target for one's submarines. Forget the 'decisive battle' - so the Yamatos don't get build, but the aircraft carriers instead. As an island nation, remember how much the German subs troubled the UK in the Great war, and act accordingly. Compare the capabilities of own AAA outfit vs. the capabiliies of own dive bombers, the result will be that something better than 25mm is needed, and in increased numbers. Radar is a mandatory item. 
It is, of course, questionable whether Japan possessed necessary resources to implement the changes - increased number of carriers also means greater number of A/C and trained crews, a possible introduction of escort carriers and other anti-sub hardware is another new drain to the resources. Some savings can be achieved via non-building the Yamatos, though.
A more capable IJN also needs more fuel, that is a major road block.


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## davebender (Oct 30, 2014)

That's what 1930s Japan needed. Not Yamato class battleships.


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## buffnut453 (Oct 30, 2014)

I'd have emigrated to San Diego. 

Just sayin'...


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## Garyt (Oct 30, 2014)

Funny, Tomo, I was going to post my answers but felt it was kind of silly to answer my own question 

But what you posted was very very similar to what I was going to post.



> design the aircraft with a degree of protection.



I'd do the same thing, but with just one issue. I thought Japanese were having problems building larger horsepower engines, so if you don't increase the horsepower and up armor the Zero for instance, do you merely have a Japanese version of something that performs like the heavier version of the Buffalo?



> So the Yamatos don't get build, but the aircraft carriers instead.



I think I read somewhere when comparing costs, you could build 2+ Shokaku's for a Yamato.



> As an island nation, remember how much the German subs troubled the UK in the Great war, and act accordingly.



Considering Japan's ability in designing torpedoes, perhaps they should have an ASW homing torpedo like the US Fido earlier. And some more advance depth charge type throwers would have been helpful, like the Hedgehog. And a convoysystem should have been used from day 1 of the war.



> compare the capabilities of own AAA outfit vs. the capabiliies of own dive bombers, the result will be that something better than 25mm is needed, and in increased numbers.



Here is where I think we have too much foresight. According to post war reports the Japanese still felt at the end of the war that their 25mm was a capable AA weapon. And I wonder how much has to do with the weapon itself - fire control may have been part of the issue, as well as the fact that Japanese AA would get lesser results as US aircraft was more durable than Japanese aircraft. And with the 25mm, it had a good muzzle velocity and cyclical rate of fire. Maybe a hopper type loading system the the 40mm Bofors could work, or even making them belt fed. But the mounts on the 25mm seemed to be a big problem, too slow to traverse and too much vibration on the triple mounts. How much of this is 20/20 hindsight I don't know.

But the 5"/50 used by destroyers was horrible for AA, and you would think that would be easy to figure out. Too slow traverse/elevation, lack of maximum elevation, very difficult to load at high angles of elevation. The fact that these were competent anti-surface weapons but struggled as AA would have been rather obvious I would think. THe problems again though seem to be as much of a mount issue as a gun issue, so fix the mounts if possible or go with the 3.9"/60 gun.



> A more capable IJN also needs more fuel, that is a major road block.



Don't know exactly what to do there, but better ASW would surely help. And I have read it was as much of insufficient refining operations as it was raw crude itself, so a little more spent on infrastructure for refineries may have helped.


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## tomo pauk (Oct 30, 2014)

Garyt said:


> ...
> Considering Japan's ability in designing torpedoes, perhaps they should have an ASW homing torpedo like the US Fido earlier. And some more advance depth charge type throwers would have been helpful, like the Hedgehog. And a convoysystem should have been used from day 1 of the war.



For the Japanese Fido to work, much more is needed than a workable 'dumb' torpedo - namely the electronics that works for the task. The eagerness to have the 'Fido-like' torp was another thing - sub hunting was not something IJN was eager to do until too late.



> Here is where I think we have too much foresight. According to post war reports the Japanese still felt at the end of the war that their 25mm was a capable AA weapon. And I wonder how much has to do with the weapon itself - fire control may have been part of the issue, as well as the fact that Japanese AA would get lesser results as US aircraft was more durable than Japanese aircraft. And with the 25mm, it had a good muzzle velocity and cyclical rate of fire. Maybe a hopper type loading system the the 40mm Bofors could work, or even making them belt fed. But the mounts on the 25mm seemed to be a big problem, too slow to traverse and too much vibration on the triple mounts. How much of this is 20/20 hindsight I don't know.



The quirk with 25mm was that it was ill able to hit a dive bomber before it was way down in the dive - the 40mm have had significantly higher effective ceiling. And an ingenious ammo loading system, if I may add.



> But the 5"/50 used by destroyers was horrible for AA, and you would think that would be easy to figure out. Too slow traverse/elevation, lack of maximum elevation, very difficult to load at high angles of elevation. The fact that these were competent anti-surface weapons but struggled as AA would have been rather obvious I would think. THe problems again though seem to be as much of a mount issue as a gun issue, so fix the mounts if possible or go with the 3.9"/60 gun.



The IJN was expecting from their destroyers to fight much more the surface targets/threats, rather than enemy A/C? They were not alone in this, of course.


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## Garyt (Oct 31, 2014)

> For the Japanese Fido to work, much more is needed than a workable 'dumb' torpedo - namely the electronics that works for the task. The eagerness to have the 'Fido-like' torp was another thing - sub hunting was not something IJN was eager to do until too late.



That's what I am talking about really, the eagerness. You would think an island nation that saw another island nation get hammered by sub warfare in WW1 would realize that threat to their own nation - and make significant efforts to shore up their ASW defenses. As they seemed to appreciate torpedoes more than any other nation you would think it would be right up their alley, IF they had the motivation.



> The IJN was expecting from their destroyers to fight much more the surface targets/threats, rather than enemy A/C? They were not alone in this, of course.



That is indeed true, and maybe even partially right, as much surface warfare was at the destroyer/light cruiser level. But still, to have a competent surface to surface weapon like the 5"/50 and to not make it a true dual purpose weapon is just gross negligence IMO. How hard would it have been to correct some of the short comings? Allow it to elevate to 75 degrees, not 55 as I think was the case in most destroyer mounts, and to not have a faster traverse/elevation speed? The Japanese had some in the Navy with good foresight as to the increasing value and lethality of aircraft. You would think they would have realized the enemy would also have a capability to sink ships by air.

As to the aircraft though, I'd at least add self sealing fuel tanks to the zero, and shorten it's phenomenal range. Great range is nice, but IMO the self fueling fuel tanks and a range more equivalent to US fighters would work fine.


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## tomo pauk (Oct 31, 2014)

Problem with Zero's tanks was that they were located in wings, and that means they were 'shallow'. Any worthwhile protection will eat up much of the volume, like it was the case for the P-39 (down from 200 in un-protected tanks to 120 gals in protected ones) or even for the P-38 (from 400 down to 300). Fuselage tanks tended to be a more 'cubic', so even once the protection was added, the decrease in capacity was maybe 10-25% at worse - like it was case for F4F (really small decrease) and P-40 (un-protected capacity was 180 gals, down to ~140 with full protection; tanks were partially in the wings).


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## Garyt (Oct 31, 2014)

Gotcha. Just as a real rough guess, what percentage of fuel do you think a true self sealing fuel tank would be lost in a Zero? Or even a Val or Kate?

I forgot to add this earlier as well, the lack of a power rammer made the 5"/50 difficult to load when the guns were trained over 45 degrees or so.

If you really think about it, the Japanese aircraft and anti aircraft put them at a huge disadvantage in the attrition you would see in Air to Ship and Ship to Air combat, exacerbating their low production of trained pilots.

Their 5" weapons were very poor AA, their capital ship mounted dual purpose weapons were better but still compared poorly to the US dual purpose weapon. The 25mm was inferior to the 40mm, And I think the Oerlikon 20mm was a fair amount better than the Japanese 25mm.

Add this to the fact that Japanese craft were lightly armored or unarmored and did not have self fueling fuel tanks.

Compound all of this later in the war with radar assisted fire and VT fuses, and there was not real comparison to the losses that would be expected by an aerial assault of enemy vessels.


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## tomo pauk (Oct 31, 2014)

The fuel capacity was about 150 us gals in the Zero (depending on the version?), radius (ie. go out vs. enemy, engage in combat, return home) is listed at 467 nautical miles (here) when carrying a drop tank. Cut the internal fuel by 1/3rd due to switch to a proper s-s tank and it is only 100 gals available of internal fuel - should make maybe 300 nmi, or almost 350 statute miles?


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## Garyt (Nov 1, 2014)

Just thought I'd add if you look at early carrier airforce vs. task force combat you will see what I find interesting results.

I'm referencing Coral Sea, Midway, Santa Cruz, the carrier engagements prior to the Guadacanal campaign which severely reduced the training level of Japanese pilots.

In these battles, even with the Zero vs Wildcat advantage in air to air combat, the Japanese suffered more severe aerial losses.

I think this would be largely a result of more effective US AA, and more fragile Japanese planes. And by "more fragile I do not mean the airframes, but things like armor and self fueling fuel tanks.


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## tomo pauk (Nov 1, 2014)

The emphasis on maneuverability, that favors a lighter aircraft, might be a result of somewhat 'romantic' look at the air combat. Namely, two aircraft are pitted one against another, no pilot is allowed to disengage (=run away) even if it can (despite the capability of the A/C). Realities of air combat were that enemy bombers need, if not outright must be downed. That requires having a strong armament, LMGs will struggle against the bombers. Also, fighters are of no use if they can't catch enemy bomber. The bomber will fight back with it's own guns - a fighter need to carry a degree of protection. When we add together those 3 requirements (need for heavy armament, protection, speed), a fighter that has all of that will not be a light one. Here is a road bump, even when the Japanese were aware of air warfare lessons from Spanish civil war, and their experiences in the war in China, that they don't have an engine powerful enough to provide for those requirements.


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## Garyt (Nov 1, 2014)

> that they don't have an engine powerful enough to provide for those requirements.



Any idea why that was? Technological issues? I've wondered that myself and never really have found an answer. Lack of motivation for building such engine perhaps?



> That requires having a strong armament, LMGs will struggle against the bombers. Also, fighters are of no use if they can't catch enemy bomber. The bomber will fight back with it's own guns - a fighter need to carry a degree of protection.



Looks like the Zero has 2 of these requirements down. We must remember the Zero was an early war plane that had to fight on through the war with little significant improvements.

The 2x 20mm + 2 x7.7 LMG are actually a pretty heavy armament for early war. Equivalent to maybe 6-7 x .50 cals if you believe the 3:1 ratio of 50's to make one 20mm. The Ammo supply was a bit low for certain, though this was at least increased from 60 to 100 per gun pretty early on. And for it's time, it was indeed a fast plane. Biggest issue is lack of self sealing tanks or armor, and this indeed was it's achilles heel. And I think it was more of an issue against bombers than fighters - you can out maneuver an opponents fighter or be tough to get a good lock on. But against a bomber you are facing and aircraft who cannot train as much firepower on you as you can on it generally, but you will usually be subject to such lighter firepower even when you have out-maneuvered the bomber. Here armor (I would think most importantly in this situation the windscreen and fuel tanks) makes a marked difference.

I'd be curious as to the amount of Zeroes shot down by strike aircraft vs the amount of US fighters shot down by strike craft in the early war. Don't count any vs. 4 engined bombers, as the Papanese did not have anything like a B-17 early on.


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## swampyankee (Nov 1, 2014)

Garyt said:


> And this should be without the advantages of hindsight, but perhaps with the knowledge of some of the more enlightened leadership. As an example, Yammamoto was a supporter of air power and would probably like to have seen more emphasis placed on carriers than battleships.



Leaving aside the best option for Japan -- which was to shoot all the right-wing loonies who were killing people who didn't want to go to war with just about anybody -- the IJN needed to improve its aviation training regimen and remember that the job of navies isn't to fight the other guy's battle line: it's to guarantee one's control of the sea. That may involve shooting up battleships, but it also involves not letting the other guy sink your merchant ships with near-impunity. The IJN was so bad at that, the Japanese Army started building escort vessels!


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## Garyt (Nov 1, 2014)

This is a bit out of the hands of the Navy, but seeing if you could get some better technology sharing with your axis ally. Like pperhaps better torpedoes for Germany, earlier and better radar for Japan.

Seems like the Allies were far better at technology sharing than the Axis, even early war when communication was easier. At least the US and GB did this very well.

For that matter, the US and GB seemed to share technology better than the Japanese Army and Navy did with each other!


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## tomo pauk (Nov 1, 2014)

Garyt said:


> Any idea why that was? Technological issues? I've wondered that myself and never really have found an answer. Lack of motivation for building such engine perhaps?



There was only one big powerful engine around, a 1500 HP Kasei when Japan was moving from from A5M and Ki-27 to the A6M and Ki-43, and that engine was to be used on the land based IJN bombers at 1st. The fighters got to be designed around the ~1000 HP engines then available, and IMo Japanese designers have done a very good job.



> Looks like the Zero has 2 of these requirements down. We must remember the Zero was an early war plane that had to fight on through the war with little significant improvements.



The IJN dropped the ball because of a too late installation of the Kinsei in the Zero, only two prototypes were built of the A6M8. They also have had the option to install the Ha-103 engine, as used on the Ki-44. 



> The 2x 20mm + 2 x7.7 LMG are actually a pretty heavy armament for early war. Equivalent to maybe 6-7 x .50 cals if you believe the 3:1 ratio of 50's to make one 20mm.



Problem was that Ki-43 (IJA, but still) never received cannons, apart from too late prototypes. Another problem was that availability of the Zero was pretty low against what the West was capable to throw in the fray. Another thing is that USN rated the Hispano, a most powerful 20 mm cannon, as equal to 3 HMGs, while the early drum fed Type 99 was of far lower MV (525 m/s vs. 880 for the Hisso II) and somewhat lower RoF than Hispano. Things got better when the 99-2 was introduced, with better MV and ammo supply, but also a lower RoF - now 480-490 rpm vs. Hispano II at 600.
It's maybe 2:1, ratio of the IJA cannon vs. .50 BMG 'kill capacity'? The Japanese batteries were of far lower weight than USA ones, of course.



> The Ammo supply was a bit low for certain, though this was at least increased from 60 to 100 per gun pretty early on. And for it's time, it was indeed a fast plane. Biggest issue is lack of self sealing tanks or armor, and this indeed was it's achilles heel. And I think it was more of an issue against bombers than fighters - you can out maneuver an opponents fighter or be tough to get a good lock on. But against a bomber you are facing and aircraft who cannot train as much firepower on you as you can on it generally, but you will usually be subject to such lighter firepower even when you have out-maneuvered the bomber. Here armor (I would think most importantly in this situation the windscreen and fuel tanks) makes a marked difference.



Against the F4F, F2A and Hurricane, it was as fast or faster, 330 mph, later maybe 350 mph. Less so against P-40, P-39, let alone P-38 or contemporary European stuff (Spitfire, Bf-109, Fw-190) it was slower. Soviets were a bit faster, too, especially the MiG 1/3. 
The lack of protection was a major shortcoming of the Japanese fighters for a good part of the war. Especially if we take as a truth that 3/4s of the fighter planes were shot down before the victim knew it is in someone's crosshairs.


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## Shortround6 (Nov 1, 2014)

Garyt said:


> Any idea why that was? Technological issues? I've wondered that myself and never really have found an answer. Lack of motivation for building such engine perhaps?



They had more powerful engines, they were just much larger and heavier. Navies refusal to allow the use of the Mitsubishi Kinsei engine is a bit harder to understand. 

The Kasei was about 400lbs heavier and 8in bigger in diameter.


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## Garyt (Nov 4, 2014)

> Things got better when the 99-2 was introduced, with better MV and ammo supply, but also a lower RoF - now 480-490 rpm vs. Hispano II at 600.
> It's maybe 2:1, ratio of the IJA cannon vs. .50 BMG 'kill capacity'? The Japanese batteries were of far lower weight than USA ones, of course.



Strictly on power, not muzzle velocity and range, I'd give even the 99-1 a 2.5:1 vs a .50 Caliber. And a 7.7mm should probably be 1/3 of a .50
overall, probably equal to the 6 x.50 arrangement on many US fighters, other than the H)-1 was not the most accurate at range.


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## Garyt (Nov 4, 2014)

BTW - Heavy Cruisers. Torpedoes or no Torpedoes? There was not going to be that huge decisive battle the Japanese had so geared up for, at least not in the way they thought it would unfold. So Torpedoes or no? I'd have to say no, other than perhaps if they really scaled back on battleships giving the heavy cruisers something for opponent's battleships to worry about is not a bad idea.

Another question too - There were 4 old battleships that did not see a ton of action, the Fuso/Yamashiro and Ise/Hyuga. I'm not sure what would be gained from scrapping them, but would that be worth it? I guess what I am asking is what could be done with the raw materials gained from scrapping these vessels?

Heck, even if you get 10 or so Destroyer Escorts for the cost of scrapping one it may not be that bad of an idea. The manpower and support costs at least would be saved.

If this is done and the Yamato's not built, you have the 4 Kongo's and the 2 Nagato's only as far as Japan's battle fleet is concerned.


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## tomo pauk (Nov 4, 2014)

Re. torpedoes on the cruisers - Japan has a shortage of destroyers vs. the USN, so leaving capable torps around could present an asset.

In case the Yamatos are cancelled, scraping the old battlewagons will put the IJN in a big disadvantage. We might want to bulk up the AAA suite, among other modifications, so those can act as bodyguard ships for 25-knot aircraft carriers? Not all of the Japanese carriers were 30+ knot machines. 



Garyt said:


> Strictly on power, not muzzle velocity and range, I'd give even the 99-1 a 2.5:1 vs a .50 Caliber. And a 7.7mm should probably be 1/3 of a .50
> overall, probably equal to the 6 x.50 arrangement on many US fighters, other than the H)-1 was not the most accurate at range.



The USN 'equation' put the Hispano's worth at 3 BMGs since the Hispano was firing not just a heavy shell, but it was fired at great MV and decent RoF. Those 3 things greatly increase the hit probability, and that also means greater kill probability. 
The 99-1 was firing a shell of about equal weight as Hispano, so it might got the same marks just based on that. It would score significantly lower than the Hispano II, though, in the USN equation.


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## Garyt (Nov 4, 2014)

> The 99-1 was firing a shell of about equal weight as Hispano, so it might got the same marks just based on that. It would score significantly lower than the Hispano II, though, in the USN equation.



Rate of fire was about 80% of the Hispano, so maybe a 2.4 or so prior to range issues. Tough to factor in the lower muzzle velocity. For contact fused HE or HEI rounds, it makes no difference for damage. It obviously effects accuracy at range, though closer it does not effect it much. Similar to the problems with the German Mk108, though it had a bigger payload and even lower velocity. The 20mm would be pretty effective against less agile bombers though.

Come to think of it, with a 60 round drum, maybe you don't want to use the 20mm cannon at range to conserve ammo. 

I'm surprised they did not replace the twin 7.7mm with a pair of 13.2mm's, these were fairly similar to the US .50. And it's only about an extra 40 pounds per gun, plus of course the ammo. Seems like it would make a lot more sense than the 7.7mm's.



> In case the Yamatos are cancelled, scraping the old battlewagons will put the IJN in a big disadvantage.



Considering there was very little battleship surface combat during the war, it would not really hurt the Japanese. Only the Kongo class saw much combat other than the Suriago straight massacre.

For the battleships to be effective as AA, there would need to be a change in doctrine, where the Japanese stay in formation to rely on AA as opposed to scurrying around to avoid being hit. I'm not sure how well the strategy would have worked for the Japanese unless they had dramatically upgraded their AA capabilities.


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## Shortround6 (Nov 4, 2014)

Garyt said:


> I'm surprised they did not replace the twin 7.7mm with a pair of 13.2mm's, these were fairly similar to the US .50. And it's only about an extra 40 pounds per gun, *plus of course the ammo*. Seems like it would make a lot more sense than the 7.7mm's.



Two things.

one, it was a question of timing. The Japanese copy of the Browning .50 wasn't ready in 1941/42.

two, the ammo is more of a problem than the gun/s. .50 cal ammo (or it's 13.2mm equivalent) weighs about 5 times what most rifle caliber mg ammo weighs. SO you have increase the gun weight by 80lbs (which does not include mounts, ammo boxes, chutes, gun heaters, etc) and 100rpg of 13.2mm ammo will weigh what the 500rpg of 7.7mm amo did. Guns run dry in about 10-12 seconds. US. 50 cal ammo weighed about 30lbs per hundred so going to 200rpg adds another 60lbs. More ammo????
The US .50 didn't like synchronization much and had a rather low rate of fire when firing through a prop. Did the Japanese fix it or just put up with it? Two 13.2s at 450-500rpm or two 7.7mms at around 800rpm?(assuming the 7.7mm guns lost about 100rpm due to the sychonization gear)


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## parsifal (Nov 5, 2014)

The thing about the Japanese procurement particualalry for the navy, is that they tended to be just a little too cute at times. often they would issue a design spec that just couldnt be met within the treaty limits, go off and design a ship that in some way or another was deficient, and then go back and have to undertake tremendously expensive fixes to try and rectify those faults.

In 1934 this faulty design and development process shot to the forefront with the capsizing of the torpedo Boat Tomodzuru, due to fudging of thge stability cals. this might work to deceive an opponent, but you cant deceive the laws of physics that dictate ship stability issues. Ships like the tomodzuru had to be basically built twice to achieve a satisfactory outcome, and this sort of thing happened repeatedly.

Getting the design right, and not trying to hide the true nature of a design, would have yielded massive resources for the Navy and army. Its not an exaggeration to claim the navy could have maintained the same force structure fopr about 30% less outlay, or convewrsely, have been 30% stronger than it was historically, if the Japanese had not tried to hide the true characterisitcs of their ships.
Thi8s was a freebie, representing no loss for the japanese fleet.

Another glaring area of wastage was in the doctrine surrounding their submarinbe fleet. The IBoats of the IJN were perhaps the most advanced submarines in the world in 1941, designed with massive endurance and a sea speed of about 24 knots. They were designed to attack the US fleet as it advanaced across the pacific, attack, then move ahead, then attack again and so on. Would have worked against the 20 knot WWI drednoughts of the pacific fleet, but against fast moving fast carrier groups, was throughly outdated. In reality the japanese should have studied the german model more closely and used their subs to attack US merchant shipping. This was the USNs achilles heel, just at it was for the Japanese. Smaller subs, better able to attack shipping should have been the way pursued by the Japanese. 

Having decided to attack the US, and build their CAGs around the Zeke, an offensive fighter if ever their was one, the Japanese needed to have ready by june 1942, an aircraft more suited to defensive operation....sacrificing range for protection and durability. They never really got to that

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## tomo pauk (Nov 5, 2014)

Garyt said:


> ...
> 
> Considering there was very little battleship surface combat during the war, it would not really hurt the Japanese. Only the Kongo class saw much combat other than the Suriago straight massacre.



Due to unavoidable battle damage, and need for modifications through war, IJN cannot expect to have all of their listed BBs available all the time. That would make 6 BBs too few for the needs of a major navy in the vast expanses of Pacific and, partly, Indian ocean. In case the IJN cannot muster BBs to support lighter surface units, Allied BBs can have a field day once encountering Japanese cruisers.



> For the battleships to be effective as AA, there would need to be a change in doctrine, where the Japanese stay in formation to rely on AA as opposed to scurrying around to avoid being hit. I'm not sure how well the strategy would have worked for the Japanese unless they had dramatically upgraded their AA capabilities.



IJN needs a change in doctrine. 
They need to forget luring the USN in a decisive battle, their subs need to go out and kill merchant ships, they need to realize that trained manpower is the greatest asset, they need to bulk up the number quality of AA suite on their ships.
IJN created a most powerful offensive naval arm in the world, so they have an idea how much the damage that can do to surface units. Expecting that USN won't make steps in similar direction is just lulling themselves in a false security.


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## Garyt (Nov 5, 2014)

Shortround6 wrote:


> US. 50 cal ammo weighed about 30lbs per hundred so going to 200rpg adds another 60lbs. More ammo????
> The US .50 didn't like synchronization much and had a rather low rate of fire when firing through a prop. Did the Japanese fix it or just put up with it? Two 13.2s at 450-500rpm or two 7.7mms at around 800rpm?(assuming the 7.7mm guns lost about 100rpm due to the sychonization gear)



I'd look at 250 rounds or so, so maybe 150 pounds extra or so including rounds and gun? As far as synchronization, the A6M5? I think it was that carried the 2 13.2mm's used wing mounted versions, even retained one of the cowl mounted 7.7 mm's.

Parsifal wrote:



> Getting the design right, and not trying to hide the true nature of a design, would have yielded massive resources for the Navy and army. Its not an exaggeration to claim the navy could have maintained the same force structure fopr about 30% less outlay, or convewrsely, have been 30% stronger than it was historically, if the Japanese had not tried to hide the true characterisitcs of their ships.
> Thi8s was a freebie, representing no loss for the japanese fleet.



Was this perhaps though experimentation, pushing the envelope and in some cases overstepping parameters? Japanese vessels always seemed
to push it to the limit as far as how much armament could be crammed on a vessel.



> Another glaring area of wastage was in the doctrine surrounding their submarinbe fleet. The IBoats of the IJN were perhaps the most advanced submarines in the world in 1941, designed with massive endurance and a sea speed of about 24 knots. They were designed to attack the US fleet as it advanaced across the pacific, attack, then move ahead, then attack again and so on.



Again, the decisive battle idea, they were looking for a revised Pacific version of Jutland, or maybe another Tsushima. Their subs had great range, speed, size, best torpedoes. They lacked in diving depth though. They would have been better to focus lees on size and more on diving depth, and of course a complete change of tactics.


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## Garyt (Nov 5, 2014)

> Due to unavoidable battle damage, and need for modifications through war, IJN cannot expect to have all of their listed BBs available all the time. That would make 6 BBs too few for the needs of a major navy in the vast expanses of Pacific and, partly, Indian ocean. In case the IJN cannot muster BBs to support lighter surface units, Allied BBs can have a field day once encountering Japanese cruisers.



I really don't think battleships were that important or that a fleet of such was needed. Now, convincing the Japanese top brass of that might be another story. If you take out Pearl Harbor, and have a US/Japan Naval conflict with the US Battleships say in early '42, and give the Japanese 2 more Shokaku class carriers, I think the battleships would be in dire straights, given the quality of the Japanese torpedo bombers and the dearth of US AA at the time. Actually, the American fleet in general would be in dire straights in this situation.

Perhaps a later war American task force with modern battleships and better AA could threaten a later war Japanese carrier force - but they would need air superiority, otherwise you have another Leyte with the roles reversed.


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## Shinpachi (Nov 5, 2014)

The battleship Yamato would be necessary at least as a symbol of IJN like a skyscraper at the time of around 1940 but Commander Nagumo for his carrier fleet. As he was an aged, conservative and stubborn navy man, he was unable to understand how to operate his air force effectively well. Win or lose, he lost not a few good chances to beat opponents fatally during the battle of Indian ocean and later in Midway. If I had been Yamamoto, I would have left the authority of command to Genda from the beginning of Pearl Harbor as he was trusted by his airmen and would not have missed any chances. Just my impression.


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## Garyt (Nov 5, 2014)

> The battleship Yamato would be necessary at least as a symbol of IJN like a skyscraper



Well, aside from the Gambier Bay, both the Yamato and the nameless skyscraper sunk the same amount of opponents surface vessels 

Genda certainly would have been a better choice, I don't know if Japanese tradition and naval tradition would allow that to be a possibility.


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## Shinpachi (Nov 5, 2014)

Any tradition is not iron rule, Garyt.


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## Garyt (Nov 5, 2014)

> Any tradition is not iron rule, Garyt.



Seems like with the Japanese Navy, tradition was pretty close to iron rule. And I'm not speaking of tactics, as you had forward thinkers like Genda and less forward thinker like Nagumo as in any other navyy.

I'm speaking more of a rigid social structure that would prevent a more junior officer from assuming command.

Not sure of the veracity of this, as it is Wikepedia, but interesting to throw into the mix IMO:



> An air power advocate from the time he attended the Japanese Naval Academy, Genda urged Japan's pre-war military leaders to stop building battleships (which he believed would be better used as "piers" or scrap iron) and concentrate on aircraft carriers, submarines, and supporting fast cruisers and destroyers. Above all, Genda thought that modern and large naval air fleet would be necessary for survival if Japan was ever to fight a war with the United States and the United Kingdom as well as their allies. However, Genda's rank—captain—was too low to be of much strategic influence.



You know Shinpachi, after reading this perhaps Genda's best role would have been as top man in the Japanese Navy. LOL


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## parsifal (Nov 5, 2014)

Garyt said:


> BTW - Heavy Cruisers. Torpedoes or no Torpedoes? There was not going to be that huge decisive battle the Japanese had so geared up for, at least not in the way they thought it would unfold. So Torpedoes or no? I'd have to say no, other than perhaps if they really scaled back on battleships giving the heavy cruisers something for opponent's battleships to worry about is not a bad idea.
> 
> Another question too - There were 4 old battleships that did not see a ton of action, the Fuso/Yamashiro and Ise/Hyuga. I'm not sure what would be gained from scrapping them, but would that be worth it? I guess what I am asking is what could be done with the raw materials gained from scrapping these vessels?
> 
> ...



This is one case where the Japanese got things absolutely right. if you look hard enough you will find a lot of statements from the allied surface admirals about how envious they were that the IJN cruisers carried TTs and they didn't. Surface battles were a very common occurrence in the pacific, more common than the carrier battles, and most often these fights were not fought at the maquis of Queensbury distances. most often they were fought at night more as bar room brawls than a distinguished duel. And in those situations the Japanese ability to fire large salvoes of Long lances made the difference. Moreover every class of warship that was big enough to do so, was given a torpedo capability. Its what made old ships like CL Nara in many respects more dangerous than most of the allied Heavy cruisers. If the Kirishima had connected with a Long Lance during the 2nd battle of guadacanal, it would have beaten two new USN BBs single handedly. TTs make that much of a difference.

Japanese moreover viewed their CLs as Destroyer leaders, rather than elements of the gunline. As gun cruisers they were pretty restricted, but as torpedo carrying leaders they were very dangerous ships .

Unquestionably, carrying torpedoes was the right decision. By the time the US fast carriers started to bite, in the latter half of 1944, it was allover anyway, and removal of the TTs in favour of more AA was a pointless and hopeless situation.

The Jap[anise did in fact get their decive battles......three times actually, and each one they lost. 

The refurbished battleships were considered the core of the battle fleet, and were not committed primarily because of fuel shortages, but even idle they served a fleet in being purpose. Sometimes you have to just pay the piper, and that's one of those situations.

Scrapping or not building battleships to ostensibly build more carriers would be a waste of resources, since the IJN never had enough planes or pilots to fully equip the carriers they had. the loss of four flat tops at midway was not really a big deal.....but the loss of 250 planes and about 130 aircrew was a crippling blow to the Japanese FAA


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## Garyt (Nov 5, 2014)

> Scrapping or not building battleships to ostensibly build more carriers would be a waste of resources, since the IJN never had enough planes or pilots to fully equip the carriers they had. the loss of four flat tops at midway was not really a big deal.....but the loss of 250 planes and about 130 aircrew was a crippling blow to the Japanese FAA



Well, putting out carriers instead of battleships also comes with the assumption of a ramped up pilot training program to be able to equip these additional carriers with trained pilots.

I've heard regarding Midway that almost as important as lost pilots were the aviation groundcrews. With Japan being not nearly as industrialized as the US, mechanics were not easy to come by. And most of these crews were lost with ships unlike the aviators, of who many escaped.

In regards to the Torpedo cruisers - yes indeed the torpedoes were a threat, but when looking at true performance as too ow many vessels were sunk by torpedoes, it seems the score is pretty close to even when looking at the amount of Japanese heavy cruisers that were sunk due to ignition of the torpedo lockers by enemy fire.

As far as the light cruisers go, yes, I'd certainly keep the torpedoes on them, and of course the destroyers as well.


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## Garyt (Nov 5, 2014)

A brief history of Japanese Cruisers having problems with their own torpedoes

6 June 1942: Mikuma is hit by bombs, fire breaks out among the torpedoes, torpedoes explode, ship sinks. (Sister Mogami, also bombed that day, has already jettisoned her torpedoes and survives.)
11 October 1942: Furutaka hit by American naval gunfire at night, fires almost immediately break out among her torpedoes, illuminating the ship, apparently drawing more gunfire. Ship is sunk.
3 April 1943: Aoba is hit by bomb from a B-17, torpedoes explode, ship is beached to avoid total loss. Later salvaged.
25 October 1944: Mogami hit by two American 8-inch shells. Fire breaks out, she collides with Nachi (her third collision of the war), then her torpedoes explode. She is bombed and torpedoed again by American aircraft, and finally must be scuttled.
25 October 1944: Suzuya is missed by bombs, but fragments from near misses ignite fires among her torpedoes, torpedoes explode, ship sinks.
25 October 1944: Abukuma is hit by 3 bombs dropped by B-24s. Fires detonate 4 Type 93 torpedoes, ship sinks.


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## Shortround6 (Nov 5, 2014)

The Japanese long lance torpedo was in a class by itself, think of it as the WW II Tomahawk cruise missile. It was part of the Japanese battle plan in a way that Allied torpedoes could never be. 

BUT to have a reasonable chance of inflicting the needed damage on the American fleet it needed to be fired in very large numbers. This means as many ships as possiable carrying and firing the max number of torpedoes. 

Quite a few ships have been lost due to their own weapons/equipment. In Fact, for battleships (including pre dreadnoughts) more battleships blew up due to their own ammo exploding in harbor than were _ever_ sunk by _gunfire only_ in action. 
Rather puts a spin on the whole worth of the battleship doesn't it


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## Shinpachi (Nov 6, 2014)

Garyt said:


> You know Shinpachi, after reading this perhaps Genda's best role would have been as top man in the Japanese Navy. LOL



I would agree with you, Garyt, if his commander had not been Nagumo but more modest guy.

That may sound realistic but there was another fact that Isoroku Yamamoto himself already broken the IJN tradition which had been built up by sons of peasants since 1872 by nominating Nagumo as the commander of the carrier fleet. Nagumo could have been a more honorable commander of the 2nd flleet for his age and career in tradition. Why not for Genda?


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## Garyt (Nov 6, 2014)

> Quite a few ships have been lost due to their own weapons/equipment. In Fact, for battleships (including pre dreadnoughts) more battleships blew up due to their own ammo exploding in harbor than were ever sunk by gunfire only in action



I'm aware of that, but the ammo for main guns was protected far better than the torpedoes and their reloads. Or at least on capital ships, destroyers had little armor. and the Japanese torpedoes were more volatile than the american torps.




> BUT to have a reasonable chance of inflicting the needed damage on the American fleet it needed to be fired in very large numbers. This means as many ships as possiable carrying and firing the max number of torpedoes.



Yeah, that decisive battle thought process. Really, I think that's one issue that hurt the Japanese was their strong focus on the decisive battle, leaving them not as flexible for other types of engagements. But indeed arming most of your vessels with torpedoes was required for this strategy.

The type 93 torpedoes were indeed very good, better range and much faster than their American counterparts. But if you look at the numbers launched, hits and damage caused, they seem to have fallen a bit short of expectations. Navweaps has an interesting article on this.


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## parsifal (Nov 6, 2014)

Any weapon system carried on ships has a risk associated with it, and the japanese, with their relatively weak Damage Control, and their emphasis on torpedo armament will inevitably suffer losses from them. Type 93s were oxygen powered and carried a warhead twice the size of most allied types, so this made them very effectiver at sinking ships. if the warhead goes off at the wrong time, its still going to do a lot of damage. but the logic "they are dangerous things, therefore they shouldnt be carried" is just so cockeyed I wonder why we are even discussing it. All weapons are dangerous. The most serious risk for carriers are fuel carried, bombs carried, and aircraft carried. Does that mean carriers should not carry bombs aircraft or fuel? A very dangerous weapon carried by Destroyers with no benefit to a surface naval battle were the ASW weapons they carried. The risk to ships that carried them was very great. In 1939 Ive just finished writing up an account of a British DD, where the holding straps for the DCs came loose, allowing one of the DCs to roll off the stern and explode under the ship, The heaving effect from the detonation caused another two DCs to break free and also explode, almost causing the stern to blow off. Not only that but two other ships nearby also very extensively damaged. On the basis of the arguments being presented here, that means that British DDs were faulty because they carried DCs. Its a totally non-sequita argument, buts its a headline grabber because it looks cute.

Another example of how dangerous own weappon systems can be are mines. The stories of own losses to these weapons are prodigious, but it would be foolhardy to argue that because they are dangerous to own forces, they ought not be used. The best example of their danger in my opinion was the loss of the French ML Cruiser Pluton in 1939. Not only was the ship itesl lost whilst alongside in Casablanca, eight other warships were lost from the explpoding mines. by the logic here, the French should have scrapped all their mine stocks and ceased laying mines. In one month alone, October 1939, mines accounted for the loss of 3 of the 5 Uboats sunk to that point in the war......but without mines there would have been no such losses. Friendly fire is a fact of life, and LL are no exceptions, but neither are they an unnaccepotable risk, given thge benefits they confe4rred. 

What isnt brought out are the intangible benefits brought about by Japanese Torpedo techs. Ive read in various accounts that the fear of Long Lance probably lengethened the war by over a year......thats 25% of Japanese resistance capability denied at a stroke. Further, some of their best efforts in air attacks came from their air launched torpedoes, which benefitted greatly by the efforts put into the Long Lance torpedoes. japanese contact pistols and casings as well drive mechanisms and gyro systems were reliable, accurate, strong. Whereas US topedoes required a launch speed of around 90 knots and a drop height not exceeding 60 feet (it got a bit better later on) for a percentage chance of a true run of about 40%, Japanese air launched torpedoes could be launched at 350 knots from drop heights of up to 250 feet, and still have about a 90% chance of running true. These torps used the same depth keeping, casing design etc as the LL. Take away the LL development, and you lose all that.

As far as the argument that the Japanese should abandon half its battlefleet in favour of carriers, and at the same time wave its magic wand to increase pilot outputs. Well for the latter part of the war, that holds true, but in the context of the 1930s, it was simply beyond the Japanese capability to do this. Both the IJN and the USN spent the entire lead up for war preparing for a jutland style decisive battle, the so called Mahanist battles (an American it ought to be pointed out). The US Pacific Fleet was at Pearl Harbour 7th December 1941, for precisely the reason of implementing its Plan Orange strategy....an advance across the Pacific with Battleships the focus. It only abandoned the strategy because the losses at PH forced it to. Nobody expected the makeshift hit and run carrier attacks to work as well as they did.

For the Japanese, faced with severe treaty limits that more or less guranteed US superiority of numbers, and placed very severe restrictions, by category, reducing the battleship numbers is akin to tying another arm behind your back. Scrapping a battleship doesnt mean in the early 1930s that you can build carriers in their place....it just means you have less battleships. On December 29, 1934, the Japanese government gave formal notice that it intended to terminate the treaty. Its provisions remained in force until the end of 1936 and were not renewed. Japan effectively ignored the treaty from the end of 1936 and began to benefit materially from that walk out from roughly 1938. Thats not a lot of time to benefit from a scrapped battlefleet. Certainly not enough time to significantly alrter or improve the carrier numbers or more importantly aircrew numbers

Japans solution to the treaty limits placed on her was to maximise quality. She knew that every ship, every aircraft, every torpedo, had to 3/2 times better than the US material, or better, and she set down the path that entailed. She had probably achieved that advantage by December 1941. She was correct to follow the idea of seeking the decisive battle pre-December 1941, because that was the only way she could hope to defeat the US....a short sharp shock and awe war, which incidentally wasa the same war the US wanted to fight


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## Garyt (Nov 6, 2014)

> The Jap[anise did in fact get their decive battles......three times actually, and each one they lost.



Indeed they did, Parsifal, but none turned out to be anything like the planned surface vs surface engagements.

If you are looking at Midway, Philipine Sea and Leyte Gulf as the 3 major engagements, None of them other than Leyte had any real type of surface to surface action. And at Leyte, the Japanese airpower was non-existent which made the Japanese fleet target practice for US strike aircraft. Never once was there the decisive surface to surface action that was looked for. 

Of course the main reason behind this was that between roughly 1930 and the 1940's, airpower had become the deciding factor. And really when the plan for a decisive battle was influencing the design of the fleet, the carrier planes were light and of not much threat to armored surface vessels. And pretty well every navy around the world had aircraft carriers thought of as scouts at this time. I guess one could think they should have realized planes would get bigger, stronger, faster, and more of a threat, but on other coutry really thought this way around 1930.
I think what made a huge difference is that with America's industrial base, they were able to react quicker and in more force with both new ships and changing existing ships to adapt more to the carrier style of naval combat.


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## Garyt (Nov 6, 2014)

Parsifal, I am not by any means stating the Japanese should have given up on or not researched or not equipped their ships with the long lance. BUT what I am questioning is whether they should have been deployed on cruisers, particularly heavy cruisers. If you look at kills vs. being killed, the use of long lances on Heavy cruisers did not seem to make much sense. On Destroyers and light cruisers - absolutely. I just question the idea of arming your heavy cruisers that way. 

I understand the why - the decisive battle launch of 100's upon hundreds of torpedoes, at night I think the plan was, by cruisers and destroyers to weaken the american battle line for a daylight gun engagement. But perhaps the Japanese would have fared better by following the American plan of no torpedoes aboard heavy cruisers.


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## Shortround6 (Nov 6, 2014)

The difference between the Japanese and the Americans was that the Japanese _planned_ to fire the Long Lance torpedoes from beyond gun range or at least very early in the gun gun dual between surface ships, minimizing the danger of taking a hit to the torpedoes. The Shorter range of the American torpedoes meant that they stood a good chance of taking gun hits _before_ getting into torpedo range and getting rid of them. 

Most of you examples of ships being lost to their own torpedoes are from aircraft bombs which weren't anywhere near the threat in the late 20s/early 30s when the Japanese Cruisers were designed and built.


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## Garyt (Nov 6, 2014)

> Most of you examples of ships being lost to their own torpedoes are from aircraft bombs which weren't anywhere near the threat in the late 20s/early 30s when the Japanese Cruisers were designed and built.



Indeed. But it's not extremely difficult to retool once you realize the threat that aircraft poses by about 1940. Get rid of some torpedo tubes, add some AA.

Shortround, what I am trying to point out is that Japan geared it's navy almost entirely to fight that decisive surface battle which never materialized, certainly not in the way envisioned by the Japanese. By building their navy with such single minded purpose, they made it less effective and/or versatile for engagements that did not take place in the way the decisive battle was envisioned.


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## parsifal (Nov 7, 2014)

Garyt said:


> Parsifal, I am not by any means stating the Japanese should have given up on or not researched or not equipped their ships with the long lance. BUT what I am questioning is whether they should have been deployed on cruisers, particularly heavy cruisers. If you look at kills vs. being killed, the use of long lances on Heavy cruisers did not seem to make much sense. On Destroyers and light cruisers - absolutely. I just question the idea of arming your heavy cruisers that way.
> 
> I understand the why - the decisive battle launch of 100's upon hundreds of torpedoes, at night I think the plan was, by cruisers and destroyers to weaken the american battle line for a daylight gun engagement. But perhaps the Japanese would have fared better by following the American plan of no torpedoes aboard heavy cruisers.




The trouble is your not understanding the why. The decisive battle did not play out as a single decisive event, but rather it played out as a series of drawn out affairs, which in the end favoured the Americans and their vastly superior resources. But at a tactical level, the Japanese got the best of most of the surface actions until well into 1943, with one or two exceptions. Its just that the US could afford to take their losses and step right back up for more, the japanese could not. Therein lies the reasons for the Japanese defeat...simple sheer attrition. it had nothing to do with their cruisers carrying torps. if anything the carrying of TTs by all capital ships was part of the secret to Japanese success.

Why was it that the Japanese could achieve victory in most of the surface actions they fought. Consistently they were outnumbered, they were certainly behind the USN in terms of major technologies like radar, Japanese gunnery was patchy at best, and their torpedoes missed more often than they hit. Given all that, one wonders how they survived even the first year of the war, let alone emerge as the tactical victors. The answer lies in one word....flexibility.

For the Americans with certain ships only equipped to do certain things seems like a dreadnoughtish (with its all or nothing principals considered) thing to do, but in the confusion of a night battle this was a massive handicap. In night battles it always was the Torps that delivered the fatal blows, or almost always. Separate the US cruisers from their escort and they are vulnerable. And separate they did....often. This made them far less capable than their japanese counterparts. The Japanese cruisers, by camparison were packing their own heat and this always meant they were dangerous, with or without their destroyer escorts. It meant japanese DDs could detach from protecting their gunlines and move in for close range attacks, sometthing the US could only do if they accepted massive risks to their gunlines.

So it was absolutely essential that Japanese cruisers carry torpedo armament, to maximise the flexibility of the force of cruisers and destroyers. Their equipment with flashless powder, their disdain in using TBS, whilst the US ships chattered incessantly, the ability to react immediately without orders, or trying to worry about "co-ordination" like the Americans always had to do, made them very dangerous at night. For the light cruisers in particular, their ability to fire torpedoes and outrange the US DDs gave their destroyers a massive advantage in firepower over the US light forces. US CLs were completely unable to undertake the same mission, though they did try. Mostly US cruisers acted as targets that the japanese shot at , whilst the US destroyers did their best to work into position and do some real damage with their vastly inferior torpedoes. Post Guadacanal, the USN did a study into its cruiser fire capabilities and found them to be very nearly useless in the close range brawls that were the night fights in the Solomons. ROF for the cruisers were too slow to track and hit fast moving targets , their radar could not track quick enough and was frequently inneffective. Procedures too slow and cumbersome. It took another year for the USN to finally work out procedures that could get the better of the japanese in a one on one fight for their cruisers. 

You have a vastly over-inflated view of US effectiveness in surface actions in 1942. They had one or two very significant wins, and full credit needs to be given for that, but to argue that the Japanese should abandon a very successful formula and adopt a known less effective formula makes no sense to me at all.


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## Garyt (Nov 7, 2014)

Parsifal, are you familiar wit this article? Were the Best Good Enough?

It goes into depth battle by battle, how many torpedoes were launched, what the effects were, etc.

If we look at it as a strict scorecard, Japanese CA's lost due to their torpedoes exploding, and factor in how many allied vesseld were sunk by cruiser torpedoes (this would be rough, all we could do is take total torps fired vs. those fired by cruisers and apply that percentage to american losses by Japanes torpedoes), and I think the results would be more Japanese CA's were sunk because of their torpedoes than by their torpedoes.

And to be fair, we should throw out sinking of vessels that were ready to be scuttled, as well as heavy cruisers which were heavily damaged prior to their torpedoes going off.

Now perhaps you believe that there are reason beyond the results that justify Japanese CA's carrying torpedoes. Possibly, but I still think it should show in the results.


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## tomo pauk (Nov 7, 2014)

Hmm - how many Allied ships were sunk by gunfire vs. how much by the torpedoes, by the Japanese surface units (minus CV)?


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## Garyt (Nov 7, 2014)

Gambier Bay	25 October 1944	Sunk by Japanese naval gunfire
Heavy cruisers[edit]
Name	Date	Cause
Astoria
9 August 1942	Sunk by naval gunfire
Houston
1 March 1942	Sunk by naval gunfire and torpedoes
Northampton
30 November 1942	Sunk by naval torpedoes
Quincy
9 August 1942	Sunk by naval gunfire and torpedoes
Vincennes
9 August 1942	Sunk by naval gunfire and torpedoes
Light cruisers[edit]
Name	Date	Cause
Atlanta
13 November 1942	Sunk by naval gunfire
Helena
6 July 1943	Sunk by naval gunfire (torpedoes)
Destroyers[edit]
Name	Date	Cause
Barton
13 November 1942	Torpedoed by Japanese destroyer Amatsukaze

Benham
15 November 1942	Scuttled after being severely damaged by Japanese torpedo
Blue
22 August 1942	Torpedoed by Japanese destroyer Kawakaze

Chevalier
6 October 1943	Scuttled after being severely damaged by Japanese torpedo
Cooper
3 December 1944	Torpedoed by the Japanese destroyer Take

Cushing
13 November 1942	Sunk by naval gunfire
Duncan
12 October 1942	Sunk by naval gunfire
Edsall
1 March 1942	Sunk by naval gunfire and carrier-based aircraft bombs
Gwin
13 July 1943	Sunk by Japanese torpedoes
Henley
3 October 1943	Sunk by torpedoes
Hoel
25 October 1944	Sunk by naval gunfire
Johnston
25 October 1944	Sunk by naval gunfire
Laffey
13 November 1942	Sunk by naval gunfire
Monssen
13 November 1942	Sunk by naval gunfire
Pillsbury
1 March 1942	Sank in surface action with Japanese cruisers Takao and Atago

Preston
15 November 1942	Sunk by naval gunfire by Japanese cruiser Nagara

Walke
15 November 1942	Sunk by naval gunfire


From the above list, looks like 14 by gunfire, 4 by a combination of gunfire and torpedoes, and 8 by torpedo. I've counted destroyers and larger, combatants only, and tried to remove any that were sunk by airpower, subs, or not in the Pacific theatre. The only thing I'm not sure of, and you would have to research this vessel by vessel, is if any of these destroyed by gunfire and torpedo were given the coup-de-grace by a torpedo, the real damage coming from gunfire. There may not be any.

Next question would be how many were destroyed by torpedoes from heavy cruisers? Not sure, but it would be in the minority for certain. It seems when a ship is listed as doing the sinking, it is almost always a destroyer.


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## gjs238 (Nov 7, 2014)

Some of this may be difficult to quantify if the Wikipedia article on the Type 93 "Long Lance" torpedo is correct:

https://en.wikipedia.org/wiki/Type_93_torpedo

_In the early surface battles of 1942–43, Japanese destroyers and cruisers were able to launch their torpedoes from about 20 km (11 nmi; 12 mi) at the unsuspecting Allied warships attempting to close to gun range. Allied warships expected that, if torpedoes were used, they would be fired from not more than 10 km (5.4 nmi; 6.2 mi), their own typical torpedo range. The many torpedo hits suffered by Allied warships in such engagements led their officers to believe torpedoes had been fired by undetected Japanese submarines operating in concert with the surface warships. On rare occasions stray very long-range Type 93s struck ships much further range than their intended targets, leading the Allies on occasion to suspect their ships had been mined. The capabilities of the Type 93 went mostly unrecognized by the Allies until examples were captured intact in 1943._


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## Garyt (Nov 7, 2014)

I think the range of the Long Lance was a bit overrated as far as it's sucess. It could give you the rare hit at extreme range, which would be a suprise to allied forces in the early part of the war, put I believe other factors, speed and reliability were more important.

In an excerpt from an article by Joseph Czarnecki regarding the type 93 torpedo:



> The first is a review of the Type 93 torpedo by range fired, and speed setting employed. The dismal performance in such long-range actions as Java Sea and Komandorski Islands, and the relative success in the close-range actions of the Solomons Campaign, imply that the weapon’s speed was a greater asset than its range. It may be that the Japanese misappreciated their own weapon and would have been better served by a plan which eschewed “long-range concealed firing” in favor of short-range attacks that offered the enemy less time to evade.


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## tomo pauk (Nov 7, 2014)

Garyt said:


> ...
> 
> From the above list, looks like 14 by gunfire, 4 by a combination of gunfire and torpedoes, and 8 by torpedo. I've counted destroyers and larger, combatants only, and tried to remove any that were sunk by airpower, subs, or not in the Pacific theatre. The only thing I'm not sure of, and you would have to research this vessel by vessel, is if any of these destroyed by gunfire and torpedo were given the coup-de-grace by a torpedo, the real damage coming from gunfire. There may not be any.
> 
> Next question would be how many were destroyed by torpedoes from heavy cruisers? Not sure, but it would be in the minority for certain. It seems when a ship is listed as doing the sinking, it is almost always a destroyer.



Thanks for the effort to type down the list. The link you kindly provided lists 18 Allied ships sunk by a torpedo, though. More Allied ships were also lost by gunfire, too, ie. not just USN ships.


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## Garyt (Nov 7, 2014)

> The link you kindly provided lists 18 Allied ships sunk by a torpedo, though



That's why I only included combatant types. I mean an LST may carry some light AA, but it's not a combat vessel.

Parsifal's thoughts seemed to be by putting type 93's on a CA you are making them more effective in a battle setting, so I look to combat vessels sunk.

Against a slower badly armed and armored non-combatant vessel, you can really sink it with anything, it's your choice. That's one major reason why subs carried deck guns, they could sink weaker opponents without wasting valuable torpedoes. 

As far as coming up with a list of all allied ships sunk, it would have taken a heck lot more work. And the US vessels sunk should provide a decent enough sized sample base to get an idea.

Also, I did not count aerial launched torpedoes in the equation - it's apples and oranges.


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## Glider (Nov 8, 2014)

I am more or less out of the loop at the moment due to work but I am surprised that no one seems to have suggested buying the 40mm AA gun, being up to speed on radar development and deployment, plus developing a larger and more modern anti submarine capability. These to a larger degree, were what killed the Japanese forces. As with the Luftwaffe the Japanese air forces should have put more effort into getting their training programs into full gear earlier.

There was nothing wrong with the aircraft of the IJN apart from being a little slow on introducing a follow on to the Zero and the ships were very capable.

Had the IJN carriers been fitted with Radar then the Battle of Midway would almost certainly been won by the Japanese and the impact of that would have been huge. The 25mm wasn't as bad as most people think but there is no doubt that the 40mm would have made their AA defences far more dangerous. 

As for the need for better A/S defences need I say anything as its so obvious. Japan is an island as is the UK and they should have put as much effort into A/S equipment, training and infrastructure as the RN did.


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## parsifal (Nov 8, 2014)

This is a very suspect way of assessing the effect of Long lance on the battler. A better way would be to look at one battle where Japanese cruisers were alone or nearly alone, and assess the performance in that situation. A near perfect battle exists for that very purpose

Savo Island

Admittedly there were a lot of other factors at work that caused the allies to get themselves defeated, but its significant to note that the Japanese cruisers of which there were 5 CAs and 2 CLs were escorted by a single DD. An allied force in that situation could not have operated. as it was the Allied force, some 9 cruisers (in the total force, with 6 actually engaged) and 15 DDs failed to co-ordinate. The Japanese were completely impervious to the allied destroyers, who fired salvo after salvo of torpedoes at them but at long range. The US DDs milled around aimlessly a lot, but also, they could not risk getting close to the Japanese because they feared the torpedo broadsides carried by the Japanese cruisers. Not so the Japanese cruisers, who closed on the US and Australian cruisers to point blank range and then tore them to pieces with guns and torps. The torps made all the difference. The Allies lost 3 cruisers on the night, plus two DDs heavily damaged, and a further cruiser scuttled the next day. all of the cruisers had suffered damage either directly or indirectly because of the Long Lances on the cruisers, and could not reciprocate, at least partly, because they could not co-ordinate with their own DDs and could not risk getting too close to the IJN because of the fear of the IJN torpedo broadsides. Not that they knew exactly what was going on. Not all of these losses can be attributed solely to Japanese topedoes, but the torpedoes were part of a weapon system, and that weapon system delivered repeated tactical victories for the japanese, and made the achievement of a strategic victory at guadacanal much more difficult. After Savo, the USN avoided resupply of the island except by day, and that strung the campaign out by many months, because the control of the seas, the key to everything, was passed to the IJN at night....all because of the fear of the torpedoes the Japanese ships carried, which included their heavy ships. . The same situation arose at New Georgia. At bougainville the USN were at last able to hit back on better than even terms. All this fuss was largely due to to the Long lance effect. Without it, the Japanese would have been far more manageable at night, and a big part of that threat arose because their cruisers were torpedo armed and the Allied cruisers were not.


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## tomo pauk (Nov 8, 2014)

Broadly related to the thread - a historical research of the USN in ww2, so it would include the INJ assets actions: link.


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## Shortround6 (Nov 8, 2014)

I would note that the Americans were about the ONLY navy not to put torpedoes on heavy or large cruisers. Now maybe the US was right and everybody else wrong but the Japanese were not following a path all on their own. 

_FEAR_ of the torpedo has often exceeded it's combat results in surface actions. 

And _HOPES_ of results from the torpedo have often exceeded it's actual results/effects. 

Japanese faith/hope in the Torpedo got back the Russo-Japanese War of 1904 when they achieved some spectacular success with the primitive torpedoes of the day and in the 1920s/30s when the Japanese cruisers were built those successes were only 25-30 years old.


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## Garyt (Nov 8, 2014)

> FEAR of the torpedo has often exceeded it's combat results in surface actions.
> 
> And HOPES of results from the torpedo have often exceeded it's actual results/effects



Definitely.

Parsifal, you bring up some good points about Savo, most notably that I see a force of mostly cruisers was able to do some damage with torpedoes.

As far as the fear of torpedoes keeping US destroyers at bay - I don't think this was the case. I think the US destroyers milling about has much to do with surprise, a lack of co-ordination, and that the US was not trained to night operations nearly as well as the Japanese, which is the reason for the first two issues in this sentence.

I'd say Savo did however show the superiority of the Japanese torpedo over the US torpedo at this stage of the war, but in general I'd say the sucess in night battles had more to do with two factors, the superiority of the Japanese torpedoes and better Japanese night training than it did Japanese heavy cruisers being torpedo armed. Radar assisted fire control helped turn the tide for certain later on.

I'd also not try to put hindsight in the hands of US destroyer captains - the US sailor was not fully or even close to fully aware of the specifics of the type 93, or the inadequacies of their own torpedoes by comparison. Some of the long range early war strikes by type 93's were often thought to be submarine torpedoes or even mines. The boat captains in WW2 did not have our advantages of post war knowledge of weapon systems. It would be a confusing situation for them at best at night, and knowing where the torpedo came from that it them was very much a guesstimate.

Shortround, It does indeed look like many heavy cruisers of other navies carried torpedoes as well. Looks like the Zara class, the most modern Italian class bythe start of Ww2 was not torpedo equipped. The British have some with and some without, and all German Heavy cruisers carried torpedoes. What does seem to be the trend though is that the newer the cruiser, the more likely the torps are not carried.

The difference though is these nations torpedoes were not nearly as dangerous for the user as the type 93. Chokai was hit by a single 5 inch shell which set of it's torpedoes. This type of shell should not have done much damage, and with less volatile torpedoes, it would have been OK as well. Destroyers really have no armor, which means their magazines are not protected, to the torpedo provides no more threat really than it's existing magazines already do. With a cruiser, with a few inches of belt and deck armor, you are somewhat impervious to 5" shells, HE rounds are not a huge threat, you even have protection from 6" rounds at a portion of distances.

With torpedoes on deck, you in essence have brought some of your magazines up above the armor protection, making you vulnerable to rounds which would not normally penetrate your armor. I also makes you vulnerable to GP bombs, the type most carried by aircraft. A GP bomb may still cause damage, but is not going to generally penetrate the armor of many cruisers, keeping it away from the magazines. Again, with torpedoes on deck, it's like having your magazines on deck.

I'd think even putting less volatile torpedoes on deck would be a more viable option. The Japanese had a type 96 torpedo used in subs that seemed to perform pretty well, and was a 36% oxygen mixture, not pure oxygen. I would think this would be a fair amount less volatile than the 100% oxygen used in the type 93. I think what is important there were a few aspects of the type 93 that made it better than the US torps, perhaps most importantly was that it had a much more reliable detonation system.


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## parsifal (Nov 8, 2014)

Ah no, the USN by August 1942 had had at least several scraps with Long Lance, and had a good understanding of its capabilities. The first big scrap had occurred at java sea, in which US DDs and a cruiser had participated. They again were subjected to its capabilities on several of the subsequent engagements, including Sunda Strait, where they lost a cruiser.

USN DDs did fail to react adequately at Savo, and a lot of that was to do with their inability to co-ordinate . This happened repeatedly in the coming night battles. A lot of it was to do with the lack of training and faulty procedures. USN reactions in night battles was a confusing array of chatter across TBS, blinding flashes and confused situational awareness, that inevitably led to fatal hesitation. US procedures might not have meant to do this, but in practice it did.....they confused the hell out of themselves and paid heavily repeatedly. Until USN DDs detached themselves from protecting the US cruisers, they were doomed to that sort of second rate response. Invariably they were tied to protecting cruisers and never got the chance to shine in their own right until much later. The lack of torpedo armament in the US cruisers undoubtedly was a factor in this lacklustre performance for its destroyers...the cruisers were chained to them like a dead albatross around their necks. Inevitably the Destroyers were always confused, because they had to watch two games at the same time....what their own cruisers were doing and what the opponents were doing. inevitably they got lost and confused and they hesitated too often, sometimes because they were forced to remain too close to their own cruisers and coulod determine who they were firing at. 

Eventually some people in the USN began to realize that the cruisers they were chained to were not worth the trouble. It is significant that the real turn for the USN in these battles came with a man called Arleigh Burke. Ive often said that Burke was in the wrong navy, because he sure acted like a Japanese Admiral. After one of the 30 or so battles fought near Bougainville, he once stated that the difference between a bad admiral and a good admiral in a battle at night was about 10 seconds...referring to his now standing orders to immediately attack, with both guns and torpedoes, and use maximum speed. He was given the nickname 31 knot Burke, because he was unhappy with that speed....his usual; attack speed was 35 knots...flat out and not waiting for any torpedo-less cruiser to confuse the hell out of him and more to the point, not having to wait for orders to engage, which was invariably the case when a mixed force of cruisers being protected by Destroyers was involved. Most of Burkes battles were fought without cruisers to "support" him. The Americans were finally learning, and I bet they wished all their ships had torpedoes by that stage. They eventually learned to do without them, by very intensive training, a change in tactics and heavy use of radar guided control. They had the numbers by then, but could have been a whole lot easier if they had equipped their ships at the outset with torpedoes that worked and fitted them to all ships they intended to use at night


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## Garyt (Nov 8, 2014)

> Ah no, the USN by August 1942 had had at least several scraps with Long Lance, and had a good understanding of its capabilities.



Having good ideas of the capabilities of the long Lance runs contrary to most of what I have read. Indeed they fought of Java Sea, but as I mentioned they were not even sure what hit them, attributing some of the long range hits to a submarine or even a mine.

From the Pacific War online Encyclodedia:



> Because of the long range and nearly invisible wake of the Long Lance, its existence remained a secret well into the war. Hits from the Long Lance were often attributed to mines or an undiscovered submarine. It took the capture of Japanese documents to convince Allied naval leaders that the Japanese had come up with such a capable weapon. An intelligence bulletin accurately describing its performance was not issued until March 1944.



I'm not sure of the quality of the Pacific War Encyclopedia, but I must say it meshes with most of what else I have read of the type 93 torpedo. And the intelligence bulletin regarding it not coming out until 3/44 would seem to coincide with this as well.


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## Shortround6 (Nov 8, 2014)

Garyt said:


> Shortround, It does indeed look like many heavy cruisers of other navies carried torpedoes as well. Looks like the Zara class, the most modern Italian class bythe start of Ww2 was not torpedo equipped. The British have some with and some without, and all German Heavy cruisers carried torpedoes. What does seem to be the trend though is that the newer the cruiser, the more likely the torps are not carried.



In many cases the torpedoes were there in the initial planes but dropped due to weight problems. It is a lot easier to NOT install the tubes than it is to change the thickness of deck armor or redesign turrets or whatever else they thought they needed to do to get the weights in line. Most 8in gun cruisers built between the wars were _very_ tight ships from a weight standpoint. And weight high up causes problems that magnify. Most countries cheated to a greater or lesser extent on the weight and still couldn't get everything wanted in one ship. Once you had built the hull (even if not launched yet) major changes in armament (like more AA guns) have to be compensated for by taking something else off the ship. 



> With torpedoes on deck, you in essence have brought some of your magazines up above the armor protection, making you vulnerable to rounds which would not normally penetrate your armor. I also makes you vulnerable to GP bombs, the type most carried by aircraft. A GP bomb may still cause damage, but is not going to generally penetrate the armor of many cruisers, keeping it away from the magazines. Again, with torpedoes on deck, it's like having your magazines on deck.



While the GP bombs _might_ not kill/sink a cruiser (and many cruisers had fairly thin deck armor over large parts of the hull.) depending on where they hit they it might only take one "mission" kill a cruiser, make it unable to continue on its mission. Fire control and some other systems being more vulnerable to damage than is generally thought. Bombs have taken out condensers, and boiler rooms without actual penetration of the space. 

Naval damage is very hard to "model" or war game because so much depended on "luck". Where do the first few hits happen and what effect do they have. If one ship looses it's fire control in the first 2-3 hits that skews the rest of the battle, but another ship might take many hits before it's fire control is taken out.


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## Garyt (Nov 8, 2014)

> depending on where they hit they it might only take one "mission" kill a cruiser, make it unable to continue on its mission.



I agree. But something like taking out fire control requires a very lucky hit - with the area occupied by torpedoes a bomb hit would not have to be that "lucky", as anything amid ships stood a good chance of getting to the torpedoes, even more so if as volatile as the type 93. And secondary fire control systems were usually available, so it usually would not "mission kill" a capital ship wit one director being taken out, though the using the secondaries usually meant a bit less accuracy. Heck, you could even uselocal control but then accuracy would indeed be compromised, unless at very short range.



> (and many cruisers had fairly thin deck armor over large parts of the hull.)



Indeed. And some, including many Japanese cruisers had rather thin armor over the turrets. But about all US and Japanese Heavy Cruisers had at least 2 inches or more over the magazines, which would certainly be enough to stop penetration. And even those with thin turret armor (only an inch or so on some Japanese CA's) still had the 2"+ deck armor, which had to be penetrated to reach the magazines. 



> Bombs have taken out condensers, and boiler rooms without actual penetration of the space.



Yep, even the Musahi had a boiler room taken out by a bomb, and no bomb used on her was capable of penetrating her massive deck armor. Had to be scaling or something similar. Maybe even a luck hit at a joint or even down the smokestack, though nothing indicates that. I guess if you hit a ship with 27 bombs, a few will be lucky hits 

But still, a non penetrating hit was far far less likely to cause damage beneath a layer of armor as opposed to a penetrating hit.


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## parsifal (Nov 8, 2014)

Garyt said:


> Having good ideas of the capabilities of the long Lance runs contrary to most of what I have read. Indeed they fought of Java Sea, but as I mentioned they were not even sure what hit them, attributing some of the long range hits to a submarine or even a mine.
> 
> From the Pacific War online Encyclodedia:
> 
> ...



The USN had knowledge about Long lance from at least 1935. I refer you to the USN Intel report referenced DOD.DIR.5200.IO. This was an open file on Japanese torpedo technologies, begun in 1935 and updated periodically (and regualalry) thereafter until the final report in early 1946. The final report is dated january 1946, but it was a living document, showing that the USN had an interest in this technology from at least 1935, and documents LL development from around 1920. Both the USN and the RN tried to develop oxygen fuelled torpedo engines but abandoned them over safety concerns. They also believed prewar that the weight and reduced torpedo broadsides were an overall liability, along with the notion that the oxygen propellant was a liability. This argument is far from a new idea. After March 1942, that line of argument completely disappear from the intelligence assessments...the USN knew these weapons were lethal additions to the Japanese inventory, and those intelligence summaries tells it all.

So the intelligence was there....it just wasnt acted upon. USN surface admirals were amongst the most reactionary in the world, almost impervious to any sort of change that might challenge their view on how a naval battle ought to be fought. So in a sense what you are claiming (that the USN was unaware of the LL lethality) is true. Not because they didnt know about it, but because they chose not to know....the official record shows that they clearly had access to such information as was needed....., put most simply they didnt act on this information because their concepts were so entrenched and they (the US surface admirals) so unmovable to change that they simply ignored the threat. The result was that their surface fleet , despite the knowledge being there, chose to ride into battle unprepared for the carnage about to be unleashed on them.

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## swampyankee (Nov 9, 2014)

parsifal said:


> The USN had knowledge about Long lance from at least 1935. I refer you to the USN Intel report referenced DOD.DIR.5200.IO. This was an open file on Japanese torpedo technologies, begun in 1935 and updated periodically (and regualalry) thereafter until the final report in early 1946. The final report is dated january 1946, but it was a living document, showing that the USN had an interest in this technology from at least 1935, and documents LL development from around 1920. Both the USN and the RN tried to develop oxygen fuelled torpedo engines but abandoned them over safety concerns. They also believed prewar that the weight and reduced torpedo broadsides were an overall liability, along with the notion that the oxygen propellant was a liability. This argument is far from a new idea. After March 1942, that line of argument completely disappear from the intelligence assessments...the USN knew these weapons were lethal additions to the Japanese inventory, and those intelligence summaries tells it all.
> 
> So the intelligence was there....it just wasnt acted upon. USN surface admirals were amongst the most reactionary in the world, almost impervious to any sort of change that might challenge their view on how a naval battle ought to be fought. So in a sense what you are claiming (that the USN was unaware of the LL lethality) is true. Not because they didnt know about it, but because they chose not to know....the official record shows that they clearly had access to such information as was needed....., put most simply they didnt act on this information because their concepts were so entrenched and they (the US surface admirals) so unmovable to change that they simply ignored the threat. The result was that their surface fleet , despite the knowledge being there, chose to ride into battle unprepared for the carnage about to be unleashed on them.



Everybody tends to fight the last war, at least the last one they didn't lose. It's a cliché, but it, like all clichés, has some truth behind it (other clichés have Shakespeare behind them ).

I suspect that one of the USN's problems was that its interwar doctrine heavily stressed line-of-battle tactics, even for its cruisers,with the idea of using its 8 in gun cruisers as more as mini-battleships than in the way the RN or IJN intended using their cruisers, which was, at least partly, to support destroyers in torpedo attacks against enemy forces, especially at night and in bad weather. I've speculated, with very little evidence, that part of the reason for this was that the USN considered the Pacific as its key operational area, and the weather around San Diego (the USN's primary Pacific Fleet base at the time) tends to be clear and sunny. Make the USN's primary Pacific base Seattle, and the admirals would have a somewhat different view of normal visibility.
Again, speculating with very little evidence, the fact that successful torpedo attacks are much more difficult in good visibility, the USN deprecated the idea of torpedo attacks, which reduced the amount of effort the USN placed on torpedo development and use (even for aircraft: I've seen posts that the USS _Ranger_ was built without magazines for aircraft torpedoes). So, I speculate that the train of thought was something like this:

Normal visibility conditions are "good."
This means that torpedo attacks are not a viable tactic (even if the destroyer guys think so: their real job is to shoot up other destroyers)
This means that it's preferable for ships to have long range guns
This means that cruisers should have the largest guns practical. Since treaties say that's 8 in, that's what they'll get.
Since they've got long-range guns, they need to operate in strict lines so that they can engage the enemy ships which, because their admirals will have come to the same conclusions we've come to.

The trouble is, of course, that the other admirals came to different conclusions: the IJN decided its cruisers and destroyers existed to attack the USN battle line, which meant that they would have to do so in conditions of restricted visibilty. It's impossible to arm a cruiser (especially a treaty cruiser) with a gun large enough to hard-kill a battleship, but torpedoes will do so quite nicely.

After a few engagements, the USN's leaders changed their tactics to fit conditions. Their strategic concept, which was that navies existed to control the sea, didn't change. The IJN's leaders never really changed their strategic concept, which seems to have been the role of the navy was, pretty much exclusively, to sink battleships. They didn't seem to think about the ships that carried the food and fuel that their people needed to live or the ships carrying the raw materials that their factories needed to produce things like airplanes and ships.

As I've said before: the best thing the IJN could have done was to get rid of the ultra-nationalist loonies who wanted to take over Asia. Failing that, take some time studying what happened to US seaborne trade due to CSN raiders in the American Civil War and how Germany lost 800,000 due to starvation in WW1 as they could no longer import nitrates, and the government chose to produce munitions, not fertilizer, via the Haber process, so its people starved, one of the major factors in Germany's defeat.


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## Garyt (Nov 10, 2014)

One thing I noticed about Japanese cruisers compared to their US counterparts - a big difference in main turret armor. The US cruisers seem to have about 6-8 inches in frontal turret armor, a couple inches on the sides and rear, 2-3 inches on turret tops and 5-6 inches in the Barbettes.

Japanese cruisers on the other hand seem to have about 1 inch of turret armor, and roughly 3-5 inches on the barbettes.

I wonder why? Was the lack of turret armor an attempt to make the vessels not as top heavy so they could carry torpedoes?


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## swampyankee (Nov 10, 2014)

I suspect that it was because the IJN concluded that they would be unable to adequately armor their cruisers against gunfire at reasonable range, so they just put enough armor on their turrets to keep out splinters and machine gun fire. 

The barbettes may have as much armor as they do because it was needed for strength.


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## Garyt (Nov 10, 2014)

I was thinking about it, the barbettes protect the magazines horizontally, the decks protect them vertically. The turrets may have egress to the magazines, but destruction of a turret is not an automatic by any means magazine fire. A penetrating strike to the barbette usually means an issue with the magazine.

My big surprise though is that a Common 5" shell from a US 5"/38 can penetrate an inch of armor up to a about 10 kilometers or so. The Japanese destroyers most common main armament of a 5"/50 penetrates a bit better than the US 5"/38 with a common shell. I'd think that one would want as a heavy cruiser to be able to proof one's main turrets from destroyer fire at least. 

But my question really is where the turrets left "poorly armored" to make allowances for the weight of the torpedoes and tubes?


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## swampyankee (Nov 10, 2014)

Garyt said:


> But my question really is where the turrets left "poorly armored" to make allowances for the weight of the torpedoes and tubes?



I don't know for sure, but that was probably one reason. I remember reading that Japanese ships also tended to be structurally inefficient, so their hulls were heavy for the ships' displacements, so that may have been another factor. Within the confines of a fixed displacement, adding weight to armament means that it's got to be removed someplace else.


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## Garyt (Nov 10, 2014)

Well, if indeed the turrets were lightened due to carrying torpedoes on deck, that is another drawback of the heavy cruiser being torpedo armed.


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## Shortround6 (Nov 10, 2014)

The Japanese _could NOT_ design cruisers that would fight the US cruisers one on one (or eight on eight) as by the 1930 London naval treaty the Japanese were limited. 

"The number of heavy cruisers was limited - Britain was permitted 15 with a total tonnage of 180,000, the US 18 totalling 147,000 and the Japanese 12 totalling 108,000 tons. For the light cruisers no numbers were specified but tonnage limits were 143,500 tons for the US, 192,200 tons for the British and 100,450 tons for the Japanese."

Granted the US might not be able to put all it's cruisers in the Pacific at once but in a big fleet action (or even a series of actions) the Japanese cruisers would be out numbered by the American cruisers. They *had* to have something to equalize the numbers. Assuming 1-2 Cruisers in dock for refit-repair and 1-2 on other duties (and similar proportion for the US and you might see 8-10 Japanese Cruisers trying to fight 12-15 American cruisers. 
DO they go with the torpedoes or _hope_ the Americans leave 40% of their fleet in Atlantic and try for a dead even fight with no hope of replacement ships while the Americans have that 40% reserve?


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## parsifal (Nov 10, 2014)

A typical IJN CA was the Chōkai..... a Takao-class heavy cruiser, armed with ten 20 cm (8 in) guns, four 12 cm (5 in) guns, eight tubes for the Type 93 torpedo, and assorted anti-aircraft guns. Range 8000 miles at 14 knots and a normal complement of 873

Northampton was a contemporary in the USN . She was armed with 9 × 8 in (200 mm)/55 cal , 8 × 5 in (130 mm)/25 cal Mk 10 guns (4x1) , 9 × 21 in (530 mm) torpedo tubes (3x3 which were removed), 24 × 40 mm Bofors AA cannons (6x4), 28 × 20 mmOerlikon AA cannons (28x1). Displacement was 9800 tons. Complement was 1100 men. Endurance unknown but a lot less than the Chokai. 

In terms of armour distribution, the Japanese cruiser was lighter in the superstructure area , but much heavier in terms of deck armour and hull protection. US cruisers were built on the "all or nothing" principal, which meant there were many areas on US cruisers that had no protection, whilst Japanese protection schemes tended to have armour more evenly distributed . Overall, the Chokai had about 40% more armour worked into the ship compared to the Northampton.

Picking one area can yield inaccurate results. US might have better protection in some areas, whilst the IJN might be better protected elsewhere. At 15000 tons to 9000 the Japanese ship is bound to have better overall protection.

Edit

northamptons armouring scheme was a max of 3in over the machinery, 1in deck, 3.75in side armour and 2in deck armour over the magazines. The main gunhouses had 2.5in face armour, 2in roof and 0.75in side and rear. 

Chokai had a main belt of 3.9 in, 4.9 in side and deck armour around the magazines, 1 to 4 in armour worked into the deck. The turrets were weakly protected, with only 1 inch face protection and splinter protection only on the sides or rear. The reason should however be fairly obvious. The northampton had three turrets, with the guns grouped in threes. For Chokai there were five turrets, with each turret holding two guns. A knocked out turret for Chokai represented a 20% loss of gun firepower for the ship, whereas the Northamptons turrets each represented 34% of the ships firepower.


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## Shortround6 (Nov 11, 2014)

AS _built_ the Northampton's had only 4 × 5 in (130 mm)/25 cal Mk 10 guns (4x1) , 6× 21 in (530 mm) torpedo tubes (2x3 which were removed) (Wiki being in error and the Light AA added to the survivors as the war went on. 

The next class, Portland, as built lost the tubes and went to 8 × 5 in (130 mm)/25 cal Mk 10 guns (8x1 ) and 8 X 0.5in MG. 

These classes were being built so fast, in the sense of being ordered and laid down, not in the sense that they were actually being constructed fast, it taking 2-3 years from laying down to commissioning, that lessons learned _while_ building the early ones were not able to be fully applied to the next class. 

AS _built_ the Chōkai/ Takao-class heavy cruisers had 4 four 12 cm (4.7 in) guns, eight tubes for the Type 93 torpedo (4 X 2), and a _few_ assorted light anti-aircraft guns (two 2pdrs?).

The Japanese rebuilt the Takao-class to a greater or lessor extent depending on which ship before the war (in the Pacific, work was being done on some ships in 1940) and AA armament changed to 8 12.7cm (5in) guns in all with variations in light AA and torpedo tubes between ships. 

Mid to late 30s would have been an awkward time to try to rebuild ships to a new tactical philosophy. While you can futz around changing AA guns (even 12-12.7cm guns) doing substantial changes to turrets, barbettes, deck armor and the like is a LOT more work. Yes the Japanese did it to the Mogami's but without the treaties they might have been more inclined just to build new cruisers. 

The Nachi class started laying down in 1924, the Takao's in 1927 and the Mogami's in 1931. 

The US laid down the Pensacola in 1926, the Northamptons in 1928, the Portlands in 1930 and the New Orleans class started in 1930. 

Obviously nobody had any fighting experience with such ships ( director control for battleships being only about 13-15 years old when they were laid down) and carrier aircraft were fabric covered bi-planes with fixed pitch props and 600hp engines _IF_ they were very lucky. And for the US the Lexington and Saratoga didn't even commission until the end of 1927. Too late for any war game lessons ( except table top or meeting hall floor games) to be applied to the first 2 classes of cruisers even if the results of such war games had been allowed to show anything.


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## Garyt (Nov 11, 2014)

> Mid to late 30s would have been an awkward time to try to rebuild ships to a new tactical philosophy. While you can futz around changing AA guns (even 12-12.7cm guns) doing substantial changes to turrets, barbettes, deck armor and the like is a LOT more work.



Really, the only changes I would think needed on the Cruisers would be better AA. The 3.9"/60 would have been first choice, but I'm not sure of the availability of these guns, both when and how many were available. A better weapon then the 25mm probably would not be a bad idea, but I think there were other factors that made the 25mm less effective, most notably being the fire control on the weapon.


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## Garyt (Nov 11, 2014)

How about Japanese destroyers? Personally, I think they may have been the best destroyers of the war. Certainly better in a surface action than almost anyone else. Combination of usually 6 5" guns and the Long Lance made them deadly.

The only real issue i have is the dual mount for the 5"/50 did not traverse quick enough, and without a power rammer it was slow to load when elevated. Some mounts did not even elevate over 40 degrees, makes them almost useless in an AA role. Fix these issues with the 5" armament and I think they are in great shape.

Note- The us 5"/38 reported a great ROF, though there are a few issues here. The 5"/38's ROF depended upon the mount, some destroyers had the faster loading mounts, others were limited to a more pedestrian 12-15 rounds per minute. 

Secondly, a high ROF in surface action is rather misleading. Here are the ranges and the time the round takes to get to target:

5,000 yards (4,570 m): 8.0 seconds 
10,000 yards (9,140 m): 22.0 seconds 
15,000 yards (13,720 m): 43.0 seconds 
17,270 yards (15,790 m): 68.8 seconds

Even at 5,000 yards, you need 8 seconds to see where your round hits, then you need time to correct. So any rate of fire in excess of about 6 per minute is somewhat useless at 5,000 yards. You either have to me at point blank range or you are just firing without bothering to correct aim (most likely at point blank range)for a high rate of fire to really help.

And at 10 rounds per minute, the 5"/50 certainly had the required ROF for most surface actions.

Of course, this also speaks of the single mindedness of much of the Japanese Navy - destroy the opponents surface fleet with your surface fleet.

One destroyer class the Japanese built later in the war was the Matsu class. Smaller than most Japanese destroyers, only 3 main guns (and not the 5"/50), not a lot of torpedo tubes, slow (27 knot max). But these were very inexpensive vessels, and could hunt subs as well as a full blown Japanese destroyer. Japan would have fared better if more of these vessels were built early in the war.


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## parsifal (Nov 11, 2014)

The better gun for the Japanese was the 3.9. Had a sustained rof of 15-21 rpm a horizontal range of 19000m, and n effective ceiling of 13000m. The twin mounting weighed 34 tons
The 5/50 1914 pattern in the standard mount weighed 30 tons for a single gun mount. the sustained rof was 8rpm. Horizontal range was 18400 m and verical range on the 70 deg mount was about 10000m, The newer 5/50 type 1 (1941) had a maximum 22500m and a ceiling of 16200m. A new turret was designed for this gun, with a traverse speed of 18deg per sec, and a sustained rof of 13-18 rpm. There was never a turretted version design, but the land based mount that was built was 19000kg 

If it had been possible to re-equip with the 3.9, which entered production in 1938, the IJN DDs would have gone into battle with roughly twice the numbers of guns in their DDs able to fire further, faster, more accurately and deliver a heavier broadside. It would have been about the same as the 5/38 mount (per gun) in AA, and somewhat more efficient in surface capability. 

Japan never had the slightest chance of re-equipping with the 3.9 however.


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## Garyt (Nov 11, 2014)

The sustained OF for the 5"/50 was 10 rpm, and the *twin* mount weighed 32 tons.

I do believe the 3.9"/60 was a good weapon, the best for AA the Japanese had. I have concerns about it's use as a surface to surface weapon though. A few problems:

1) The Japanese never developed a common round for this weapon, only HE, and my concern here is if they did not develop a round for surface to surface action, did they perhaps not have faith in the weapon for that type of use?
2) The rate of fire as I have mentioned above is very misleading when it comes to surface to surface combat. It's similar to Battleship rates of fire, when one gun has a rate of fire of say 1.5 and another of 2.5. At 30,000 yards, you are looking at a good 50 seconds between when a round is fired and when you see the splashes. Then a bit to adjust the gun usually, so at this range one per minute is just fine. For a 5" type gun, a rate of fire of 10 is more than sufficient unless you are at close to point blank range, maybe 3000 yards or less, where you are looking at maybe 3.5 seconds from firing to splash or hit. So a 3.9"/60 may have a theoretical better broadside when it comes to projectile weight x rate of fire, but in practice the 5"/50 may come out ahead due to heavier shell weight and the 3.9"/60's ROF being supressed due to practicality.
3) The 5"/50 has far better penetration characteristics, as well as a more damaging charge. At about 5,000 yards, the 3.9" penetrates a bit better than an inch, whereas the 5" is looking around 3.5". Even with a HE round, the 5"/50 penetrates a bit better than 2".

Not that the 3.9" is useless for surface to surface by any means - I just think you are better off with the 5"/50 in this situation.

The 3.9" however is a far better AA weapon, so pick your poison I guess.

I just think the 5"/50 was a fine weapon in some regards, with a few modifications like faster turret, a power rammer and the ability to elevate to 75 degrees or better gives you a better dual purpose weapon. Plus as you mention the 3.9" was difficult to come up with in the numbers Japan would need to retool.

What might have worked the best was to have 3 types of destroyers, a "fleet" destroyer like the Akitsuki class, a surface action destroyer like the Asashio class, and a anti sub version like the Matsu class. Prett much what the Japanese did other than there were never enough Akitsuki's to go around, and they should have started earlier and produced more of the Matsu's.

Only difference is I'd like to see the 5"/50 re-designed a bit per my above comments.


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## parsifal (Nov 11, 2014)

ive seen data that says the 3.9 was issued with SAP and AP rounds, but ill check further tonite


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## parsifal (Nov 12, 2014)

well, accordig to campbell, 10cm/65 came in brass casing fixed ammunition, firing nose fuzed HE ammunition and a special ASw round (i confess i dont know what that is).

I checked the 5/50 type 1914....the standard DD gun for IJN destroyers. According to Campbell "Nose fuzed HE of two different types was carried and there were also two types incendiary shrapnel and two types illuminating shrapnel and the ASW round again.

So greater choice ion the 5in calibre, but neither was intended as an AP or SAP round.


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## Garyt (Nov 12, 2014)

> I checked the 5/50 type 1914....the standard DD gun for IJN destroyers. According to Campbell "Nose fuzed HE of two different types was carried and there were also two types incendiary shrapnel and two types illuminating shrapnel and the ASW round again.
> 
> So greater choice ion the 5in calibre, but neither was intended as an AP or SAP round.



Naval shells use different specifications and designations instead of AP/SAP/HE.

They indeed have AP and HE designations, but not SAP. And probably the closest thing to SAP is what they call a "common" round, which is in essence a HE round but with thicker walls designed to penetrate lighter armor.

As a real rough rule of thumb, "Common" rounds are designed to penetrate 1/3 their diameter, so in the case of a 5" shell it should penetrate 1.67". There are so many variables here, so it indeed is a real rough estimate. Muzzle velocity of the gun, range, butt or base fuse, angle, hitting near a joint are just a few of the many variables. But this penetration should penetrate most destroyer armor. It is said that destroyers have no armor, but this is incorrect, it's usually around 1" or 25mm or so of thickness, so a 5"Common round will generally have enough to penetrate a destroyers armor.

These different designation's are compounded by the US use of a "Special Common" round, which is a little but thicker walls and a smaller bursting charge. This round gives the US 5"/38 gun similar performance to the Japanese 5"/50 when it comes to penetrating armor - at the expense of a smaller bursting charge.

It gets a bit confusing when it comes down to caps and wind screens, I know the US common rounds did not have either, not 100% sure of other navies. And I thought, but I could be wrong that common rounds were butt fused. Perhaps it is the Special common round that is butt fused.

But the point of all this is that AA rounds were high explosive, and the preferred round for surface to surface combat was the Common round or Special Common. AA or HE rounds had a larger bursting charge than common rounds, though thinner shell walls and correspondingly less penetration. 

And my point behind all this is that the 3.9" had a HE/AA round, but not a common round designed for it, while the 5"/50 did have common rounds.

Some publications do not differentiate between Common and standard HE. So you don't think I made these up , here is a good guide for shell designations:

Definitions and Information about Naval Guns - Part 2



> and a special ASw round (i confess i dont know what that is).



A blunt "diving shell" type of round, used obviously against subs, but I'm not sure of it's sucess. The Japanese had researched "diving shells", as far as I know other no other navy did anywhere this degree of research. They had some designed for surface to surface as well, and this is one reason why later Japanese battleships had a much more substantial lower belt than other countries battleships.

Shells generally have a tendency to "skip" if they have a relatively flat trajectory, the diving shells were modified not to skip but to dive. My guess is the ASW shells are similar.


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## Shortround6 (Nov 12, 2014)

Destroyers rarely had armor. Local Splinter protection yes but even engine spaces were rarely protected by more than hull plating.
Japanese might have been better served using their 5"/40 guns on their destroyers rather than the 5"/50s. Loss of longer ranges is pretty much an illusion as destroyers were usually pitching and rolling too much to do good work at max ranges. That is assuming they could even spot their shots at much over 12-14000 meters. The 5"/40 at least had all elevation loading.


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## Garyt (Nov 12, 2014)

> Destroyers rarely had armor.



It depends what you define as armor. Splinter protection is usually a good inch thick. If a hull is 3/4 to an inch thick is that armor? Well, it still must be penetrated if one want the explosive effects of a round to not merely explode on the outside of the steel. And steel does not have to be face hardened to serve as armor. The Fletcher class has 1/2 to 3/4 of an inch of steel over almost all of the vessel. Some areas were reinforced a bit thicker.

While 1/2 to an inch of non face-hardened steel is not much when you are looking at cruiser guns or bigger, it can pose an obstacle to 5" rounds or smaller that are not armor piercing. And the Naval versions of 5"or smaller rounds were almost never armor piercing.

One the other hand, when a 8" or bigger AP round hits 1" or less of steel, it well generally penetrate through the vessel before the fuse is set off.

You might be right though on the idea of the 5"/40. It's got a bit less range than the US 5"/38, and significantly less range than the 5"/50. The range does effect more than extreme range though, it effects all ranges other than point blank. As the descent angle of a shell increases, it's accuracy decreases. Of course the more extreme the range the more this effects a round, but it has an effect even at shorter ranges.

Though is this and greater penetration enough to make up for the shortcomings of the 5"/50 as an AA weapon? Perhaps not. The 5"/40 twin mount is about 4 tons lighter than the 5"50, so that is another thing to factor in.

One thing is for certain though, the Japanese were very much in love with the 5"/50. I would think because of it's excellent performance in the surface to surface role. And with the usual complement of 6 of these, they certainly outgunned about all US destroyers who were looking at usually 4-5 5"/38's.

They carried a few more guns, and had guns that performed better in the surface to surface role. Sounds like this was part of that Japanese strategy of outgunning their US opponents on a 1-1 basis, which indeed they did. And again, this showed Japan's lack of focus on vessels that were more multi-purpose.


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## Garyt (Nov 12, 2014)

A quick reason why I think the 3.9" was made only in an HE version, and the 5"/50 with the common round - I'd think the Japanese would want to do what they could to maximize the bursting charge of the smaller 3.9" shell to make it more effective in an AA role. The 5"/50 common round was probably deemed to have a sufficient charge for AA, OR the Japanese did not look at this weapon as a truly dual purpose weapon. Either could be correct.

And another reason why the Japanese likely really loved the 5"/50 - It could be a threat to a cruiser, where a lower velocity and/or hi explosive round would not be. Not to say the 5"/50 could with certainty penetrate a cruisers armor, as there are too many factors such as range, angle, and most importantly armor carried by the cruiser and exactly where the shell hits. I won't go into detail with various cruisers, armor carried and penetration ability of various weapons at range, but suffice to say it (the 5"/50) at least constitutes a threat to many cruisers.


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## Garyt (Nov 12, 2014)

Dupe entry


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## Shortround6 (Nov 12, 2014)

Hull plating is NOT armor. Armor does NOT have to be face-hardened. Destroyer hull plating was often not the same As cruiser, battleship, or merchant hull plating. 
Some countries used high-tensile steel for destroyer hulls as it has a higher strength to weight ratio. But it is not armor. It resists stretching better but still has a bit of give. Even homogeneous armor can be too stiff for structural work and tend to crack. Hulls can do a fair amount of bending in a sea way. But even high tensile steel is much less resistant to penetration than real armor.

The U.S. had been reluctant to give up the 5"/51 used on some WW I destroyers and as battleship secondaries and go to the 5"/38. But even the French found they had trouble spotting the shell splashes of 5.5" guns with much heavier shells much past 13,000 meters from their super destroyers.
The extra range was pretty much an illusion unless you can find combat reports of destroyers actually hitting at 12,000 meters and above.


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## Garyt (Nov 12, 2014)

> But even high tensile steel is much less resistant to penetration than real armor.



It's not as much of a difference compared to steel armor. I would think you are familiar with Nathan Okun's work, probably the best work out there on naval armor penetration? Here is the number he gives for high tensile steel, commonly used in naval ship's hulls:



> AVERAGE HIGH-TENSILE CONSTRUCTION AND LIGHT ARMOR STEEL (HT/HTS)
> USAGE: Ship construction, light armor, "Protective decks," and anti-torpedo bulkheads.
> AVERAGE QUALITY: Estimates: 1895 = 0.8, Post-World War I = 0.85 (when hit by projectiles up to 8", dropping off slowly and steadily when hit by projectiles above this size at a rate equal to German Ww)



That's 85% of class A armor, which comes in at 1.0 the best US armor available. Japanese armors don't even receive a full 1.0.


So while not as tough as armor grade face hardened steel, it works pretty well. And ironically perhaps, it works it's best on shells of 8" or under. It's really not designed nor does it function well against battleship sized shells.



> The extra range was pretty much an illusion unless you can find combat reports of destroyers actually hitting at 12,000 meters and above.



Again, it's not as much about extreme range as it is the inherent accuracy at shorter ranges. Even at 5,000 meters, a 5"/50 is going to have a flatter trajectory than a 5'/40 round, making it more accurate.

For example, I'm sure the MK108 cannon has a range far outside it's effective range, but even at half of it's effective range it is inherently less accurate than a Mk103 30mm cannon for instance.


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## parsifal (Nov 12, 2014)

Accuracy is an issue, but by far the most important factor was rof. And rof had not much to do with the hardware. US DDs in theory had a clear advantage in their rofs, but often were just milling about not knowing whether to open fire or not. Hesitation is what causes fire rates to vary, not much to do with the gun (or the mounting) itself. If the hardware was an issue, the dominant effect was the ready use supply of ammunition rather than the rate they could be put into the breech. In that regard, it would be interesting to know how fast the 5/38 actually was on a sustained basis, say over 300 rounds, compared to the 5/50. I would hazard a guess and say...not much faster. 

5000 yds is actually a fairly long range for a night engagement. They might get down to 2 or 3000 sometimes even less. Day engagements you could count on one hand just about. at that range it was how fast you could fire, and how well your team could work together without having to constantly re-assure each other


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## Garyt (Nov 12, 2014)

> Accuracy is an issue, but by far the most important factor was rof.



Again, really does not have much of an effect on surface to surface combat. 

ROF again is misleading. The question is simple, is the rate of fire quick enough to reload by the time the round gets to the target. The answer is yes in the case of the 5"/50. 

It's really rather simple. You fire rounds for a straddle. Until you straddle the target, you are waiting for a round to splash before firing another. Once you straddle the target some aspects of a superior rate of fire can come into play, but if you again miss you are trying to correct your fire, again requiring time for the shell to hit and then see the splash. If and at what range manual corrections actually work as opposed to looking for the splash I do not know. Another issue is that rate of fire with naval cannon is not proportional to the amount of hits. Mount dispersion is the culprit here. 

EDIT:

At 2-3000 meters or yards, we are looking about 3-4 seconds to impact, which would require a 15-20 rounds per minute to maximize IF there were no adjustments after each hit or miss. I'd think you would have to allow at least a few seconds to make adjustments, which may put is in that 10 round rate. If no adjustments need to be made, we might be at that 15 or so rate per minute.



> In that regard, it would be interesting to know how fast the 5/38 actually was on a sustained basis, say over 300 rounds, compared to the 5/50. I would hazard a guess and say...not much faster.



I think crew fatigue would be the biggest issue here. And without a power rammer, I would think the Japanese would fatigue faster. 

Of course, 300 rounds is a lot, I think the standard destroyer carried in the 200-400 range per gun, so you might be looking at exhausting the boats entire main armament ammo supply.


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## parsifal (Nov 12, 2014)

what you are describing regardimg fall of shot is very true for day engagements, but far less so at night. It did happen, and often enough to matter, but also, there were occasions when observation of the shot fall was not possible. As often as not the fight was a blindfire exercise. Sometimes its just a matter of assessing the range speed bearing and course of the target, firing off 10 rounds or so, observing if there were any results, adjusting the bearing and ranges for your guns and doing it all again. The Japanese would often use searchlights to locate and range a target, but searchlights would rapidly lose effect in a smoke filled battlefield and of course made that ship a target. 



> Of course, 300 rounds is a lot, I think the standard destroyer carried in the 200-400 range per gun, so you might be looking at exhausting the boats entire main armament ammo supply.



Happened a lot actually


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## Garyt (Nov 12, 2014)

> but also, there were occasions when observation of the shot fall was not possible. As often as not the fight was a blindfire exercise. Sometimes its just a matter of assessing the range speed bearing and course of the target, firing off 10 rounds or so, observing if there were any results, adjusting the bearing and ranges for your guns and doing it all again.



I'd think also that at close enough ranges during the day this would be the case too. Though I'd think for this to make any sense during the day you would have to be at a kilometer or less (preferably less), and/or ave very obscured vision. Heck, to maker it intact to that close of range there would probably need to be somewhat obscured vision in the first place.

One amazing thing though to me is Yamato's hit or damaging near miss if you prefer at 34,000 yards on the Gambier Bay. And this was done with both parties on the move strictly with optics, no radar. I think the Japanese fire control is not often given the credit that it should get. Their optics were the best in the world, and optics during the daytime were a match for radar. BTW, many of the companies that worked on optics for Japans Navy such as Nikon would go on to gain a large market share of the camera industry after the war.


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## Shortround6 (Nov 14, 2014)

Actually rate of fire was fairly important. 
Depending on weather and ships rolling a high rate of fire gave you more firing opportunities. Ships tried to fire at the same point in the roll for consistency. Period of roll rarely matched the rate of fire. 
More importantly, _once_ the range was found at the low rate of fire, waiting for the salvo to land before firing the next one, the rate of fire would be increased. Aside from trying to smother the enemy before he hit you, this gave a faster "data" stream on the range or range change. If the enemy dodged a salvo after the last full time of flight time period he had that much longer to keep dodging until the next one arrived. With faster salvos the range data gets updated quicker and the 'miss' distance is less. 

Large danger spaces worked pretty well at short distances and were a big help to guns in local control. Once range data was coming from a range finder on a gun director the 'flatness' of trajectory became somewhat less important. At longer ranges where the angle of decent was around 45 degrees (or above) the deck of the ship was a bigger target than the side.


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## Garyt (Nov 15, 2014)

> Actually rate of fire was fairly important.



I was speaking to someone who's had some experience (3rd hand actually) on a destroyer in WW2, and said if they were at a range of 5000 yards, they would be in rapid fire mode not waiting for splashes. 

I had also read (forget where, might be Larry Bond) that rate of fire is not proportionate to hits, they greater the rate of fire the lower the accuracy.

A light bulb then kind of went off.

Let's say we have a US and Japanese destroyer exchanging fire at 5000 yards, and the US destroyer base ring mount with internal hoist giving the higher rate of fire (interestingly enough, sometimes a destroyer would have both types of mounts.

The US Vessel can fire a round every 3-4 seconds, the Japanese every 6 seconds. The rounds are airborne for about 8 seconds. The US destroyer fires at it's maximum rate, allowing little time to adjust fire. The Japanese destroyer fires either every 6, or waits for the splash and is firing maybe every 10 seconds.

While the US destroyer may pump out 19 rounds to the Japanese guns 10, the hits obtained will be much closer.


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## Garyt (Nov 15, 2014)

Dupe post


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## Glider (Nov 15, 2014)

More important than ROF was who hit first. Once you have a straddle then go to high ROF, if you don't do that then all you are doing is spraying shells around at least as importantly tiring out the gun crews.

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## Garyt (Nov 17, 2014)

> More important than ROF was who hit first. Once you have a straddle then go to high ROF, if you don't do that then all you are doing is spraying shells around at least as importantly tiring out the gun crews.



Very true, the initial staddle is indeed important. But we also have to realize these are not stagnant objects - you have a firing ship moving at 20 knots+ and a target ship moving at 20 knots +, one or both of who may be moving evasively.

With two objects moving at 25 knots each somewhat towards each other, the targets relative position moves roughly 85 feet per second. Even on a rapid firing 5 inch (20 rounds per minute) that is 250 feet between each round.


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## Shortround6 (Nov 17, 2014)

Which is a good reason why once they found the range, or got close, they fired at a pretty quick pace and didn't tie the rate of fire to the time of flight. They wanted fast feedback/updates on the firing solution.


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## Garyt (Nov 17, 2014)

> Which is a good reason why once they found the range, or got close, they fired at a pretty quick pace and didn't tie the rate of fire to the time of flight. They wanted fast feedback/updates on the firing solution.



Problem is here that by the time they can look at where round 1 hit and how it needs to be adjusted, rounds two and 3 will have already been fired. SO you are in essence firing 3 rounds, adjust, repeat. I can't see in a combat situation where they will be able to keep which rounds are hitting/missing seperate. Kind of like hosing down a target.

And yes, the rate of fire will be higher (maybe with a US 5"/38 2x that of a Japanese 5"/50), but you are also going to have a lot more misses. How many is hard to say, but you are certainly not getting 2x the hits on average. 

It would be interesting to see any info that references accuracy at a given rate of fire and how it changes according to rate of fire. I remember reading that it's certainly not straight line when comparing rate of fire to hits, but I forgot where I read this.


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## parsifal (Nov 17, 2014)

These are some basic stats on battles. If you look at a few of them, it will be seen that the gun crews had to be firing more or less flat out to achieve the expenditures they did. On the basis of the statistics...rof is far more important than waiting for accuracy

This might take several posts

Italian theatre
On 28th June 1940 RN needed nearly 5000 x 6” shells to sink one Italian Destroyer

At Calabria [July 6th 1940] reportedly 923 x 6” shells from two British CL = 1 hit. In a long-range battleship duel 335 big gun shells produced only one hit and 5 near misses, while the 12th Italian destroyer squadron expended 400 shells without any hits.

Cape Spada [July 19th 1940] 1300 British 6” shells produced 5 hits; while 500 x Italian 6” shells yielded one hit.

At Cape Passero [12th Oct 1940] the British Cruiser HMS Ajax unleashed 490 x 6” shells getting between 8-10 hits on the Italian T-boats DD in the rather one sided short-range night ambush.

Long-range duels at Cape Spartivento [27th Nov 1940] reportedly 666 Italian Cruiser shells resulted in only 2 hits while 4 British Cruisers obtained two 6” shell hits after “expending their typical prodigious quantities of 6-inch shells,”

Pantelleria 10th January 1941; The HMS Jaguar expended 94 shells and “ closed to within three hundred yards and raked the helpless torpedo boat, igniting fires along her entire length”. Meanwhile the HMS Bonaventure expended 600 x 5.25 “ shells without any results.

14th June 1940 RN destroyers required 700 shells to sink an Italian sub that could not submerge due to toxic gases. 

Off Harmil Island Oct 20-21 1940, RN cruiser HMS Leander plus the destroyer HMS Kingston required 129 x 6” shells plus 693 x 4.7” Shells to sink the Italian Destroyer Nullo.

RN attack on Tripoli harbor sunk 3 small merchant ships [1500-2700 tons] with 478 x 15” shells plus 1500 x 6”/4.7” shells.

June 9th 1941 HMS Jackal expended 611 x 4.7” shells and achieved 1 hit and 1 near miss on the French Destroyer Leader Guepard, which was able to land a 5.45” shell hit on HMS Jackal in return [no mention of ammo expended].

Nov 9th 1941.An Italian escort of a dozen cruisers and destroyers fumbled around blind while a well lead RN squadron of four radar equipped destroyers and Cruisers shot up and massacred a convoy of 7 German ships. Contrasting the achievements, two Italian CA got one near miss after expending 207 x 8” shells and 82 x 3.9” shells. British were short on ammo at Malta, but as example one of the two RN cruisers expended 259 x 6” shells. No info on just how many hits these RN warships attained, however they managed to sink all 7 of the merchant ships plus a destroyer and damaged 4 more destroyers. Clearly a good day for the British and a bad day for the Axis. One of the most basic lessons of modern naval warfare is demonstrated in this action. Superior training and leaderships trumps numbers and potential firepower any day of the week. 

Maritza convoy was attacked 24th Nov 1941; two Italian torpedo boats expended 304 x 3.9” shells and just got a near miss.

Second Battle of Sirte, 22 March 1942 fought in rough seas with gale force winds, 1492 Italian shells produced two confirmed 6” shell hits causing major damage on two destroyers plus 4 near misses with 15” Shells caused light damaged on 4 RN warships. The RN responded with 1600 shells from the Cruisers and 1300 from the destroyers and netted only on hit.

During Pantelleria June 15th 1942, two Italian Cruisers fired an estimated 800 x 6” Shells and obtained 14 hits.

During the Battles of Oran 8-9th Nov 1942, the French Destroyer Leader Typhon expended 220 x 5.1” shells and got a single hit, while the British Cruiser HMS Jamaica got only one hit with 501 shells. Another British Cruiser in this same battle got 6-8 hits but no info on the number of shells fired [could be similar?].

In the Messina convoy battle June 2nd 1943, the HMS Jervis got two hits on 142 x 4.7” shells expended.

16 battle actions summarizing 13224 shells of 4”–15” guns obtained 43 hits and 7 near misses and 8708 shells to sink 10 merchants + 2DD + TB+ Sub

Battleship fired 813 shells produced one hit and 5 near miss
Cruiser fired 8941 shells produced 37 hits 
Destroyer fired 3677shells produced 5 hits and 2 near misses.

Italian warships fired 4856 shells and got 19 hits and two near misses.255:1
British warships fired 8364 shells and got 23 hits and five near misses.363:1
French warships fired 220 shells and got one hit. 220:1
Unfortunately the British are not forthcoming with much of their ammo expenditure info so some of their best battles have to be left out. Which is probably for the better since they would just skew the data. Most of these best battles were ambushes set up with Enigma information and exploiting the lack of Italian Radar to ambush at close quarters at night by Radar equipped RN warships. You can see the effects since these actions usually start when the Italians finally detect the British ships at just a few kms range.


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## Shortround6 (Nov 17, 2014)

If you are using director control you are not "hosing down a target" you are firing salvos. All shells fired together and all shells landing together (or with in a fraction of a second). This means that your salvo rate is tied to your slowest gun/crew. Any fire control officer worth his stripe/s should be able to figure out which salvo is which.


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## parsifal (Nov 17, 2014)

Japanese vs Allies. (Part I of II) 
Balikpapan 24th Jan 1942 ; USN got 3 hits with 25 torps.

Badung Strait 19-20th Feb 1942; IJN got 9 hits with 662 x 5” shells 

Battle of Java Sea, 27th Feb 1942 IJN got ; 
1619 x 8” shells = 5 hits
221 x 5.5” shells= no hits
515 x 5” shells = no hits
153 x LL Torps = 3 hits.

Bali Strait 1st March 1942 USN; John D Edwards expended 240 shells with no hits.

Borneo Battle 1st March 1942, USN DD expended 345 x 4” shells without any hits. IJN expended 1171 x 8” shells and 1479 x 5” shells plus 25 torps to sink the crippled cruiser HMS Exeter and two DD escorts.

1st March 1942, a USN DD was sunk in a battle with two IJN Battleships plus a pair of heavy cruisers. To sink this destroyer they had to expended 297 x 14” shells and 844 x 8” shells plus 194 x 5-6” shells.

2nd March 1942, two USN DD were sunk in a battle with two IJN heavy cruisers and three DD, that expended 799 x 8” shells plus 635 x 5” shells 

Battle of Savo Island 9th Aug 1942; Japanese cruisers ambushed 5 American cruisers at night and massacred them. The 6 x IJN Cruisers surprised the Americans at long range with 57 Long Lance torps that resulted in 6 hits, and in the follow on close battle launched 1872 shells getting 215 hits. The 5 USN Cruisers and two DD replied with 471 shells getting just 8 hits.

In Sealark Channel 25th Oct 1942, a pair of old American DD battled with three modern IJN DD, with each side suffering one Damaged DD. In this exchange 450 IJN shells produced 2 hits, while 120 USN shells resulted in splinter damage from near misses.

First Battle Guadalcanal 13th Nov 1942, many warships were hit with numerous shells, but no record of ammo expenditure on each side. The most decisive weapons seem to be the 72 Long Lance torps that resulted in 6 hits finishing off 5 American warships.

Second Battle Guadalcanal 14-15th Nov 1942. Again many warships were hit on each side but not much record of ammo expenditure on each side. What we have is two USN BB firing in total 232 x 16” shells and getting 9 hits, while 510 x 5” shells resulted in 40 hits. Since the battle was at night in amongst islands most fighting was done at short range and finding the enemy in such a confused battle was the biggest issue by far.

Battle of Tassafaronga, 30th Nov 1942. Five American heavy cruisers plus 6 DD fought an veteran force of 8 Japanese DD.. What ammo details we have, report that the USN fired 425 x 5-8” shells plus at least 9 salvos from a CA and resulted in a number of hits that sunk a IJN DD her and splinter damaged another DD. In return the Japanese appear to have fired 44 Long lance undetected and got at least 5 hits, sinking one Cruiser and another three crippled by the Long Lance. Again the battle was at night in amongst islands and at short range.

Battle of Komandorski Islands, 27th March 1943. 4 Japanese cruisers and 3 DD chased 2 USN Cruisers and 4 DD in a long-range gunnery clash at morning light in moderate seas. Americans expended 1103 x 6” 8” shells without registering any hits at 16-20,000 yards, while 1611 Japanese 8” shells registered 8 hits and a near miss, that badly damaged an American CA DD. Fearing the Cruiser lost the US commander ordered his remaining DD to counterattack and drive off the pursuing IJN force. This they achieve when they got a couple of hits with 985 x 5” shells, while the Japanese in return registered one 5.5” hit plus a near miss after expending 231 x 5.5” shells from there screening DD.

Battle of Vila-Stanmore, March 6th 1943. A force of 3 x USN CL plus 3 x DD ambushed a pair of Japanese DD on a moonless night using SG radars. Both IJN DD were quickly sunk at close range [few km] with the expenditure of 1101 x 6” shells and 538 x 5” shells. Resembled RN ambushes of Italian fleet in the Med.

In surface battles From after Pearl Harbor to march 1943, the allies had only sunk 9 major Japanese warships [DD on up] plus the BB Hiei, while they had lost 37 in exchange. Even including other actions [air/sub], the Japanese had sunk 77 Allied warships [546,000 tons], while they had lost 46 major warships in return [305,000 tons]. Looks like 7181 IJN shells registered 234 hits or 31:1. In response the Americans fired 4006 shells getting 59 hits 68:1 hit rate. IJN Long Lance seemed to have been most effective registering 20 hits on 326 torps launched or 16:1 hit rate. USN appeared to have launched about 25 Torps with 3 hits or 8:1 hit rate. Low numbers mean that the limited range probably inhibited their use however. 

Encounter off Rice Anchorage 5th July 1943, 4 IJN x DD rushed troops to New Georgia but abandoned the mission when the detected USN force of 3 cruisers and 4 DD. In the first use of new Japanese radar equipped ship, they launched a volley of 10 Long Lance at 11,000 yards and got one hit on a USN DD that sunk.

Battle of Kula Gulf, 6th July 1943. 11 Japanese DD landed 1600 troops plus supplies to New Georgia, while a force of 3 USN Cruisers and 4 DD escorted USMC troops in a moonless night. Again the Japanese using Radar surprise the USN and launched about two-dozen Long Lance torpedoes, before the Americans were aware of their presence. The Americans firing by radar were then able to hit at least a dozen times with 5-6” shells sinking two IJN DD and damaging four more. However during the action a USN Cruiser was clobbered by 4 Long Lance torpedos and sank so quickly that they were unaware of her loss until after the battle.

Battle of Kolombangara, 13th July 1943. A force of 5 Japanese DD plus a Cruiser transported troops yet again up the New Georgia Sound. USN Scout seaplanes detected these and a force of 3 Cruisers and 10 DD intercepted them in failing moon light night. The USN launched 19 + 17 torpedoes at long range in an effort to duplicate Japanese tactics but it was too late since 29 Long Lances were already in the water. Then the radar controlled 6” guns of the USN cruisers launched a deluge of 2630 x 6” shells sinking the Japanese cruiser. The Americans already believing they had sunk the bulk of the force, went after the escapes only to be ambushed themselves. The Japanese had withdrawn to reload there torpedo tubes and launched another batch of about two-dozen Long Lance Torps, which obtained 5 hits sinking a DD and crippling all 4 allied cruisers. The Japanese were still able to land their troops.

Vella Gulf 6-7th August 1943 Americans pulled off a perfect ambush with 6 DD attacking 4 IJN DD overnight, in Squalls. They launched 22 of 34 Torps unknown to the Japanese, who then lost 3 of the DD to 6 torpedo hits. In total USN got 8 torpedo hits on 34 fish launched. They also expended 655 x 5” shells getting ‘numerous hits’, after the torps had halted the targets. The Americans were finally learning how to fight the Japanese way.

Horaniau battle, 18th August 1943 .USN force of 4 DD attacked a small Japanese troop convoy [16 barges and boats plus 6 armed trawlers] escorted by 4 IJN DD. The USN engaged the Japanese DD with 3028 x 5” shells and got a couple of hits, after which they ran down the convoy but were only able to sink two of the armed trawlers and one barge. Japanese were able to land their troops.

Vella Lavella, 6th Oct 1943. A dozen small Japanese craft sought to evacuate 590 troops on Vella Lavella, covered by 6 IJN DD. A force of 3 USN DD were ordered to intercept. In another confusing night battle 48 Japanese Long Lance torpedos sunk one DD and crippled another, while gunfire battered the other USN DD. The Americans sank one of the IJN DD with 680 x 5” shells getting 5 hits at long range, while 2 out of 16 torps fired finished this target. The evacuation was a success.

Empress Augusta Bay, 2nd Nov 1943. The Japanese force of 4 cruisers and 6 DD was sent to land troops on Bougainville to counter American landings already there. An American force of 4 Cruisers and 8 DD sought to intercept this force and drive it off. The USN, finally understanding the threat of the Long Lance and their own advantage in radar, planned a long-range night battle with a surprise massed torpedo attack followed by radar directed cruiser firepower to destroy the IJN force. In a dark night with showers and minimum visibility, the Japanese at the last moment avoided the initial massed torpedo barrage and the battle quickly broke down into confusing action where both sides suffered ship on ship collisions to add to the carnage. Reportedly 5296 American 6” 5” shells netted about a dozen hits sinking a cruiser and a DD plus damaging 3 more DD. The Japanese netted about 6 major hits damaging 3 DD [ammo expended unknown], while one long Lance crippled a DD out of about 34 fired.

Cape St George, Nov 25th 1943: 5 x Japanese DD escorted a reinforcement convoy to Buka base, while 5 x USN DD rush to intercept them. Again the Americans pulled off a successful torpedo ambush resulting in 3-4 hits from 15 torpedos mass launched at moonless night. One IJN DD sank right away while another was slowed so it could be finished off with gunfire and more torps. They finally ran down another IJN DD with gunfire and finished it with torps at short range. However the Japanese troop convoy got through.

Truk 17th Feb 1944; After the Japanese abandoned the forward base of Truk, a fleet of 11 American fast carriers and 6 BB with 32 escort Cruisers and Destroyers surged across the Western Pacific to seize this critical island base. Air attacks damaged several last minute stragglers sinking an AMC, before the screening USN Destroyers caught up with them. USN was able to run down these DD and sunk two of them expending 58 x 16” shells + 400 x 8” shells and 124 x 5” shells. This featured the longest-range salvo at 39,000 yards, which claimed to get straddles.


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## parsifal (Nov 17, 2014)

Japan vs Allies (Part II of II)

Battle for Biak 8-9 June 1944. Japanese planned landings near New Guinea with a force of 5 x DD towing troop barges in moderate seas on a moonlight night. A large USN force of 3 cruisers and 13 DD moved to intercept them after being tipped off by a nearby US sub. The Japanese detected them in time to launch a torpedo barrage, which the Americans detected and avoided. Then the Japanese DD cut loose their barges and fled. In a long range gun duel the USN expended 2005 x 5” shells and obtained 2 hits , damaging one of the retreating Japanese DD. After the DD were driven off the USN was disappointed to find and sink only one troop barge.

Muka Jima, Aug 4th 1944. Typical of late war actions the USN fast carrier task group hunted down a convoy with 8 transports and three escorts [DE and 2 x DC]. Carrier planes found and sank 4 of these transports before a taskforce of 4 Cruisers and 3 DD ran down the convoy and sunk the other four transports plus the DE.

Battle of Surigao Strait, Oct 25th 1944; The Japanese command developed a number of plans to counter American advances on Japan, when it became clear that Macarthur planned to move on the Philippines, Toyoda executed the naval component of “Sho-Ichi-Go’. Four separate fleets converged on the Philippines to defeat Nimitz’s Third and Seventh Fleets. In the south, Admiral Shima’s Third Strike Force with 2 CA + CL+ 6DD plus Admiral Nishmura’s 2 BB a CA and 4 DD and clashed with USN Admiral Kinkaid’s Task Group 38.4 with 6 BB + 4 CA + 4 CL 26 DD. This moonless night battle lasted 5 hours and the out number Japanese were outfought and defeated loosing both BB and 3 DD, while 2 cruisers were crippled and another damaged along with a DD. The Americans only suffered one DD crippled in the exchange from friendly fire. Americans were again successful in torpedo attacks launching about 90-100 torpedos resulted in about 10 hits helping to sink both BB and two DD. USN BB expended 273 x 14-16” shells and got 6 hits finishing off one Japanese BB. American Cruisers expended 553 x 6-8” shells getting 11 hits crippling an IJN CA. Overall the Americans fought well, while the Japanese fought poorly apparently suffering from conflicting leadership and poorly trained crews.

From the summer 1943 on the USN fired 11835 shells getting roughly 36 hits for a rate of 328:1 hit rate. There do not appear to be much reliable info on hits rates for IJN. The bulk of the American shells were launched using radar, suggesting its hit rate is an order of magnitude lower than direct sight. Looks like IJN best response was launched 169 Long Lance getting about 14 hits for a 12:1 hit rate. Americans in response launched 191 torps getting 24 hits for about 8:1 hit rate.


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## parsifal (Nov 17, 2014)

German vs RN/allies
Look at River plate. Graf Spee got ; 9 x 11" shell hits on 405 shells expended. no hits on 600 x 6" shells expended 2 hits on 200-230 4" flak shells expended.

RN were not any better, they got 200 x 8" shells yielded only 3 hits plus 2065 x 6" shells expended yielded just 17 hit 

To sink Glowworm the nazi expended 31 x 8"= 2 hits and 104 x 4" shells expended = 4 hits ...which seems alright for shooting.

In 1940 Renown fired 230 x 15" shells and got 1 hit on Gneisenau, while it took 1065 x 4" shells to get one hit on Scharnhorst as well.
Return fire looks the same, the Germans got 2 hits on Renown with 249 x 11" shells expended. The German secondaries got no hits on 91 shells expended.

Most of the serious damage done at Narvik seems to be done with Torpedos even the Warspite mighty guns didn't do much... and Narvik was much more restricted waters than any Pacific battles. The bay was only 2-4 miles wide over most of its 30-mile length!

To sink HMS Glorious the ‘twins’ expended 387 x 11” shells registering only 5 hits plus 1148 x 6” shells, which don’t seem to have hit anything.

Off ‘The channel’ in Oct 1940 the British struck again with 5 DD and two Cruisers firing 1200 shells and got only two hits , one on each of two out of four German DD. 

On Christmas day 1940 the Hipper attacked a British convoy and got four hits on British Cruiser HMS Berwick with 185 shells and a couple of hits on convoy ships with 113 x 4” flak shells fired. The three British cruisers fired some 6-8” shells but got nothing for their efforts.

Sinking of HMS Hood and battering the POW at “the Denmark Straits”, the Bismarck expended 93 x 15” shells getting about 7-9 hits, while PE got 5 hits on 178 shells fired….not bad shooting at all. Sinking the Bismarck , like Narvik and the HMS Hood sinking, has to be acknowledged with qualifiers, She could not maneuver and could barely make 10 knots; making her a easy target since her speed slowed and the ranges got down to couple of kms, towards the end. However the total expended by Rodney and KGV was 375 x 16” shells and 339 x 14” shells. It appears about 40 major hits were registered on Bismarck possibly 1/3 14” and the rest 16”. The secondaries plus the cruisers fired 2157 x 6-8” shells getting something like 300 hits. Had this been any other ship it should have sunk after ½ of these hits.

At St Nazaire in 1942 the 5 German TBoot got two hits on ~ 300 shells fired [estimates 240-360 shells]. 

On May 1942 German destroyers attacking a British convoy expended 584 shells and only got 2 hits plus two near misses, causing light ship damage from splinters.

In the Barents Seas battle 31st Dec 1942, Hipper struck again hitting 3 times with 120 shells, crippling the destroyer HMS Onslow. 

Typical of German convoy escorts, in one battle in January 1943 four UJaggers fired 41 x 88mm shells at a pair of Soviet Destroyers getting a single hit and driving them off. 

In the North Cape battle at the end of 1943, the HMS Duke of York managed 13 hits with expenditure of 446 x 14” shells. Infact it seems the 55 torpedos producing 11 hits, are what finally sunk the Scharnhorst, although the long range 14” gun fire was instrumental in slowing the German battleship down to be torpedoed.

The Battle of Biscay action December 1943 saw 11 German Torpedoboot and Zerstörer’s battle a couple of British Cruisers in rough seas The British cruisers expend the bulk of their ammo, sinking a German Destroyer and two Torpedoboot, while the Germans expended 34 torpedos in 8 separate attacks with nothing to show for it, infact it appears the British didn’t even notice most of these attacks. Franz Kohlauf recommendation on a couple of long-range surprise mass torpedo firings at the start of the battle was ignored with predictable results. When ever he pulled off this tactic it usually paid off with handsome dividends. 

In naval counter attacks around ‘Normandy landings’, the German Torpedoboot flotillas launched a total of 55 torpedos getting only one hit.

So in summery 4768 German shells from 5-15” guns registered about 47 hits or about 101:1. Breaking this down further we see 34 hits from BB/CA primary batteries shooting 1398 shells or 41:1 rate, and the smaller guns got 13 hits on 3370 shells expended or 259:1. So enough info to suggest that the bigger guns generally do much better. 

The British in seven documented cases reportedly fired 8077 shells and got 377 hits for an astonishing rate of 21:1. That is until we look closer as most of those hits were the Bismarck, which would not sink [340 hits out of 2871 shells fired 8:1]. If those are removed the figures group average become 33 hits on 5206 shells fired or about 158:1.


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## Garyt (Nov 17, 2014)

Impressive amount of info there, Parsifal 

Unfortunately what we don't see is the amount of hits based upon what range and ROF were being used at the time, unfortunately I don't think this is something that can be effectively researched without a huge amount of time being spent on the subject.

One interesting thing though:



> So enough info to suggest that the bigger guns generally do much better.



I agree. And it might be mere coincidence (though I doubt it) that large guns have a much higher hit rate, and they also have a much slower rate of fire.



> If you are using director control you are not "hosing down a target" you are firing salvos. All shells fired together and all shells landing together (or with in a fraction of a second). This means that your salvo rate is tied to your slowest gun/crew. Any fire control officer worth his stripe/s should be able to figure out which salvo is which.



That is of course, unless you are firing under local control, correct? And I really have my doubts that you can fire a round every 3 seconds or so in anything but local control, so matching the 5"/38 ROF of 15-22 rounds per minute would be very difficult. Local control though fares much better as the range gets much closer.


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## parsifal (Nov 18, 2014)

Thanks, but its not my work.......the guy that did write this is an absolute genius at naval warfare.


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## Garyt (Nov 18, 2014)

You know Parsifal, this discussion on rate of fire really has me thinking. It just does not seem feasible that one could fire a round(s), get input from the director, assessed by the plotting rooms, instruction then relayed to the guns for the next round to be fired, all in a 3 second interval that would be required to match a 20 rounds per minute pace.

Maybe I've got this wrong, but I would have to think for such a high rate of fire the stations would have to be in local control, unless I am missing something here. Which could indeed be the case 

Finding someone with experience though on firing procedures for manually loaded 5 inch guns would be tough.


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## Garyt (Nov 18, 2014)

To add to what I had just said, I was having a similar discussion on a naval forum. Got a reply from someone somewhat familiar with WW2 era fire control. It looks as though the director was indeed used - but the "spotting" might have been done once every 3-5 salvos in a situation like this, the salvos fired between intervals are all based on the most recent update.



> is generally referred to as the problem of ‘spot pyramiding’ (often leading to over correction during rapid fire). This happens when the interval between shots or salvos is less than the time of flight plus the spotting interval, meaning that when a salvo lands there’s already another one (or more) in the air. In such situations the spotting will undoubtedly become muddled. The only way to prevent confusion is for the spotter to stop reporting each and every fall of shot, and only do so when he's asked to do it. What happens is that the guys in the plot press a button on the rangekeeper (the main fire control computer) and then after a calculated interval that makes allowence for time in flight, a buzzer will sound, alerting the spotter that a salvo is about to land that needs to be reported on.



I don't know exactly what the spotting interval would be, but it would require data fed to the director, this being relayed to the plotting room, the firing solution being calculated, relayed the the individual turrets and corrected.

I't think with a 5" gun at 5000 feet this would be a good 15 seconds, 8 for the flight of the salvo and 7 to accomplish all the fire control steps listed above. Actually, 7 seconds seems little time to accomplish all the above, but I am not sure.

If this is correct, with a firing rate of 20 per minute, we have 5 salvos fired for every one correction.

Perhaps this has a lot to do with the lesser accuracy of smaller guns (smaller compared to a cruiser or battleship weapon).


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## Shortround6 (Nov 19, 2014)

different distances might require different solutions/techniques.

Some Navy's, when firing long distance with battleships/cruisers where the time of flight exceeded the rate of fire, adopted spit salvos. 1/2 the guns firing and then the other 1/2 to keep the time gap between salvos landing down. This did depend on turret layout/design as some turrets didn't allow independent loading or elevation. 

A number of Navies got it wrong in emphasizing long range gun fire from destroyers during the 1930s as the very same guns, mounted on cruiser or battleship hulls had longer _practical_ battle ranges. Especially the worse the weather got. The guns had higher command (and were dryer), the gun directors/fire control was higher up giving better visual range and the steadier hulls provided both a better firing platform and higher rate of fire in rough weather. The guns favored by many navies during the 20s and 30s for destroyers could easily out-range their fire control equipment.


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## tomo pauk (Nov 19, 2014)

Thanks for sharing the stuff, parsifal.


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## Garyt (Nov 19, 2014)

> So in summery 4768 German shells from 5-15” guns registered about 47 hits or about 101:1. Breaking this down further we see 34 hits from BB/CA primary batteries shooting 1398 shells or 41:1 rate, and the smaller guns got 13 hits on 3370 shells expended or 259:1. So enough info to suggest that the bigger guns generally do much better.



Here we have a situation were hits by the main armament were definitely more accurate even when both had the same firing platform. Something above and beyond the firing platform caused this disprepancy. The German 5" Guns (actually a 5.9" weapon) had a rate of fire of 6-8 rounds per minute, the main armament 2-3 rounds.

Just as a side note - The Germans did not use dual purpose weapons for the most part. The 5.9" weapon were excellent surface to surface but useless as AA. They had 12 of the 5.9" weapons, and for AA 16 x 105mm, and 28 20mm-37mm barrels. Probably would have served the Bismarck better to have true dual purpose weapons, possibly could have prevented the torpedo strike that ultimately led to her demise. Still for her time though (1941) she had a pretty impressive array of AA weapons.

I understand though why the Bismarck had her 5.9" secondaries, and the Yamato had her 6.1" weapons. These were relatively high rate of fire and fast traverse for surface combat, but outgunned the standard 5". The biggest interwar fear seemed to be having your capital ships sunk by smaller faster vessels using torpedoes, be it destroyers or torpedo boats. And these mid-size weapon were excellent for that purpose.


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## Garyt (Nov 19, 2014)

OK, a bit off track, largely due to me!

The year is 1930. From a carrier standpoint you have the Hosho, Akagi, Kaga, Ryuho is in progress, the Hiryu/Soryu are maybe on the drawing board, the Shokaku class are probably not that far along.

Battleships - You have the 4 old battleships from the Fuso and Ise Classes, the 2 Nagato class, and the venerable 4 of the Kongo class. The Kongo class had had it's first modernization, other than that no modernization of the battleships.

Cruisers- the old Furtaka class is around, the Takao and Myoko classes are pretty well built out, and the Mogami's were being started, and the Tone class was maybe on the drawing board.

From a destroyer standpoint, you have the Mutsuki's, and old style class, and the the first of the new style destroyers withthe first power and weatherproof 5" turrets. All the rest of the destroyers had not been built yet.

Fighters are experimental mono-wing prototypes at this point, the Zero and the Claude are far in the future. Your attack craft is the B2M1, fresh in production with a speed of 132 knots, but it could carry 800kg of torpedoes or bombs.

At this point, what do you do? Here is a summary of a few things I mentioned, maybe a few other ideas.
1) Scrap the idea for the Yamato class, funnel this money into carrier development
2) Perhaps scrap the Fuso's and Ise's - I'm not sure what this would get you but even if it's maybe 20% the cost the vessel it's worth it.
3) Nagato's and Kongo's - continue with modernization, look at also ugrading the Nagato's power plant to give them the speed to keep up with the carriers, and least the Kaga and Akagi
4) Research an alternative torpedo for the deck stored torpedoes on the Heavy cruisers. Something less volatile than the type 93's.
5) Destroyers - these were excellent vessels for the most part. the 5"/50 gun though that just came into production - make sure it has the traverse speed and elevation to be a true dual purpose weapon. If it requires more weight, increase the tonnage on future destroyers to accomodate this. This would dramatically help Japan's fleet AA needs. Also, soon as the 3.9"/60 is available, try to get at least 1/3 of the destroyers armed this way, having an "AA destroyer" to accompany the carriers would be the role they fill. And get started on the Matsu class sooner - it's not a technological issue that prevented earlier deployment of these, just an indifference to sub defense.
6) Aircraft - pay more attention to self sealing fuel tanks, armor, armored windscreens. An ideal early war fighter would be a zero but with armor and self sealing fuel tanks, and sacrifice range, much like the later A6M3 Type 0 Model 32 version of the Zero. Changing the 2 cowl mounted light machine guns to 2 wing mounted 12.7mm's would be nice to, and it's not a huge increase in weight.
7) Submarines - Focus on diving depth and speed instead of size. The large behemoth Subs the Japs had were of little use, though keeping them as sub tenders as an idea. From a doctrine standpoint, use them to attack shipping and pickoff the occasional damaged warship as opposed to looking at them as part of the battle line.
8 ) The 25mm cannon - hard to say on this one, as even by the end of the war the Japanese still though it was an excellent weapon. Maybe they were right to some degree, but loading procedures need to be changed to increase the practical rate of fire to the 240 instead of 120 RPM. And a more substantial mount for the triple version might be needed to better handle the recoil/vibration. Getting a license or even ignoring patents to make the 40mm Bofors would be nice, but first they have to realize their 25mm is not up to par.
9) Depth charges - Pay attention to other navies and use the K-gun and Hedgehog or at least something similar.
10) Radar - research, beg, steal, spy, but make sure you are close to on par with other countries radar technology by the start of the war.


Another though as well - Pearl Harbor. It might actually be better to not attack Pearl and lure the US Fleet to battle to protect the Philipines. If they respond early in the war, say by first quarter of 1942, you will have a lot of advantages. Draw them close enough to the Philipines and your land based air will support you. The US AA capability by this time is nothing special. And the vessels, if sunk go to the bottom of the Ocean and are not repairable at Pearl. Given the ability of the aircraft, the quality of the pilots, and giving the Japanese 6 fleet carriers with the possible support from land based air and I'll take that any day over what the US fleet can do with maybe 3-4 carriers and Battleship Row. Just don't overcomplicate things, and keep your battleships with your carriers so they can help with AA fire. 



If you happen to have the foresight at this point that these fragile airplanes that


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## parsifal (Nov 19, 2014)

I think the better hit rate by heavy guns has a lot to do with the inherently greater stability of the firing platform, plus the better accuracy of the range finding and fire control gear, whether it be radar assisted or purely optical, in the capital ships.

But even with all the accuracy in the world, actually hitting something at sea was to a big extent, a matter of luck, and luck increases the more times you get to roll the dice. Hence rof is a major determinant of hitting something


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## Shortround6 (Nov 19, 2014)

Part of the problem with scrapping and alternate construction were the different naval treaties. The Japanese did the best of any nation by far in hiding things, Like the Yamato construction but they weren't ordered until 1937. 
Different classes of ships had different restrictions and the big 5 were watching to see what each other were doing. 

Rebuilds could only be done on the oldest ships first and there were restrictions what was _supposed_ to be done. Scrapping ships she didn't have to after fighting tooth and nail to keep them in the early treaty talks would have raised a few eyebrows. 

Once Japan pulled out of the treaties all bets are off but that was not until the mid 30s and now you run into dockyard capacity problems, you can only rebuild so many old ships and build so many new ones at the same time.


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## Shortround6 (Nov 19, 2014)

parsifal said:


> I think the better hit rate by heavy guns has a lot to do with the inherently greater stability of the firing platform, plus the better accuracy of the range finding and fire control gear, whether it be radar assisted or purely optical, in the capital ships.
> 
> But even with all the accuracy in the world, actually hitting something at sea was to a big extent, a matter of luck, and luck increases the more times you get to roll the dice. Hence rof is a major determinant of hitting something



Yes, the big guns got the bigger rangefinders. Destroyers were _lucky_ if they got a 3 meter rangefinder (and one at that). Battleships often had 11 meter or larger rangefinders and multiple ones. They sometimes averaged results or at least use the 2nd and 3rd range finders as double checks.


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## cherry blossom (Nov 20, 2014)

For a small change to make some extra resources available, why not have the IJN not start any of its development of midget submarines? AFAIK, Japanese midget submarines damaged two ships with torpedoes during WW2, HMS Ramillies and the tanker British Loyalty, which was a terrible return for the investment made. As well as avoiding adding useless equipment to many I-boats that would free up Chitose and Chiyoda to be converted to aircraft carriers before WW2.

In addition, although a submarine with a high submerged speed Submarine No.71 - Wikipedia, the free encyclopedia was tested pre-war, the idea of fast submarines capable of independent operation was initially rejected in favour of the use of midgets. Without the midgets, might a quicker development of an I-201 analogue have been attempted? The problem with both No. 71 and I-201 is that they needed German designed Diesels for adequate range. In addition, I-201 used the German ST-52 steel formula and German welding methods for a strong and smooth hull. 

Unfortunately, I feel bound to add that the I-201 class were not ready for war by August 1945, so that making a choice to develop I-201 and purchasing the technology necessary from Germany in late 1938 (as soon as No. 71 had been tested), would leave it doubtful if the I-201 Class could take part in the early 1942 battles (OTL according to Wikipedia “The IJN General Staff made an official request for high-speed submarines in October 1943” I-201-class submarine - Wikipedia, the free encyclopedia).


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## parsifal (Nov 20, 2014)

Ah not correct. IJN midget subs were involved in at least 9 operations that I know of. Success was patchy, but then all of the major powers that developed midget subs experienced similar problems. They were essentially nuisance weapons, and in this, IJN midgets were about as successful as any of their contemporaries. 

A really good source to get to know IJN midget sub operations can be found here

Imperial Submarines

As an example of the Midget sub operations of the Jpanase, I can cite many instances of their use, but one will suffice to illustrate

"Guadalcanal. At 0255, I-16 launches Lt ( j.g.) Hoka's midget submarine HA-10 about 3,000 yards NE from Lunga Point. At 0816, after penetrating a screen of destroyers, HA-10 fires one torpedo and damages Cdr (later Rear Admiral) James S. Freeman’s (USNA ’21) ALCHIBA (AK-23) that is starting to unload her cargo of aviation gasoline, bombs and ammunition. Freeman beaches ALCHIBA to avoid her sinking. She continues to burn for four days. After the attack, HA-10, Hoka and Inokuma go MIA. I-16 returns to Shortland".


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## cherry blossom (Nov 20, 2014)

parsifal said:


> Ah not correct. IJN midget subs were involved in at least 9 operations that I know of. ...snip..


Mea culpa! I apologise for not thinking beyond the initial Japanese advance. By looking through the details on the Combined Fleet site, I tried to make a list of the midget's successes. However, I do take the point that their main value may have been the need to guard against their attacks.

During the Guadalcanal Campaign, two USN ships, Majaba (AG-43) and Alchiba (AK-23) were damaged (Alchiba clearly very severely although she was repaired), whilst in the 1944-5 Philippines Campaign, the destroyer USS Renshaw (DD-499) was also torpedoed and damaged. In addition in the Philippines, the dock landing ship USS Shadwell (LSD-15) may have been torpedoed and SS Oliver Kelly was hit by a torpedo which did not explode. Finally, off Okinawa the destroyer USS Halligan (DD-584) was torpedoed by HA-67 and sunk. This seems to be the only clear sinking by the midgets although the tanker British Loyalty was damaged beyond economical repair.

I still think that the same design effort aimed at high speed submarines would have produced a greater return.


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## parsifal (Nov 20, 2014)

For sure, but it was Japanese submarine policy rather than equipment that was the problem. The best printed account of Submarine Operations that I know of is Carl Boyds and Akihiko Yoshidas book "The Japanese Submarine Force and WWII" by Bluejacket books. Western histories portray the Japanese submarines as not attacking Allied merchantmen, which isnt true. They would attack, and for about half their missions, they engaged in dedicated antishipping operations. in 1942, the 50 something strong submarine fleet sank more than 1 million tons of allied shipping.

But it was not a dedicated German style campaign centrally focussed and co-ordinated like the German effort, and significant resources were wasted on frivolous and often dangerous operations. Without a doubt the greatest waste of resources were the re-supply efforts and nuisance raids that were mounted. Fleet co-operation was the forte of Japanese submarines, but results were a poor return for the investment. Simply learning the German methods would have yielded the japanese a much better return for their submarines.


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## Wavelength (Nov 23, 2014)

> In the Barents Seas battle 31st Dec 1942, Hipper struck again hitting 3 times with 120 shells, crippling the destroyer HMS Onslow.




The data in this case needs to be looked at more closely. Hipper first opened fire on the Achates at 0940 hours from a range of 14,900 meters (beyond visual range at the time), scoring a hit with its first salvo. However, its forward radar was knocked off line for about 50 minutes by a short in the ships power supply, and it ceased fire after only a few salvos. For the next 30 minutes or so it fired only few salvos in Kummetz’s efforts to keep the British destroyers engaged with the Hipper, while turning the convoy into the guns of the Luetzow force approaching from the south. Then at 1016 hours the Hipper turned to bring its aft radar to bear and opened fire on the Onslow from 12,000 meters scoring four direct hits with an expenditure of only 48 rounds. Hipper then expended 51 rounds on Bramble for an unrecorded number of hits. At 1117 hours it opened fire on the Achates once again, from a range of 17,700 meters scoring a hit once again with its first salvo, followed by two more direct hits and several near misses in the next few minutes. Achates would later sink from the damages. Shifting fire to Obedient Hipper hit it and near missed it from a range of 11,600 meters. That’s 9 direct hits that should be credited to Hipper during the battle. 

If we look at the firing in segments it scored 4 direct hits on Onslow at night for the expenditure of only 48 rounds which is equal to only 6 broadsides. It scored 3 direct hits on Achates, from enormous range for 8” at night, with a like number of salvos fired. It almost scored one hit for each salvo fired each time it opened a dedicated fire using its radars. 

Breaking up the firing into segments can give a better view of the hits scored per rounds fired at a given range, than looking at total rounds fired during the entire battle, because the ranges may vary and the condition of the ships firecontrol equipment can also vary greatly. For example, Exeter scored two hits on Graf Spee from a range of 19,400 yards by its third and fourth salvoes, or two hits per 18 rounds fired, or one hit for two salvoes fired. That is remarkable shooting, especially considering it had no radar, albeit the visibility was excellent. Then the Graf Spee started hitting the Exeter knocking out its turrets and it firecontrol and the ships command and control systems. Exeter scored no more hits despite a large expenditure of ammunition. Likewise Graf Spee’s shooting was very good; scoring 7 direct hits and three damaging near misses on the Exeter alone during the first 15 minutes of the battle. Once Graf Spee lost its radar and its foretop rangefinder things changed, however.


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## parsifal (Nov 24, 2014)

Dont agree. The statistics presented are raw statistics and ought not be skewed by selective editing of this kind. German gunnery had a reputation for being very good, and that is reflected in the statistics already. If we start selecting the statistics like that, the purpose behind them is lost or prejudiced by our selective editing. If we are looking for average rounds per hit, we have to look at the whole package, and not go looking for the statistics that might make our favourite ship or nationality present in a better or ideal light. 

There are instances that I know of where the British scored 1st salvo hits as well, but selecting statistics in that fashion will just serve to skew the overall results, and only serve mostly a propaganda purpose. Thgis discussion is not about the ideal, or the worst for that matter, its about total rounds per hit. For that we have to look at eveerything

The intent of these statistics was to show, in as complete a fashion as possible, how many rounds were fired per hit. 

With regard to ranges, they will only vary firstly if one side has a speed advantage, or both sides are either trying to open the range, or conversely close the range. If the both sides have similar speed, and they have opposing range objectives (ie one wants to close and one wants to open), overall, there will be little or no effect on battle ranges). This is effectively what happened at north cape. Once Scharnhorst determined she wanted to disengage, it took a long time for her to open the range, because DOY was trying for the opposite

There are also conflicting reports about the number of hits actually achieved. these results appear to be based on German Admiralty after action reports, which by then were under considerable political pressure to produce a report in the most favourable terms. British admiralty after action reports do not corroborate these numbers of hits at all, although the RN admitted the loss of the MSW HMS Bramble, which is not even mentioned in the DKM report.

In other words, German records for this battle, as far as damage to enemy are concerned, cannot be relied upon.


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## Wavelength (Nov 24, 2014)

They are actually compiled from the British reports.


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## Garyt (Nov 24, 2014)

> I think the better hit rate by heavy guns has a lot to do with the inherently greater stability of the firing platform, plus the better accuracy of the range finding and fire control gear, whether it be radar assisted or purely optical, in the capital ships.



As it has been shown, hits by the secondary armament from capital ships (usually 5" guns)was very poor as well, so the firing platform, while certainly a plus for big capital ships is not the answer as to why the 5" weapons had a lower hit rate.

As far as range finders go, the taller range finders on capital ships were for the main armament. Their secondary armaments used smaller range finders that were more akin to what you would find on a destroyer.

So, due to the lower accuracy of 5" guns on capital ships, and the facts above, you really cannot tie inaccuracy of 5" guns compared to cruisers or battleships main armament to the better firing platform and fire control.



> But even with all the accuracy in the world, actually hitting something at sea was to a big extent, a matter of luck, and luck increases the more times you get to roll the dice. Hence rof is a major determinant of hitting something



Equating hitting a ship to getting lucky on the dice is inaccurate.

Let's look at a 9 gun Cruiser. It with a salvo at 30,000 yards, gets a correction based on fall of shot, continues this for a few salvos and hits on the 4 salvo. This is about a 5 minute process to allow for fall of shot and adjustment. Was this because one of the shots "got lucky"? or was this a series of "educated guesses" if you would that were driven closer to their target by corrections of observed fall of shot?

I'd definitely say these were "educated guesses". When you have one moving ship trying to hit another moving ship miles away, and when you have to figure in things not covered by the firing solution, such as mount dispersion, there is indeed a bit of luck involved with hitting another vessel. But, it is not just a blind sot in the dark or a lucky roll of the dice. Feedback from fall of shot is crucial, which is why "straddling" a ship was so important. And repeated shots at a vessel will generally get closer and closer.

And in the above cruiser, 36 shots were fired for one hit. Does not sound great, but when you look at it as salvos instead, you have 4 salvos fired for one hit, and it is more common than not to only hit with one round even if 8-12 are being fired in a salvo.

To extrapolate it all to be a "lucky roll of the dice" and where firing as money shots as possible is not doing it proper justice. 

Now, this heavy cruiser could fire as fast as it's capable of. That would be about 17 salvos, or 153 rounds. But I doubt you are increasing your chances of hitting, as you are only getting correction every 4 salvo or so. There is a reason why the fall of shot was waited for before firing the next salvo. And either all navies had this wrong, meaning that firing as many salvos if possible instead of waiting for fall of shot to correct, or your opinion on this matter is incorrect.

Now, it seems when ship got closer the rate of fire intensified. To what degree I am not sure, but it very well became faster than the time needed to fire, spot, correct, and fire. But this was at much closer ranges where the chance of hitting was much higher.


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## cherry blossom (Nov 24, 2014)

An apparently minor thing to do differently would be the development of aircraft carrier catapults. In 1934-5, Kaga was fitted with the only IJN design to be tested. I have heard a rumour that the design started from those already used to launch sea planes and that, unfortunately, the designers missed the subtle difference that, while sea planes need a trolley to carry them, the aircraft carried on a carrier have wheels. Thus the catapults on Kaga were launching the aircraft from trolleys rather than just pulling them. I suspect that they may not have been flush with the deck. Jon Parshall gave some information in an old post elsewhere “Air Technical Intelligence Group (ATIG) Report #1, p. 3, mentions that air catapults were tried, but set aside as being "too complicated and unnecessary." ATIG Report #5, page 6 describes a catapult fitted (presumably on Kaga) in 1935. It was compressed air, with hydraulic retardation, and apparently could reach a speed of 55 knots”.

If we want to go really over the top, why not replace possibly the World's worse catapult designers by the best (i.e. Colin Mitchell)? Instead of using gunpowder or compressed air, why not realize that high pressure steam would be available on most carriers and could allow aircraft to be launched at a fairly fast rate as steam could be produced faster than air could be compressed. Of course, the designers would still need to design a mechanism that did not lose too much steam per launch. 

Suddenly it is no longer so critical that Soryu, Hiryu, Shokaku and Zuikaku can run at 34 knots. What if we used Shokaku's machinery to drive two carriers at 28-9 knots? How would Coral Sea have worked out if the Japanese force had deployed four Centaur Class carriers Centaur-class aircraft carrier - Wikipedia, the free encyclopedia instead of the OTL Carrier Division 5? I suspect that a Centaur class ship without radar would cost about half as much as a Shokaku but I admit that the lack of a thick armoured main deck (127 mm ?) would create a potential vulnerability (only potential in 1942 as the USN didn't use armour piercing bombs until later).

Shokaku's hangars are longer than those of Centaur, partly at least because Centaur's catapults stop its hangar going too far forward, and partly because Shokaku is much longer than Centaur. Navypedia Shokaku aircraft carriers (1941) - Imperial Japanese Navy (Japan) gives the dimensions as “Upper hangar: 190.0x~20.0x4.8m, lower hangar: 160.0x~20.0x4.8m.” whilst the Centaur Class hangar is normally given as 274 ft. x 62 ft. x 17.5 ft. The comparison is misleading because, while Centaur has two 54 to 55 ft. long elevators at both ends of the hangar which are not included in the hangar length, Shokaku's three elevators are included in its hangar length. However, even after excluding the space lost to the elevators, Shokaku has more than twice the hangar floor space of Centaur because of its double hangar (which would have restricted Shokaku from using post-war aircraft because of its lack of height). 

Despite this, Shokaku was only designed to carry 84 aircraft, 12 of which were to have been stored as disassembled reserves. The RN planned to operate 42 aircraft from Centaur post war and those aircraft were much larger than 1941 IJN aircraft (the planned complement included, for example, Sea Hornets). Again it comes down to being able to launch with catapults. Aircraft can be parked on Centaur's deck because less space is needed to fly them off. It seems likely that 60 A6M2s, D3A1s and B5N2s could be operated from a Centaur without too many problems (apart from strengthening the aircraft for catapulting). There is a last point that Centaur had space for about 800 tons of aviation fuel (in service, 349,000 gallons of AVCAT AVGAS) in better protected tanks than Shokaku, which could only carry 500 tons (doubled to 1,000 tons for Taiho). 

A nice feature is that you are now producing a cheap but effective design and can simply go over to large scale production when you realize that you need more. 

For a related idea, OTL Japan laid down four training cruisers and completed three. Those weren't very useful in a war but at least they were cheap. Could Japan have chosen to build two very basic carriers with the idea of using the hangars as class rooms in peace time for training command? Probably they would want a few anti-submarine vessels as well, so that they could also teach cadets to run Diesel engines.


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## Wavelength (Nov 24, 2014)

Garyt said:


> There is a reason why the fall of shot was waited for before firing the next salvo. And either all navies had this wrong, meaning that firing as many salvos if possible instead of waiting for fall of shot to correct, or your opinion on this matter is incorrect.
> 
> .



This was not the doctrine of the USN for cruiser fire and part of the reason why USN cruiser shooting was so awful. The USN adopted the doctrine of shooting as rapidly as possible and walking their salvo pattern back and forth over the target. USN cruiser shooting is remarkable for how poor it was. Didn't matter if it was day or night or with or with out radar-it was terrible. Walking salvos also spilled over into battleship shooting practices as well.


Apparently the Hipper was practicing more deliberate fire methods.

The best chances for scoring at least one hit from a straddling salvo occur when the range has dropped to about 60% or less the max ballistic range of the guns.


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## Garyt (Nov 24, 2014)

Interesting thought, Cherry Blossum. Sounds like you are saying is the need for the Japanese fleet carriers size was largely due to the need of having a long enough area for takeoff?

Another very minor alteration to the carriers that would have helped - open hangars. An open hangar allows planes to warm up down below, allowing a quicker launch. It also makes it easier to jettison ordinance off the side of the ship in the event of a fire. Explosions on the hangar deck would be contained less, which is a good thing, the explosion can vent itself to the open air easier than if it is contained more in a closed hangar design. It also allows other ships to assist better when it comes to fighting fires, and allows the hangar deck to aerate easier to avoid explosions from built up avgas vapor, such as what happened to the Taiho. And yes, you can have an armored deck over open hangar construction if you wish.



> I suspect that a Centaur class ship without radar would cost about half as much as a Shokaku but I admit that the lack of a thick armoured main deck (127 mm ?) would create a potential vulnerability (only potential in 1942 as the USN didn't use armour piercing bombs until later).



It did not take AP bombs to penetrate an unarmored deck - GP bombs would generally explode on the hangar deck of an unarmored carrier. And a bomb exploding on the Hangar deck was generally what was so damaging to aircraft carriers, happened to the Akagi, Kaga and Soryu at Midway and to the USS Franklin and Bunker Hill later in the war. The Japanese without radar did not know US bombers were coming, and with the Franklin and Bunker Hill the US did not want to shut down flight operations everytime a few bogies were detected on radar. 

Only Japanese Carrier to have an armored deck was the Taiho, and the US to my knowledge did not have an armored deck carrier comissioned prior til war's end, only the Midway about 8-10 days too late.

And with an armored flight deck, even most armor piercing or semi-armor piercing bombs would not pierce the deck when dropped at dive bombing altitudes. Depends a lot on the thickness of the deck of course and the type of bomb.


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## Garyt (Nov 24, 2014)

> This was not the doctrine of the USN for cruiser fire and part of the reason why USN cruiser shooting was so awful. The USN adopted the doctrine of shooting as rapidly as possible and walking their salvo pattern back and forth over the target. USN cruiser shooting is remarkable for how poor it was



Interesting Wavelength, and that makes sense. I was not aware that anyone would rapid fire from range - I knew as they got closer they would, but not from range. How about US destroyer practices? Same as US Cruiser practices?



> and part of the reason why USN cruiser shooting was so awful.



That's my point - firing as fast as you can without receiving corrections has a strong negative effect on accuracy. It also cause crew fatigue, but that's a different matter.



> The best chances for scoring at least one hit from a straddling salvo occur when the range has dropped to about 60% or less the max ballistic range of the guns



So about 18-19k yards for a cruiser? I would think though the initial attempts and keeping the vessel under fire starting at longer ranges would help, as long as you are within rangefinder range (or if radar is effective)?


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## parsifal (Nov 24, 2014)

Wavelength said:


> They are actually compiled from the British reports.



No, they are not. you might think they are, but I have the final report submitted to the Admiralty, and it reads nothing like the account you have posted

The following is a summary of the report submitted to his Lordships...

"At 08:20 on 31 December, OBDURATE, stationed south of the convoy, spotted three DKM DDs to the rear (west) of the convoy. Then, ONSLOW spotted DKM ADMIRAL HIPPER, also to the rear of the convoy, and steered to intercept with ORWELL, OBEDIENT and OBDURATE, while ACHATES was ordered to stay with the convoy and make smoke. After some firing, the British ships turned, apparently to make a torpedo attack. The Destroyers were heavily outgunned, and Sherbrooke knew that his torpedoes were his most formidable weapons; the attack was feigned as once the torpedoes had been launched their threat would be gone. The ruse worked: Hipper temporarily retired, since Kummetz had been ordered not to risk his ships. Admiral Hipper returned at around 0900 to make a second attack, opening fire on the ONSLOW and eventually hitting after about 30mins of continuous shelling causing heavy damage and many casualties including 17 killed. Although ONSLOW ultimately survived the action, Sherbrooke had been badly injured by a large steel splinter and command passed to OBEDIENT.......

HIPPER then pulled north of the convoy, stumbled across BRAMBLE, a Halcyon-class MSW, which opened fire; HIPPER returned fire with her much heavier guns. The DD ECKOLDT was ordered to finish BRAMBLE off, (she sank with all hands) while the HIPPER shifted target to OBEDIENT and ACHATES to the south. ACHATES was badly damaged after about 10 minutes of action, but she continued to lay down smoke until she eventually sank. (The trawler NORTHERN GEM rescued many of the crew of ACHATES.)...."

So, the inconsistencies between your version and the admiralty report are numerous. Hipper did not fire on the Achates initially...Achates was not even in the initial attacking group. hipper scored no hits in her opening salvo, in fact she was in action for more than thirty minutes before any hits were achieved against the Onslow and a further 10 minutes or so before hitting Achates.


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## Wavelength (Nov 24, 2014)

> So, the inconsistencies between your version and the admiralty report are numerous. Hipper did not fire on the Achates initially...Achates was not even in the initial attacking group. hipper scored no hits in her opening salvo, in fact she was in action for more than thirty minutes before any hits were achieved against the Onslow and a further 10 minutes or so before hitting Achates



Indeed, but that doesn’t mean I’m wrong. The British summary is bare bones and with due respect I think your reading in your own conclusions on not enough information. The hit totals come from the British damage reports and they total at least nine direct hits. That’s a hard fact. 

By combining reports from several sources we get a better idea of what happened. We know from the Hipper KTB when it fired at what targets, how many rounds it fired, and from what ranges. There is no reason to doubt those facts. Other British reports confirm those facts. For example, Achates survivors report that Achates was indeed hit by Hipper’s first salvo at 0940 hours: 



> “The enemy picked us out for his early fire. We must have been conspicuous. The German cruiser got us the first time.”


 (War at Sea pg 267)

The range was 14,900 meters which must have been correct because it yielded straddles and a hit. Hipper indeed retired after opening fire on Achates, but not because of feinted torpedo attacks, like how appeared to the British, but because the blast from Hipper’s guns disabled its IFF equipment and its forward radar. 

Hipper wasn’t banging away for 30 minutes at the Onslow. If that was the case it would have expended most of its ammunition. “Between 1001 hours and 1016 hours Hipper fired only one salvo” Only at 1016 hours did it take the Onslow under fire. It expended only 48 rounds during this firing episode. Onslow was hit four times for those 48 rounds. That’s a fact confirmed by British damage reports. The range was 114hm.

The Hipper expended 51 rounds on Bramble. 



> At 1115 hours Achates had just cleared her own smoke when Hipper reappeared to the northeast. The cruiser opened fire from 14,000 yards and hit with her first broadside


 (O’Hara)



> Hipper meanwhile closed the convoy and sighted its escorting destroyers once more, catching Achates unprotected by smoke screen. Hitting with her first salvo, the German Flagship quickly reduced the destroyer to a shambles killing or wounding many of her company, including her captain, and leaving her on fire with a serious list.


 (Whitley) 

Are O’Hara and Whitley both wrong?

The hits on Achates at that time were three: the first to the bridge, the second through a boiler room and a third through the forecastle. Those are facts from the British side.

The Hipper opened fire the second time on Achates at 1117 hours from a range of 17,700 meters. That must be correct because it was the correct range in order to produce the hits recorded.

It was 1124 hours when Hipper took Obedient under fire. Obedient’s wireless station was destroyed.

Fleshing out those bare bones tells how deadly accurate Hipper’s shooting was that polar night.

Concerning the reliability of the German records, Krancke in 1958 questioned if Kummetz had manipulated the KTB concerning the reminder from Kluber to avoid risks, which Kummetz used to justify retiring from the battle whith a vastly superior force. But that is all it entails and it’s irrelevant to how Hipper was fighting.


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## parsifal (Nov 25, 2014)

I will deal with the Onslow issue a bit later in a separate post For now, I have open in front of me the after action report for HMS Achates 



> Are O’Hara and Whitley both wrong?



In the case of the Achates, unfortunately yes. See my comments below. 



> The hits on Achates at that time were three: the first to the bridge, the second through a boiler room and a third through the forecastle. Those are facts from the British side.



Nope. Relying on the best primary record that there is, being the official after action report that followed a board of enquiry , she began to take fire from the hipper at 0940, which in that initial encounter lasted until just before 1000. There were no hits, but there was one very near miss that caused casualties and peppering of the upper hull. 



> The Hipper opened fire the second time on Achates at 1117 hours from a range of 17,700 meters. That must be correct because it was the correct range in order to produce the hits recorded.



That's about right but there are some details that suggest it was not the first salvo that was the hit on Achates. The after action report states that she took fire again from just before 1115....say approximately 1114. after 3 mins she was hit....ie, not on the first salvo. Its common for crewmen to say things like 'we were hit from the first salvo". Frankly, they are not in a position to know....The CO and the bridge staff would have been the only people I would rely on for accurate reports....we don't have that in this case, since the entire bridge was killed with the first direct hit, but we do have the next best thing, being the Admiralties after action report and the board of enquiry's report, which are not quite the same, but which are near enough.

Article 15 of the board of enquiries findings statges:

"


> This she proceeded to do, but just prior to 1115, again came under accurate enemy fire from the hipper and in spite of increasing speed and zig-zagging, received a direct hit on the fore end of the bridge at about 1118 which killed or seriously wounded all bridge and wheelhouse personnel, except the Yeoman and the Coxswain, and put B Gun and its crew out of action. A cordite fire was started on B Gun Deck but was soon put out by the seas, which came over the forecastle as the ship turned into the wind


".

So the first hit was at 1118, after three minutes of firing, on a ship that had had its speed reduced to 20 knots. Hipper's shooting is not looking so hot now.....

Article 19 of the report gives the details of the second hit. there is no time given, but judging by the events that transpired between the first and second hits, id say about 5 to 10 minutes. It appears that against a target now reduced to 12 knots the Hipper, after at least two more salvoes achieved one more hit. The report is silent on the total number of salvoes hipper fired 



> 19 The ship was straddled on two more occasions before the firing ceased, and received direct hit in the Seamen’s’ Bath Room port side and a near miss abreast No.2 Boiler Room



So, at the end of this, after 30 minutes of firing there are 1 near miss and two hits, one hit whilst the ship was travelling at 20 knots, and another hit whilst travelling at 12 knots. That's nothing to crow about for Hipper 



> Fleshing out those bare bones tells how deadly accurate Hipper’s shooting was that polar night


.

The board of enquiry's findings were, with respect to Hippers shooting accuracy...



> Enemy fire appeared very accurate for line but spread for range averaged 400 yards. Near misses caused more extensive damage to the hull than actual hits. All shells were H.E. and burst on impact, but caused no serious fires.



Good shooting but not I wouldn't say outstanding given the vulnerability of the target.


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## Wavelength (Nov 25, 2014)

Well at least you are seeing the close correlation between the British reports and the German reports and timeline now. The British reports support the German reports and the German reports support the British reports. Not exactly identical, but that is typical. 



> The report is silent on the total number of salvoes hipper fired



Right. We must get that from the German side. I have that right here. It fired five 4 gun salvos at three different targets between 0940 and 1016 hours. It fired six 8 gun salvos at Onslow between 1016 and 1018, scoring multiple hits two minutes. That is really excellent shooting there. 

It fired about 12 four shot salvoes at Bramble scoring an unknown number of hits between 1036 and 1040 hours. That the Bramble was hit multiple times is known but we have no number for the hits scored.

It opened fire on Achates at 1117 (not 1114) and ceased fire at 1118, switching fire to Obedient at 1124 hours. Flashes were observed through the mist at the time of the fall of shot at 1118 hours. Considering the time of flight for almost 20,000 yards, that hit was probably from the first salvo. Now we see that Whitley and O’Hara were probably correct and what they are basing it on. These few salvos had to be only 4 shot salvos because Hipper was firing over her bow making 30+ knots.

Excuse me, but that is excellent shooting by any measure. Factor in the conditions of fog, snow, and the polar night, and it is SPECTACULAR shooting. It is rather unprecedented shooting for cruiser shooting during WWII.


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## Wavelength (Nov 25, 2014)

Garyt said:


> So about 18-19k yards for a cruiser? I would think though the initial attempts and keeping the vessel under fire starting at longer ranges would help, as long as you are within rangefinder range (or if radar is effective)?



Yes, accurate ranging finding through rangefinders or radar doesn't change the ballistics, the danger space, or the salvo spread. Therefore radar ranging and spotting do not improve the probablity of hitting from a straddle at a given range.


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## Garyt (Nov 25, 2014)

Not sure what you are saying here, Wavelength?


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## Wavelength (Nov 25, 2014)

Only that radar or larger range finders ect.. won't help the probability scoring hits at longer range from a straddle. Having more salvos to spot and correct from would probably help to obtain more straddles more quickly though.


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## Garyt (Nov 25, 2014)

Gotcha. 



> Having more salvos to spot and correct from would probably help to obtain more straddles more quickly though.



Problem is, the the rate of fire of 8" and smaller weapons, depending upon range, can't be met if getting corrections from every salvo, obviously the flight time is too long.

I found it interesting, the US Navy practice of when range gets too short of only spotting for one out of every X salvos, as spotting for every salvo becomes too confusing when you have multiple salvos in the air.


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## parsifal (Nov 25, 2014)

> Excuse me, but that is excellent shooting by any measure. Factor in the conditions of fog, snow, and the polar night, and it is SPECTACULAR shooting. It is rather unprecedented shooting for cruiser shooting during WWII.



Your version shows significant difference to the RN version, as is your claim that hipper turned away because of an equipment failure. That's something that would have resulted in a court martial in the RN if true. It smacks of extreme timidity and a lack of understanding about what needed to be done, but then the RN was not saddled with impossible terms of engagement. I still am not convinced the Hipper disengaged because of own equipment failures. Maybe that was something that happened, as an incidental event, but I will bet the farm she turned away because of a fear of torpedo attack. Somewhere there will be the German Admiralty after action report that details this. Annapolis have the german admiralty situation reports for most months, translated to English in 1948, and now available on line. Ill see if I can locate the report for Hippers action on that day.

There are obvious and serious differences between the RN account, and yours that makes the difference between miraculous shooting, that no-one, of any nationality, except hipper apparently, could ever achieve, either during the war, or after that Im aware of, and just good to average shooting. there are massive differences in the times for shooting as well. If Hipper was shooting so well, it make one wonder why she didn't despatch the RN cruisers rather than take three hits, fumble then drop the ball, then run like a girl as she did. No, as you can see, I am not impressed with hippers performance, and, as you can see, Im one of those sceptics that beg to differ about the quality of her shooting that day


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## parsifal (Nov 25, 2014)

Found it. 

Kummetz's log entry pertinent to this issue, states in plain language...(English translation).. "*Only quick action can solve the problem of danger from torpedo attacks and this has to be considered in the light of my orders not to take any serious risks*."

He did not withdraw because of equipment failure. He withdrew, in his own words and judgement because of the very real and justified, fear of a torpedo attack from the British destroyers......


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## parsifal (Nov 26, 2014)

For all the bluster about exceptional gunnery by Hipper, the Germans had precious little to show for it. The convoy escaped unharmed, Sherbrookes command had been roughly handled, with two ships lost, both of which at the tie they were hit had top speed of below 20knots. To be fair, Hipper had completed its part of the mission.....the distraction of the RN Convoy escort,...very efficiently, though I would stop well short of describing anything the hipper (or any of the other german ships that day) as outstanding. 

Captain Stange of DKM CS LUTZOW wrote in the ships Log as the German ships were running for port that day as 
"


> As we withdraw from the battle scene, it is hard to escape the feeling that, even though the situation appeared to be in our favour, we were unable to get at the convoy and scored no successes whatsoever


." He was on the money there, and wasn't trying to argue how well they had done. Most people understand Barents Sea as a defeat for the Germans that they should have won but didnt


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## Wavelength (Nov 26, 2014)

> Somewhere there will be the German Admiralty after action report that details this.



I have it right here. It is the SKL analysis of the radar equipment performance. It says that the first salvo’s blast tore the IFF device from its mountings and destroyed it. It says this forced Kummetz to revise his attack plan which was to send in the destroyers while supporting them with artillery fire from the Hipper at a distance-keeping the cruiser out of torpedo water. IFF was essential to this plan considering the conditions. Without IFF Kummetz was obliged to recall his destroyers and attempt to achieve his goal of diverting the close escort and turning the convoy into the Luetzow group with artillery fire alone. The Hipper as you correctly say performed this part of the overall battle plan. This was despite the difficulties of having its forward radar off line for almost an hour, and the aft radar operators needing to phone in the targeting data to the firecontrol computer room, instead of by data link, because the electronic connection in the computer room was faulty. That is all right in the report.

The plan failed because Stange dropped the ball, not the Hipper. Luetzow and its destroyers had the convoy in a perfect set up, with the convoy ships on radar at 1030 hours. But Stange did not attack because he could not identify them visually. He froze up, being afraid of a friendly fire accident. His IFF was switched on and working but he ignored it. He could have sent in his destroyers and kept track of them while supporting them with 11” gunfire because he had functional IFF, but he didn’t. These are all pointed out the SKL analysis. Stange is strongly criticized for not using his electronic IFF and opening radar directed fire. It points out that Luetzow’s radar performed exceptionally well in directing blind fire later on though, which made Stange’s freeze up all the more disappointing and frustrating. It recommends that electronic IFF always be given priority over visual identification in the future. 

You are entirely correct that Kummetz was concerned about not exposing his cruiser to possible torpedo attack in general. Kummetz was bound by the German fighting instructions which forbad exposing major warships to possible torpedo attack at night. As Kummetz himself wrote, since it was night 24 hours a day that time of year he was bound by these instructions. Kummetz handled his cruiser far better than American Admiral Wright did four weeks earlier at the night Battle of Tassafaronga. Kummetz never intended to send the Hipper in so to speak. But to always keep it at a distance in the presence of enemy destroyers. This he did.

I completely understand being skeptical about the gunnery performance. I was myself before I discovered the documentation. The evidence is strong. It is perhaps the strongest argument in favor of radar directed fire control from the WWII record.


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## Wavelength (Nov 26, 2014)

Which brings up something the IJN should have developed, but didn't in time. Develop effective radar directed fire control for its warships.

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## parsifal (Nov 26, 2014)

Agre completely with the last post. we will just have to agree to disagree on the hipper issue. Despite the heat, it was a very good discussion, enjoyed it thoroughly....Hope you enjoyed the exchange as well


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## cherry blossom (Nov 27, 2014)

Possibly the most important change needed is to “sort out” the 4th Bureau of the Imperial Navy General Staffs. This is the section responsible for code breaking and communications. Almost everything in that section's area of responsibility was managed badly and to make matters worse, they helpfully advised the Foreign Ministry on their codes. 

Let us start by looking at Japanese codes (although the radios were another serious problem). We might despair looking at OTL history but before we simply assert that Japan was not able to produce good codes, it is worth noting that the Imperial Army's codes were significantly better than the Navy's and resisted Allied efforts until late in 1943. Of course, the IJA was taking to the Poles and Finns in the 1930s about topics of mutual interest, such as the USSR, and seems to have picked up a few ideas. 

Assuming that we do not have money to buy code machines for every IJN warship, let us imagine using standard 20-20 hindsight to teach us how to encode IJN communications starting from one day in about 1935. We start off with a new two part code book, which can be similar to that used in the code named by the USN as JN25 except that the codes are chosen randomly rather than being divisible by three. The code will be superenciphered using a separate book of random numbers but by 1940, such a code was vulnerable. Not only JN25 but also the Royal Navy's codes were broken by their enemies. The method of breaking the codes was called creating a “depth”. That means aligning a series of code groups from several received signals so that code groups superencipered by the same random numbers are aligned. The basic approach was to look for the appearance of the same numbers in two signals. For example, we might find the same common code groups at positions 5 and 13 of two signals. We can feel more confident that we are not seeing an accident if a third signal can be aligned to give the same number at positions 11 and 15 with signal 1 and positions 7 and 12 with signal 2. Card sorting machines could be used to look for such matches. The use of divisibility by three was particularly disastrous in JN25 because it allowed an alternative approach as even with non-carrying addition, the differences between two correctly aligned set of code groups would be slightly more likely to be divisible by 3. Poorly trained cipher clerks using the same or predicable sets of “random numbers” weakened codes further.

The IJA's method was to replace the process of non-carrying addition by the use of a “conversion square” Allied and Axis Signals Intelligence in World War II - Google Books or THE BREAKING OF THE JAPANESE ARMY ADMINISTRATIVE CODE and New evidence on breaking the Japanese army codes for the lucky few with access. They weren't perfect because they didn't encode which square was used for the message but the effect was that a codebreaker could only easily align messages superenciphered using the same conversion square.

In 1943, the Royal Navy had the same problem because it realised from its own Enigma intercepts that the Germans were reading its codes. They replaced their Number 3 cipher by their Number 5 cipher. The biggest change was that they introduced an adjustable grille invented by John Tiltman https://www.nsa.gov/about/_files/cryptologic_heritage/publications/misc/tiltman.pdf (page 45) so that only a subset of the random numbers on a page are used. Again the result is that only messages using the same grille setting can be aligned.

Now as those are independent improvements, my new IJN system uses both an IJA style conversion square and a Tiltman grille, which should keep any enemy codebreakers busy until 1945.

Apparently, I have just changed the details of the Pacific War without making any fundamental change. However, the diplomacy of 1941 was conditioned by American confidence. The fact that Japanese codes were known to be fairly weak must have led to the idea that “those monkeys aren't too bright”. If Japanese codes had been completely unbreakable since Yardley's revelations had been published, might American policy have been more cautious?


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## cherry blossom (Nov 28, 2014)

For my next move as Japanese Navy Minister or perhaps Chief of the Imperial Navy's Staffs, I intend to invite the Austrian actress Hedy Lamarr to visit me, naturally with all expenses paid from IJN funds. Oddly enough, I am not primarily motivated by her controversial performance in Ekstase (1933) Ecstasy (1933) - Synopsis with its nudity and simulated sex (try Bing image search for details) but by my feelings for her mind. I feel confident that the 4th Bureau of the General Staffs will be deeply impressed by the ideas of a young foreign woman on how they might improve their radio communications. To see what they might learn, you can listen to NPR Media Player.

I am not sure if the IJN would have been able to get frequency hopping to work in the 1930s. However, the spread spectrum idea is simpler. If you send the same energy on four different wavelengths instead of one, the noise on the four channels is independent and therefore the noise is only increased by the square root of four which is two. Thus the signal to noise ratio is doubled. Of course, we really want to use 64 wavelengths to give us a factor of eight in the signal to noise ratio.

Tanaka Raizo's article “The Struggle for Guadalcanal” in “The Japanese Navy in World War II in the words of former Japanese Naval Officers” edited and translated by David C. Evans has on page 210:
“Communication failures. Our communication system was seldom good, and during the fall and winter of 1942 it was almost consistently terrible. In wide theatres of operations and under difficult battle conditions it is indispensable for a tactical commander to have perfect communication with his headquarters and with his subordinate units. The consequence of poor communications is failure” 

We can add other examples such as the mangled message sending Carrier Division 5's aircraft against the Neosho rather than against the American carriers at Coral Sea to reinforce Tanaka's message.


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## cherry blossom (Dec 1, 2014)

Although my comments on the 4th Section of the General Staffs work haven't exactly sparked massive interest, I feel that I should discuss their most catastrophic failure. This was their helpful advice for the Japanese Foreign Ministry on codes. During the Thirties two cipher machines were designed by the IJN and then used for Japanese diplomatic codes. These were the Type 91 Alphabetic Typewriter, which was called Red by the Americans, and the Type 97 Alphabetic Typewriter, which the Americans called Purple. 

There is a description of Red at Development of the First Japanese Cipher Machine: RED, which concludes “Now, the RED cipher machine is remembered as a classic example of a weak machine cipher broken by codebreakers. There is even a view that the weak RED cipher provided a tutoring period for codebreakers to prepare themselves for more complicated ones such as PURPLE.”

The mechanics of the related machines called Purple, Coral and Jade are described at PURPLE, CORAL, and JADE. Whilst Purple was certainly stronger than Red, it was still not a strong cipher and it had fewer possible permutations than contemporary rotor machines as it was not possible to carry out an operation equivalent to swapping the rotors. However, the real errors that doomed Purple's security were the totally unnecessary choice of keeping the division of the alphabet into groups of twenty and six as with Red and the sending of the same messages using both the broken Red machine and the new Purple machine during the period when Purple was replacing Red.

Naturally it is very easy to suggest with hindsight how to do much better. For example, either the American ECM II The ECM Mark II, also known as SIGABA, M-134-C, and CSP-889 or the later Russian Fialka http://www.xat.nl/fialka/files/man001.pdf would have kept Japanese diplomatic messages completely secure up to 1945. However, a more realist question is whether there were options that Japan might have plausibly taken. One possibility might have been to buy an early Enigma A or B The Enigma A and Enigma B and make the rotor motion less predictable by making the cams adjustable.

Unlike most of the improvements suggested in this thread, keeping Japanese diplomatic codes secure might have very significantly altered history. There are possibly three mechanisms which all might have made a Pacific War less likely. 

Firstly, as mentioned earlier, secure Japanese codes might have caused America to take Japan more seriously as a potential adversary, which might have made American policy more cautious over 1941. 

Secondly and much more obviously, America would have listened more carefully to the Japanese Ambassador Nomura. Nomura, as a retired full admiral felt that he was in Washington to represent the IJN and to make policy and he was determined to avoid a war (see Peter Mauch's Sailor Diplomat http://www.h-net.org/reviews/showrev.php?id=34971). Unfortunately, when he diverged from his instructions from the Foreign Ministry, the Americans reading the often poorly translated instructions, believed that he was trying to deceive them. “Misunderstanding and Mistranslation in the Origins of the Pacific War of 1941-1945: The Importance of "Magic" by Keiichiro Komatsu http://theburmacampaignsociety.org/library/Lecture-by-Dr-Keiichiro-Komatsu-24-March-2002.pdf goes into more detail on the malign effects of poor translations.

Finally and most importantly, American leaders would have had to ask Ambassador Grew's opinion rather more often as he would be left as their best source on what Japan was likely to do. OTL, Grew's views were assumed to be wrong because he was naturally not informed of the results of code breaking and he was mostly ignored. Here is an extract from “My Year with Ambassador Joseph C. Grew 1941-1942 — A Personal Account” by Robert A. Fearey www.connectedcommunities.net/robertfearey/year_with_grew.doc : 
“Fully set out in those volumes are the arguments supporting Washington’s handling of the negotiations, on the one hand, and on the other, Ambassador Grew’s firmly held views that Washington’s stance was unimaginative and inflexible; that the Embassy’s carefully considered reports, analyses and recommendations, centering on Prime Minister Konoye’s proposal that he and President Roosevelt meet face-to-face in Honolulu in a direct effort to achieve a settlement of all outstanding issues, were given short shrift; and that if the meeting had been allowed to take place the Pacific War might have been avoided.”


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## Garyt (Dec 2, 2014)

Sorry about the no response, Cherry Blossum. That's what happens when you try to bring a thread back on track 

I think we had sidetracked into "The accuracy of WW2 Naval Guns"

But I'd fully agree that the code was a huge factor. Without a broken code for instance, the Japanese are not ambushed at Midway.

The one area it's not going to fix however is the industrial inequity of the 2 sides, as well the fuel inequity. 

But I'm sire you are aware of that, and very few of these solutions do anything to address these issues.

I wonder if not making the attack on Pearl in hindsight would be better for the Japanese.

If the US took the bait to defend the Phillipines, maybe the Japanese get their defining battle. THe US anti aircraft was not that much to write home about at this early stage, and the US battleships did not offer a ton of AA help before refitting. The Japanese would have 6 fleet carriers against 3-4 american carriers, and the Japanese Cruisers, Destroyers and even the Yamato would have a chance to do what they were best designed to do - a surface action against another fleet.

And perhaps with enough US losses, and no Pearl Harbor suprise attack as a rallying call, the US might be quicker to come to the bargaining table with the Japanese.


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## Wavelength (Dec 3, 2014)

The USN was also strapped for fuel during the first year or so. It took awhile to build up the fuel supply. The Japanese failed to go after the stock piles at Pearl when they had the chance.


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## Garyt (Dec 5, 2014)

> The Japanese failed to go after the stock piles at Pearl when they had the chance.



The old second wave debate. I'm not sure how I feel about that one, how many losses would a second wave at Pearl Harbor taken, balanced vs. the additional damage that could be done.

Heck, going after the fuel reserves might have been more important than Battleship Row. If you can render the US Pacific fleet inoperable for a few more months, it might be worth it.

I guess one big question, did the Japanese have accurate intelligence of where the reserves were in late 1941?

Overall, I'd say a second wave makes sense, other than the problem with Japanese being able to replentish trained pilots. Trained pilots might have been Japan's least expendable asset, ranking right up there with fuel.


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## Garyt (Dec 9, 2014)

Just had a thought run through my head.

The Japanese "Decisive Battle" plan revolved around what they thought they had learned at Tsushima, along with updates as technology updated.

What they really failed to learn though is that the Victory at Tsushima had much to do with logistics - without the Russian Baltic fleet having to travel thousands of miles, the result may have been different.

But in failing to truly take into account the importance of logistics in winning a naval war the Japanese shot themselves in the foot for their efforts in WW2


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## parsifal (Dec 9, 2014)

Issues about naval intell need to be put into perspective. The JN25 code was introduced just prior to PH and remained secure until the Tokyo raids in April. the flurry of signal traffic that followed that attack compromised the code, and the Japanese were very lax in not changing the code until AFTER Midway, by which time the Americans were reading about 80% of IJN traffic. 

After Midway, new code books were finally issued and Japanese signal traffic returned to a level of security...sufficient to give them victory at Savo Island. The USN was again plunged into signal blindness. That remained the case until the end of the Guadacanal campaign. USN remained ignorant of Japanese evacuation.

The key to successful intell was not some magic bullet (please pardon the pun), but resources. throughout 1943 and 44 the allies poured more and more resources into the code breaking efforts. by the end of 1943, there were nearly 40000 codebreakers hard at work working continuously on breaking IJN codes. tens of thousands more were at work on the Army codes. Like the Germans in Europe there was no effective answer to that. There was absolutely nothing the IJN could have done to secure its signal security after 1943. before 1943, they should have focussed on the basics....that is, changing the codes more regularly.

With regard to radar, it was a conscious decision by the IJN not to pour money into radar technologies. The problem for them was again a question of resources. Whereas in 1944, it was quite common for US warships to carry at least one radar, down to PT boat size, and for DDs to be carrying four or five radars, the Japanese were struggling to fit even one radar to even major warships. moreover by the time they realized its importance, the IJN was a full generation behind the Allies in terms of technical proficiency. Radar fitouts on ships remained very rudimentary and unsatisfactory, and training in operation very poor. it was the same situation with ASDIC.

The Japanese needed to work on their ASDIC techs, their ASW training and they absolutely needed an airborne EW radar . The other gunnery and FC radars would have been noice to haver but not essential.


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## cherry blossom (Dec 10, 2014)

parsifal said:


> Issues about naval intell need to be put into perspective. The JN25 code was introduced just prior to PH and remained secure until the Tokyo raids in April. the flurry of signal traffic that followed that attack compromised the code, and the Japanese were very lax in not changing the code until AFTER Midway, by which time the Americans were reading about 80% of IJN traffic.
> 
> After Midway, new code books were finally issued and Japanese signal traffic returned to a level of security...sufficient to give them victory at Savo Island. The USN was again plunged into signal blindness. That remained the case until the end of the Guadacanal campaign. USN remained ignorant of Japanese evacuation.
> 
> ...


I don't think that you have realized how stupid the IJN was with its codes. There is the issue of poor training. The additive tables of JN25B had 50,000 groups of numbers but 60% of the messages used the first 10,000 numbers as most clerks started on page 1 and as you mention they did not change the books often enough. 

There is no sensible justification for having each code group divisible by three. If a transmission or decoding produced an error, there was only a one third chance that the erroneous group would be divisible by three. However, if the group cannot be found in the code book, it is clearly an error, and even with the divisibility by three, it is still not at all simple to guess what the correct group should be as any of the five numbers could be wrong. Clearly the IJN was reaching towards error checking codes but they were nowhere near getting that idea to work. They were, however, making their opponent's task much simpler. For example, occasionally the clerk would forget to add the superencipherment. Such signals were immediately identifiable as all the groups were divisible by three. The more mathematical consequences are explained in “The Flaw in the JN-25 Series of Ciphers, II” by Peter Donovan http://carma.newcastle.edu.au/jon/Preprints/Papers/Submitted Papers/Walks/Dirks notes/09duc1.pdf. 

As we both agree, there was no way a simple superenciphered code such as JN-25 could have resisted the sort of effort used against it (and the slightly better RN codes also fell to the Germans). However, I believe that using conversion squares plus a grille with enciphered indicators would have resisted solution during WW2 with the same frequency of replacement of code books as OTL.


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## cherry blossom (Dec 10, 2014)

Garyt said:


> Sorry about the no response, Cherry Blossum. That's what happens when you try to bring a thread back on track
> 
> I think we had sidetracked into "The accuracy of WW2 Naval Guns"
> 
> ...snip...



I wasn't too concerned to bring your thread back onto track by suggesting bringing Hedy Lamarr to instruct the 4th Section about communications. I did like the discussion of the accuracy or otherwise of cruiser guns but didn't have much to contribute. The Hippers were significantly bigger and newer than most “Treaty cruisers” and I suspect that they had similar fire control apparatus to the Bismarck Class whilst for example American heavy cruisers (except the Alaskas) carried lighter, simpler and cheaper fire control equipment than the battleships. As mentioned earlier, Prinz Eugen matched Bismarck's shooting fairly closely at Denmark Strait which is impressive as Bismarck's shells had advantages such as being able to travel further under water and coming down less steeply. 

If one reads http://www.fischer-tropsch.org/prim...Reports/USNTMJ-200F-0023-0085 Report O-31.pdf, the situation with IJN cruisers seems to have been slightly different with most heavy cruisers and most of the older battleships having the older Type 92 fire control equipment. Only Hiei (used as test ship), Yamato and Musashi are stated to have received the Type 98 equipment but perhaps the Mogami and Tone classes may also have received improved equipment. Even the best may not have worked perfectly. According to page 40, the Type 98 giro horizon showed problems with hunting in the follow up and gimbal friction. Thus the Type 1 giro horizon was produced but only as a single prototype which performed well at sea on the carrier Shinyo. 

The anti-aircraft fire control http://www.fischer-tropsch.org/prim...Reports/USNTMJ-200E-0633-0764 Report 0-30.pdf showed similar problems of both performance and availability (see Enclosure E). While the Type 94 fire control was better than the Type 91, Nagato and Haruna were still fitted with the Type 91 in 1945 and there were apparently huge problems in producing enough Type 94 sets. In terms of what it did the Type 94 equipment was equivalent to the American Mark 37, and like it required rather a long time, 20 secs for the Type 94, to produce a solution. However, the American Mark 37 started to receive ranges from radar from late 1942 and the Royal Navy was already using radar ranges to improve its anti-aircraft accuracy in 1941 (RN equipment gave a quick and dirty answer rather than solving equations slowly and accurately like the Mark 37 or Type 94). One of the worse features of both the Type 91 and the Type 94 was that they depended on a separate optical range finder. When IJN ships came under attack by multiple enemy aircraft, it was discovered that nobody had realized pre-war that getting both the fire control telescope and the range finder to point at the same aircraft might be a problem. The Type 3 addressed many of the problems of the Type 94 and could give a much quicker solution while using radar ranges. However, it was never put into service. Destroyers and light cruisers used simpler (lighter and cheaper) systems such as the Type 2 for both HA and LA fire. However, that was not very effective as a HA system. Once more a new Type 5 system had been designed by 1945 with blindfire capacity but again it was not actually used. Meanwhile 25 mm guns on large ships and all guns on ships smaller than large destroyers were at best provided with the Type 95 or the related Type 4 fire control but the American report notes “It is curious that the Japanese Navy took no steps at all to design any other form of sight based on more advanced principles...” 

Now to my devious plans. I intend to announce that the IJN will help to fund a program to deliver a television to every village before the celebration of 2600 years of the Empire Imperial Japan at Its Zenith: The Wartime Celebration of the Empireâ€™s 2 ... - Kenneth J. Ruoff - Google Books and the Olympic Games in 1940. I also intend to fund the development of hearing aids to assist the naval gunners who often suffer hearing problems in later life. It has not escaped my notice that the British television industry was crucial in preparing Britain for large scale production of radar equipment after 1939 and that the success of America in producing proximity fuses that could be fired from a gun may have been greatly assisted by the development of a miniature value for hearing aids.


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## parsifal (Dec 10, 2014)

> I don't think that you have realized how stupid the IJN was with its codes. There is the issue of poor training. The additive tables of JN25B had 50,000 groups of numbers but 60% of the messages used the first 10,000 numbers as most clerks started on page 1 and as you mention they did not change the books often enough.



There is not much that is on par about IJN cipher security, but in practical terms how much worse were they? In the "This day In Europe" thread, ive been reading the DKM daily reports. By that time the B Dienst and other intelligence services were reading roughly 90% of RN and approximately 80% of the French Navy's "secure" signal traffic. These were being translated into uncannily accurate situation reports. not sure about DKMs intelligence on the USN and its merchant marines, but the few entries that do get entered in to the German Admiralty daily reports show remarkable details The effective difference between the Japanese and most of the allied navies in terms of their signal security was very minor.

What the Japanese were not prepreed for was the concerted effort the US put into breaking the codes, AND THEN PROCESSING THAT INFORMATION INTO SITUATION REPORTS OF DIRECT OPERATIONAL BENEFIT. neither were the Germans or Italians. The authors you are relying on are largely sensationalist in this regard, but in the end, Japanese SIGINT was overwhelmed rather than flawed in the first place. Not much they could do about that. 



> There is no sensible justification for having each code group divisible by three. If a transmission or decoding produced an error, there was only a one third chance that the erroneous group would be divisible by three. However, if the group cannot be found in the code book, it is clearly an error, and even with the divisibility by three, it is still not at all simple to guess what the correct group should be as any of the five numbers could be wrong. Clearly the IJN was reaching towards error checking codes but they were nowhere near getting that idea to work. They were, however, making their opponent's task much simpler. For example, occasionally the clerk would forget to add the superencipherment. Such signals were immediately identifiable as all the groups were divisible by three. The more mathematical consequences are explained in “The Flaw in the JN-25 Series of Ciphers, II” by Peter Donovan http://carma.newcastle.edu.au/jon/Preprints/Papers/Submitted Papers/Walks/Dirks notes/09duc1.pdf.



I did not know the details, but the results are pretty well known. Despite 10 years of effort, the USN had not had much success in deriving useful information from their reading of signal traffic. The qualities of the Yamato for example, were not known. The relative blindness was changed by two connected events. The first was the massive expansion in their SIGINT services, most notably in the analyst and interpretative areas. The intell just wasn't filed and forgotten anymore. Increasingly SIGINT was looked at, assessed and acted on. The second event, for the initial codebreaking effort was the enormous signal traffic generated by the April raids. how they did it is irrelevant. Until that US effort that swamped Japanese security, Japanise security was okay...not outstanding, poor in some respects. Once broken, the Japanese could not re-establish security nearly quickly enough. As the war progressed it became easier and easier to crack new codes. There was nothing the Japanese could have done about that.



> As we both agree, there was no way a simple superenciphered code such as JN-25 could have resisted the sort of effort used against it (and the slightly better RN codes also fell to the Germans). However, I believe that using conversion squares plus a grille with enciphered indicators would have resisted solution during WW2 with the same frequency of replacement of code books as OTL.



It took three years for the RN to make a major dent on German SIGINT, what the German effort lacked were the resources to use that mountain of information they uncovered. allied security was little better than the Japanese....that needs to be remembered in this discussion. I don't know about the USN, but I would be very surpised that it was much better than the RN.


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## cherry blossom (Dec 11, 2014)

parsifal said:


> ...snip...
> It took three years for the RN to make a major dent on German SIGINT, what the German effort lacked were the resources to use that mountain of information they uncovered. allied security was little better than the Japanese....that needs to be remembered in this discussion. I don't know about the USN, but I would be very surpised that it was much better than the RN.


The USN was better than the RN partly because they were richer and partly because they designed the most secure of the WW2 era cipher machines (although probably not the most reliable). Almost all major USN warships normally carried a ECM Mark II cipher machine which was completely secure during WW2 USS Pampanito - ECM Mark II. The USN was sufficiently worried about the possibility of an enemy capturing the ECM Mark II that submarines sent into shallow waters only carried less secure ciphers such as strip ciphers, CSP-642, and Hagelin derived machines. As even the capture of an ECM Mark II would not have imperilled USN codes, we can easily imagine how the choice to use a less secure cipher might have turned out badly. In fact CSP-642 turned out to survive IJN attacks and the USN may have calculated that they would see evidence in IJN signals if CSP-642 were to be broken. However, the USN may still have lost something as they may not have been able to send Ultra derived information to submarines using only the strip cipher.

We can go a little deeper into the security of strip ciphers. The strip cipher system used by the US State Department was broken or stolen by the Japanese Army, who naturally did not tell the Navy but did send details to Germany Christos military and intelligence corner: Cryptologic cooperation between Germany and Japan - The State Department's Strip cipher. The German analysis of the State Department system with new strips Christos military and intelligence corner: Compromise of the State Department’s strip cipher in 1944 and Bauer's Decrypted Secrets, pages 248-50, give clues on how such ciphers could be attacked without too much aid from captures although Rohrbach's paywalled article presumably gives the details An Error Occurred Setting Your User Cookie. According to Bauer, the German attack did require “massive use of Hollerith punch card machines and of special equipment ...”. For its attack on CSP-642, the IJN similarly used “IBM tabulators of the First Life and the Meiji Life Insurance companies” according to Kahn's Codebreakers, page 582, generally successfully determining the number of strips in use. However, little further progress was made and Kahn seems critical of the competence of the IJN codebreakers.

The Royal Navy had a relatively small but slowly increasing number of TypeX Machines Christos military and intelligence corner: The British Typex cipher machine for its most secure messages. TypeX was not broken during WW2 although it was not as secure as the USN's ECM II but could not be produced quickly enough to equip more than the important shore bases and major warships over most of WW2. Thus unlike the Americans and the Germans but like Japan, the RN used superenciphered codes rather than cipher machines for most messages and the RN codes were broken even pre-war by Germany. After RN codes were changed in August 1940 there was a see saw struggle until 1943 as B-Dienst continued to break into the new RN codes after they had been used for some time. It was only from late 1943 that RN codes improved to become secure after Enigma messages revealed the extent of German success against the earlier codes. The BAMS (Broadcast to Allied Merchant Shipping) code was also broken by both Germany and Japan after the capture of a codebook by the raider Atlantis.
ps. There is a good summary of British code security failures at http://chris-intel-corner.blogspot.gr/2014/02/british-cryptologic-security-failures.html


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## N4521U (Dec 11, 2014)

Switched sides!


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## cherry blossom (Dec 12, 2014)

N4521U said:


> Switched sides!


That is certainly a good idea, especially by 1941. However, one thing which doesn't change whichever side of WW2 the IJN ends up fighting on, is that they are going to need better anti-submarine warfare equipment and skills. 

There were voices in the IJN advocating more effort on ASW. Niimi Masaichi was one such officer
https://books.google.co.uk/books?id...v=onepage&q=Niimi, Masaichi submarine&f=false. Niimi became a Vice-Admiral but does not seem to have been very influential. Kaigun goes on to mention Oi Atsushi as a younger officer with similar concerns. Another voice was Sato Ichiro, who was with Niimi in the 36th Class at Etajima and like him became a Vice-Admiral. In 1927, he showed that he understood Japan's vulnerability https://books.google.co.uk/books?id...ge&q=sato ichiro brassey naval annual&f=false. However, Sato also lacked influence and had retired before the Pacific War. There is a revealing analysis of his views at 
https://books.google.co.uk/books?id...VP7VBcHvUqCigtAL&redir_esc=y#v=onepage&q=sato ichiro brassey naval annual&f=false. 

The IJN's best sonar at the start of the Pacific War was the Type 93 Mod 3 The Pacific War Online Encyclopedia: Type 3 Model 1 Sonar but the older Type 93 Mod 1 introduced in 1933 was the equipment in general use. After the war had started, Germany gave the IJN details of its S-Gerät (drawings were carried on the I-30 which was sunk but the drawings were salvaged) and this was the basis of Type 3 The Pacific War Online Encyclopedia: Type 3 Model 1 Sonar produced from 1944. Clearly, the German sonar was superior to the Type 93 Mod 3 but it is not obvious how it compared with contemporary allied equipment. The S-Gerät had first been tested on German destroyers in 1938 and it is clearly highly desirable for the IJN to buy or steal plans of either the German or a British system around 1938. 

The other issue is that the IJN needs to produce cheap but effective ASW vessels. The Tachibana Class http://en.wikipedia.org/wiki/Japanese_destroyer_Tachibana_(1944) and Ukuru Class http://www.combinedfleet.com/Ukuru_c.htm may have offered the best compromise of designs which saw production.


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## parsifal (Dec 16, 2014)

Japanese SONAR was actually fairly efficient, as the attached USN Post War report suggests. it included elements of the latest (1941) technologies taken from captured british ships, as well as some German technologies and some of their own making

http://www.fischer-tropsch.org/prim...Reports/USNTMJ-200B-0343-0412 Report E-10.pdf

The problems with Japanese ASW was not so much their detection gear, though it could have been better. They lacked an effective ahead throwing AS weapon other than a fairly ineffective mortar adapted from an army ordinance. Training for ASW was more or less non-existent 

The biggest problems with the Japanese ASW efforts were largely organizational and doctrinal. They failed to institute convoying until the middle of 1943, and did not have a dedicated Escort Command along the lines of the British Atlantic effort until September 1943. Even then, draftees into the command tended to be rejects from the surface navy in terms of personnel. Contrary to the popular myth, there was not really a shortage of escorts later in the war, roughly 700 vessels were built or converted for the purpose though the efficiency of many units was highly questionable. In terms of tactics, the Japanese failed to form proper hunter killer groups, or even retain the escorts in task groups so that they could develop effective team skills. Japanese escorts tended to blunder around the ocean depth charging indiscriminately with no object of corralling a contact into a planned AS trap. Sweeps tended to be of too short duration and not prosecuted with sufficient determination to be effective. Somewhere I very vaguley recall some sort of problem with the depth setting mechanisms of the DCs...... 

These weaknesses all tie in to the fact that convoy escort and ASW work did not fit into the IJN concepts of the decisive battle. A convoy battle meant a long war, and a long war meant Japan was going to lose. Certainly they could have done better, but its unrealistic to expect them to pour more resources into ASW in the pre-war build up when this was the sort of war they absolutely wanted to avoid.


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## Garyt (Jun 5, 2015)

Late addition here, but what about a DE class that uses coal based engines? High speed is not a priority, a DE that runs at 20 knots is acceptable. This would help with the fuel issues 2 fold, both reduces consumption with the DE's and perhaps putting more of them at sea.

For that matter, what about having some CVE's with the same method of propulsion? Again, high speed is not a priority.

Even mixed propulsion of coal/oil could work if the coal based is too inefficient, though personally I think coal based DE's would work fine.

This idea reminds me a bit of Ben Franklin's idea to arm the colonies army with longbows and crossbows as opposed to muskets


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## Shortround6 (Jun 7, 2015)

Coal fired boilers using turbines don't have a big speed loss. You do need a bigger boiler room. 

Reciprocating steam engines are where the speed loss comes from.


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## Garyt (Jun 12, 2015)

> Coal fired boilers using turbines don't have a big speed loss. You do need a bigger boiler room.



That's my point really. If they are designed as other escort vessels with the same amount of engine space, they will be slower.

But it would still seem to make sense I would think, for the oil starved Japanese Navy


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## VBF-13 (Jun 13, 2015)

Just my opinion, they spread themselves out too thin. They should have concentrated everything they had at Pearl, get us off of there. Then go get the rest.


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## parsifal (Jun 13, 2015)

There wasnt a lot left to throw into Pearl really. It took the IJN roughly 18 months to train carrier qualified pilots, and the training establishment was a huge nut to crack if they wanted to change that. I forget the precise figures but Ive seen a memo from Yammomoto dated the end of April '42, complaining already about the shortages of pilots they were suffering. They were receiving something like 150 carrier qualified pilots per year from memory in 1940, and that was the yhear to look at for Japan in 1942. For the Americans it was a whole different ballgame. They had far better resources in their training programs, and dint view pilots as an expendable resource like the Japanese. For the USN, the pilots being trained in the latter half of 1941 are the ones that were manning their carriers 1942-3. They were a little under done in early'42, but US pilots learnt real quick, and the fact they were receiving pilots in the thousands compared to the Japanese few hundred made all the difference. 

What the japanese threw at the Pacific fleet in December was about as much as they could muster. From there it was all downhill. By Midway, the big carriers were carrying approximately 15% less a/c than they had at Pearl, by the time of Eastern Solomons there was a partial recovery (because aircrew saved from the sunken carriers, but these too had been thrown on the fire. Thereafter replacement rates improved dramatically, but at the expense of quality. Aircrew in December 1941 had around 850 hrs of combat flying under their belts on top of around 500 hrs training time. Most of the air leaders had been flying since 1935-6. By the time of Phil Sea, there was virtually no combat time, and between 50-150 hrs of training hours. In that time, US pilot training had increased from around 250 training hrs to around 400 hrs, and combat times to an average of around 500hrs, up from nothing in 1941.

The pilots and machines manning the second line carriers in December 1941, the Zuiho, Hosho, Taiyo, Ryujo had already been combed out several times to build up the CAGs for the fast carriers. They lacked equipment, numbers, and skill to make much difference.

When I play sims of this scenario, as the Japanese, I actually hold back two of the fleet carriers and group them with the light carriers. I also dont comb out the CAGs of these smaller carriers. The four remaining fleet cariers that hit Pearl do a lot less damage, I dont even bother with a second strike over Pearl. I hit, then I run towards Midway. The two remaining fleet carriers plus the light carriers are escorting the Wake invasion forces to Midway, and the Guam invasion forces to Wake. Hitting midway early forces the USN into an unwinnable fight. They absolutely cannot allow the Japanese control of Midway that early, they have to implement some form of their plan Orange, and because the IJN carriers are concentrated, they usually destroy the USN fleet at sea more or less entirely. Game over from that point, provided the opponent silly enough to try and retake Midway. If they dont, there is a major security breach for Pearl, which is penalty enough in itself, but the Japanese move to isolate it from the rest of the TO by further occupations, Ellice, Gilberts, Johnston and Palmyra generally work to contain the major US supply and repair node very well. Keep a good part of your fleet at readiness at Kwaj, say 5 carriers, the rest at Truk on a training mission, building up spare CAGs as fast possible. Its admittedly unrealistic, but it at least points to some possibilities to an "alternative history".


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## VBF-13 (Jun 14, 2015)

What they brought to Pearl wasn't everything they had. Everything they had was spread out all over. I'm talking about surprising Pearl with everything they had, right on the jaw, but they didn't see it that way. Six months later was even almost too late for them. Had they been serious about taking the Hawaiian Islands, they'd have made it really tough. But instead that was just a hit and run to buy them some slack while they did their thing elsewhere. Had that not been viewed as an adjunct but as the main event and they'd have fortified it, they're five days away from the West Coast, and they cut us off from everything beyond the Islands, too. I just don't think they grasped the strategic importance of it. The Navy was doing the Army's bidding, there, really, for the most part, that's all that sneak attack was.


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## parsifal (Jun 14, 2015)

Your thinking along the lines of a direct attack into Pearl. The army was never going to commit to the minimum 45000 assault troops they thought they might need for that, whilst the Navy thought it closer to 90000. To support a force projection of that magnitude, they needed to use every ton of shipping at their disposal then some. Post war studies suggest the navy was closer to the mark incidentally. 

Direct invasion, if thats what you are angling for was a non-starter. The biggest operation the Japanese ever attempted, was in 1938 off Shanghai (or Hankow) I think, with about 25000 committed, and a couple of days sailing time from the Home islands. The japanese knew their limitations (well, sort of), and a direct assault was never within their capabilities. most competent post war studies Ive ever seen confirm that. That applies at any time, including just after the attack on Pearl. You do not attack a stronger opponent directly into the areas where he is most concentrated. that has about as much imagination, and about as much chance of success as one of Haigs "big pushes" on the Somme. 

The only other option I can think of that you might be hinting at is some sort of comb out of the land based air (LBA) assets. Wasnt going to happen, more importantly couldnt happen unless the Japanese were prepared to abandon both China and Manchukuo, and risk economic ruin within 3 months of their DoW. Quite apart from that, there just wasnt the training assets available to even contemplate such a conversion. I can only repeat, the assets they have with respect to carrier capable air power was Japan actually punching above its weight, not falling short.

The problem with the attack at Pearl was that there was no follow up, nothing to force the US fleet into battle prematurely. by the time the Japanese had realized what they needed to do, it was far too late for them. A Midway option in December 1941, or a similar location as Midway, would force the Americans to play ball when they couldnt. Sink the 1941 US Pacific Fleet as the Japanese and you really do win your war. I agree with Yammamoto however, in the long term, Japan could not defeat the US, therefore they should not fight the US. Any amount of victory in 1941 and 1942 is not going to change the long term outcome. From that perspective, Pearl Harbour was national Seppuku. 

.


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## VBF-13 (Jun 14, 2015)

parsifal said:


> Your thinking along the lines of a direct attack into Pearl. The army was never going to commit to the minimum 45000 assault troops they thought they might need for that, whilst the Navy thought it closer to 90000. To support a force projection of that magnitude, they needed to use every ton of shipping at their disposal then some. Post war studies suggest the navy was closer to the mark incidentally.
> 
> Direct invasion, if thats what you are angling for was a non-starter. The biggest operation the Japanese ever attempted, was in 1938 off Shanghai (or Hankow) I think, with about 25000 committed, and a couple of days sailing time from the Home islands. The japanese knew their limitations (well, sort of), and a direct assault was never within their capabilities. most competent post war studies Ive ever seen confirm that. That applies at any time, including just after the attack on Pearl. You do not attack a stronger opponent directly into the areas where he is most concentrated. that has about as much imagination, and about as much chance of success as one of Haigs "big pushes" on the Somme.
> 
> ...


The Midway force brought in a landing force. That was at a time when they thought they had the drop on us, as well. The Hawaiian Islands would have been greater in magnitude, obviously. It would have required an unprecedented commitment in resources, there's no question about that, just look at the troop estimates you supplied. Still, they had surprise on us. The branches weren't on the same page for it. Had they thought on an invasion, considered it, it wasn't much. They needed a commitment for that. That's the first thing they were lacking. They should have taken it, just as they took the Philippines. They could have, IMO, had they concentrated everything there. Instead, they kicked it, and had their fingers crossed we'd capitulate, but, instead, we mobilized. Six months go by, they try to get us, again, at least attract our big carriers, and get them out of the way. It's dragging on. They hadn't planned on it. After Midway, at least, they probably had a different plan on the books, every month. They're fighting a battle of attrition. And we're in a full-employment cycle, and throwing more at them than they can handle. Ah, hindsight...


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## Shortround6 (Jun 16, 2015)

VBF-13 said:


> They should have taken it, just as they took the Philippines. They could have, IMO, had they concentrated everything there. Instead, they kicked it, and had their fingers crossed we'd capitulate, but, instead, we mobilized. Six months go by, they try to get us, again, at least attract our big carriers, and get them out of the way. It's dragging on. They hadn't planned on it.



The problem for the Japanese is that it is a _major_ gamble because they cannot invade Hawaii and the Philippines at the same time. Assuming they are successful in Hawaii it is going to be 2-4 months before they can invade the Philippines and the _real goal_, the Dutch East Indies oil fields. The Japanese have a very limited amount of oil until they can get the oil fields under their control. Giving the defenders in the South East Asia 2-4 more months to dig in/prepare won't make them invulnerable but it would allow them to make a better showing than they did. Delaying the capture of the oil fields even more. They are in a race against time not only against the US getting it's production up and rolling but in getting the oil fields under control _and producing_ before their fleet just runs out of fuel in mid ocean,so to speak.


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## VBF-13 (Jun 20, 2015)

Shortround6 said:


> The problem for the Japanese is that it is a _major_ gamble because they cannot invade Hawaii and the Philippines at the same time. Assuming they are successful in Hawaii it is going to be 2-4 months before they can invade the Philippines and the _real goal_, the Dutch East Indies oil fields. The Japanese have a very limited amount of oil until they can get the oil fields under their control. Giving the defenders in the South East Asia 2-4 more months to dig in/prepare won't make them invulnerable but it would allow them to make a better showing than they did. Delaying the capture of the oil fields even more. They are in a race against time not only against the US getting it's production up and rolling but in getting the oil fields under control _and producing_ before their fleet just runs out of fuel in mid ocean,so to speak.


That's right. Throw in the rubber plants, too. The raw materials were the main event. The Japanese swept through that region because of the element of surprise, principally. Could they have done both, and got Hawaii, too? I'll concede, it would have taken more than they threw at MacArthur.


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## cherry blossom (Jun 20, 2015)

VBF-13 said:


> That's right. Throw in the rubber plants, too. The raw materials were the main event. The Japanese swept through that region because of the element of surprise, principally. Could they have done both, and got Hawaii, too? I'll concede, it would have taken more than they threw at MacArthur.



Don't give too easily!

As far as sane sensible military leaders were concerned, Hawaii was beyond Japan's reach. 

However, if we want innovative alternate history, we might turn to Glen239's famous Operation Tinkerbell, which we can find for example at The invasion of Oahu, December 1941. - Axis History Forum and Operation Tinkerbell preliminary: calculating shipping costs in Battleship Vs Battleship Forum. 

One of Glen's insights was that December 1941 was special in that most of the Japanese merchant fleet was idle and thus available to transport troops and supplies. Now clearly, the attack on Malaya and the Netherlands East Indies could not be delayed as the capture of the oil fields was critical. However, it was only necessary to prevent American forces on the Philippines from attacking Japanese ships, which could be done by bombing as occurred historically. The actual invasion of the Philippines could be delayed for months. Similarly, there was no urgency in attacking Guam or the British held Gilberts. 

Another surprising observation was that there were essentially undefended airfields on several islands in the Hawaii Chain, with only Oahu having a significant garrison (note that the Japanese leaders probably never imagined that such airfields would be undefended). Thus Glen came up with the idea of Japanese troops landing on the other islands shortly after the Pearl Harbor attack and establishing bases. As the Japanese Fleet would have to stay around, it would probably encounter any USN ships that were at sea and that remained in the vicinity; in particular Enterprise and Lexington. Thus it is quite plausible that Japan can create a situation in which the control of the waters around Oahu and the air above are contested on fairly equal terms. As both fleets will depend on bases two thousand miles away, control may swing back and forth. However, the IJN was at its strongest relative to the USN just after Pearl, so the IJN may control the sea most of the time.

Could the IJN achieve anything else. Well they could bombard Oahu and sink any surviving ships in Pearl. Surely not! What about the coastal artillery? Well once again we find that America was not quite ready for war. The guns were all in the open and could be disabled by the Kido Butai's dive bombers. 

But could Japan take Oahu? Well that is the hard question. The IJA would certainly find it hard to establish itself on Oahu. The IJA and SNLFs did make successful landings against some opposition, for example, at Kota Bharu in December 1941 or on Hainan Island in February 1939. However, they did not have the training and techniques of 1944-5 US Marines. The biggest difference may have been that IJN ships had not practised supporting landings and there was no radio communication from the shore to call for gunfire support. Off Hainan, instead of directly supporting, the IJN bombarded communications according to a rigid plan during the night landing. Clearly a night landing, perhaps further screened by smoke, would make getting ashore through the Hawaiian surf even more exciting. At Shanghai, the IJN was willing to bring its ships close to the shore when Japanese infantry were pinned down. However, the problem off Oahu is that there may be many other things for IJN ships to do. OTL Japanese amphibious tank development Type 2 Ka-Mi - Wikipedia, the free encyclopedia was also running too slowly to assist unless we add a POD that planning begins well before late 1941. Thus a landing may well fail. However, if some Japanese forces are established ashore and can be supplied, it seems likely that the US forces will be worn down as they cannot be easily resupplied.


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## parsifal (Jun 21, 2015)

capture of oahu was a high stakes gamble, with low returns likely. The prize to go for was the US Pacific Fleet. Entice or force it into battle before it is ready, and you win perhaps 2 years of respite from US attentions. Time enough to prepare a welcoming committee for the advancing Americans as they come storming back across the Pacific. A one sided easy victory in 1941 or early 1942 will deliver all that an invasion might without near the risk. 


It might be possible, if the IJN is not put on the rack by late 42 as it was historically, to have an IJN 50% stronger than it was historically, and the USN 40% weaker than it was historically in June 1944. Imagine a Phil Sea with all 6 of the big carriers, plus 2 x Taihos, a couple of Unryus, an extra Yamato class, the 2 BCs, versus the US fleet less the prewar navy. If the aircrews are more closely matched quality wise, Phil Sea becomes almost unwinnable for the USN, at least in the 1941-5 time frame.


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