Rn vs IJN

[Greg Boeser]

I suppose your peg-leg is a result of taking an arrow to the knee?

Avast, nay! Ya lubber. Lost that tradin' broadsides with a French frigate off Bermuda. Round shot took it clean off at the knee.

 

[Shortround6]

The Japanese may well have not shot well at long ranges.
Very few (any?) nations 8in guns shot well at long range. Long range is relative and long range for an 8in gun is actually medium range for battleship guns.
Unfortunately this was NOT recognized in the late 20s/early 30s when most of the 8in guns and ships were designed/built.
40 degree or so of elevation, tall masts with spotting positions at the top, floatplanes to correct fall of shot.

Ability of 8in guns to fire out to around 30,000yds (depends on country/gun. etc)
also depends on sunny days, no haze, calm seas and blessings from the ballistics gods.

BUT, by god, nobody else was going to outrange US!!!
Turns out you needed really good shells, good guns NOT closely spaced, VERY good range finders and very good plotting and ballistics computers (analog).

A few points.
1, if you double the range the shells fall into an area of 4 times the area. So chances of hit is 1/4 at double the range.
2. #1 is for a stationary ship and a stationary target. a 30 knot ship moves at 50fps. for a British 8in gun (The Japanese tables don't give times of flight) the times of flight are 6.2 sec for 5,000yds, 24.7 sec for 15,000 yds and 78.6 sec for 29,000yds. So at 29,000yds the 30kt target ship will have moved 3,930 feet (6.7 ships lengths for the cruiser pictured) in the time it take for the shell to leave the muzzle and make it to 29,000yds. the gun can fire 3-4 shots before the first ones get there.
3. there is a crap load of other stuff you have to know, air temperature, temperature of the powder in the magazines, air pressure, humidity, gun wear, you might even have to take into account the rotation of the earth and orientation of the flight path (North/South or East/West).
Turns out that long range gunnery, even with radar, was something of a illusion. Without radar there were charts that showed probable errors in range from the range finders based on the distance and the length of the range finder. Now lets go back to the Pensacola pictured. The biggest/longest rangefinders are in the turrets which are close to the water and can't see over the horizon that well, then you have the rangefinder on top of the Bridge and there is a rangefinder in the penthouse on top of the mast. Problem here is that that mast top range finder moves around even in a calm sea. Each range finder has it's own advantages and disadvantages.
Practical 8in gun fire distance was a lot closer to 20,000yds and as we have seen, even the high teens was rather problematic. Down around 5,000 yds things get a lot simpler. Almost point and shoot Target is only going to move about 1/2 a ship length, point the gun about deck height and if you are 1000 yds off you either hit the superstructure or hit the hull.

Doing well in a close range gun fight does not mean you have good accuracy at even 2/3rds max range. Change in accuracy (group size/shell pattern) tends to go up with cube of the range and not the square I used as the first example.

 

[Thumpalumpacus]

Avast, nay! Ya lubber. Lost that tradin' broadsides with a French frigate off Bermuda. Round shot took it clean off at the knee.

Mmhmm ...

 

[Shortround6]

Mmhmm ...

Me thinks he has been getting into the grog supply

 

[WARSPITER]

I think you are doing a little bit a cherry picking here.

Actual engagement data is not cherry picking. For a navy with a doctrine to bring an enemy fleet into a medium to long
range gunnery fight after weakening it the IJN training and fire control showed a distinct lack of ability to carry out the
doctrinal aims.

Also, within this scenario things are less stressful in Europe so even if the RN can send half of the forces available in 1942
the IJN is outnumbered.

 

[Shortround6]

I will note that in the late 20s and early 30s the 4 or so large AA guns on BBs and Cruisers were to drive off the enemy spotting planes (spotting fall of shot for gunnery corrections, not actually finding the enemy ships although they could that) more than they were there to drive off strike aircraft.

It took a while for most navies to realize the that the number of days per year out of 365 days where the ships could actually see 30,000yds was rather small. Or perhaps I should say that some people knew it well, but nobody wanted to get caught out ranged on the few days that the weather was that good.
It did take bit longer to realize how much tonnage was going into the long range gun part of the ship.
The heavier, more complicated mounts were easy to see. The tons of weight very high up in the ship were harder to see. The plotting rooms and fire control equipment down under the armor deck is harder to see. The tonnage devoted to "spotting" planes is somewhat over looked.
Picture of a WW I plotting table.

The paper rollers changed speed according to estimates of ships own speed and the estimated speed of the target. Pens drew the tracks of the ships on the paper with inputs from the range finders and bearings. The ONLY way to guess at where an enemy ship would be in the future (30-70 seconds) was to track it's movements in the past and you needed to plot a number of ranges and bearings to get an accurate track.
Information from these primitive "computers" would be sent back up to the gun directors or coordinated with them to offset the guns the needed amount in train and elevation to get the shells to land in the predicted area of the ocean the target was expected to be in.

 

[EwenS]

The Admiralty Fire Control Table Mk.VI installed in HMS Belfast (completed 1939). Progress!

 

[Peter Gunn]

Even the Japanese admiral in charge says that things could have gone much differently.

"The element of surprise worked to our advantage and enabled us to destroy every target taken under fire. I was greatly impressed, however, by the courageous action of the northern group of U. S. cruisers. They fought back heroically despite heavy damage sustained before they were ready for battle. Had they had even a few minutes' warning of our approach, the results of the action would have been quite different.

Which does a couple of things for me:

What if Crutchley <sp?> and Australia hadn't been called away, with an experienced RN Adm. in command, would that have made a difference? Would the northern force been alerted then and ready. Admittedly command of the northern force seems lacking but if they were appraised of the situation what then?

OK, historically, with Australia out of the picture if Capt Bode of Chicago had informed Riefkol <sp?> perhaps again, the northern force is ready, however, with the lackluster command of the USN at that point maybe it wouldn't have mattered.

Admiral Scott was aboard I think San Juan or Atlanta in the eastern force and even he thought the northern and southern forces were shooting at each other.

But to the discussion of RN v. IJN, I dunno, at night, in The Slot, I might still give the nod to the IJN in a night surface battle, but only just.

 

[Shortround6]

Thank you.

Please note all the dials/knobs/cranks that required several operators.
In less than 30 years they were on the 6th MK of fire control table?
Granted a few other navies came in a little late a skipped the 1st or 2nd versions but in 1939 not all RN ships had the latest Mark (?) and not all other navies had exactly the same fire control tables. In the late 30s the Soviets were buying Italian fire control equipment.
A lot of navies had trouble with long range accuracy. The US de-rated a number of their large guns (dropped velocity by 100fps or more) in order to get better accuracy at long range for instance. from USA 8"/55 (20.3 cm) Marks 9, 10, 11, 13 and 14 - NavWeaps

" As commissioned, the early cruisers had poor dispersion patterns, sometimes as large as 2,000 yards (1,830 m) for a full salvo. Some of these problems were due to the guns having a very high muzzle velocity and poor shot seating. Extensive testing to determine the cause of the problems was performed in 1933 at Manila Bay with the assistance of the Coast Artillery and the results sent to BuOrd. Corrections included reducing the muzzle velocity and relining the barrels."

Now this is ballistics and NOT fire control/range finding.
Also shows a pet peeve of mine. Telling me how big the dispersion pattern is without giving the range actually says very little.


The Japanese were setting up their navy for the big decisive one/two day blue water battle. They knew they could not beat the US navy in a daylight battle. it was not that the US was that good, it was that the US was that big. According to battle planning using Lanchester's square law the power of a force is equal to the square of it's numbers, so with the Japanese having a force ratio of 3 to 5 vs the US they were actually dealing with a ratio of 9 to 25 if everything was equal. The Japanese planned for many years to equalize, as much as possible, the numbers in the daylight gunnery battle by attrition during a preceding night battle using torpedoes. This was carefully choreographed with destroyer divisions/squadrons being lead by light cruisers punching their way through the US screening forces (destroyers & light cruisers) with the support of heavy cruisers to get the Japanese destroyers within torpedo range (with reloaded tubes) of the US battle fleet and hopefully sink or cripple (slow down) enough US battleships so that the gun dual the following morning would be between near equal numbers.
Details varied over the years but this was basic plan from the 1920s on. Aircraft played a larger role later in the 30s and the capability of the torpedoes improved greatly. But the Japanese plan/s always called for superior night fighting capability/training over numbers (banned by treaty) or technical superiority (which might change and then change back in a few years).
The Japanese cheated/lied in regards to the size/tonnage of their ships but they could not fit everything they wanted into the ships. Their ships were built with this basic goal in mind and some secondary roles were given low priority. The Japanese did not what to fall too far behind in some aspects but there was only so much they could do or there was only so much they could fit on a ship. Torpedo reloads or high angle/AA gun directors? High speed or fire control equipment high up for good vision (top weight). Other navies made other choices that made sense to them.

 

[EwenS]

Thank you.

Please note all the dials/knobs/cranks that required several operators.
In less than 30 years they were on the 6th MK of fire control table?

No many more than 6!!!

There were a number of series of fire control tables in the RN.

WW1
There were the Dreyer Fire Control Tables in various marks fitted 1911-1922 to the big ships

Dreyer Fire Control Table - The Dreadnought Project

dreadnoughtproject.org

Interwar
Saw the development of the Admiralty Fire Control Table for large ships of which there were 10 marks.

1. Mk.I went into the Nelrods completed in 1927. Contained 21 modular units mounted on 2 pedestals in 2 separate compartments all connected by mechanical shafting.
2. Mk.II went into 7 Kent class cruisers
3. Mk.III went into remaining Counties, York & Exeter
4. Mk.IV Leander
5. Mk.IV* Orion, Achilles & Neptune
6. MK.V Ajax, modified Leanders, Arethusa class, Southampton & Newcastle
7. Mk.VI Town class cruisers except Southampton & Newcastle
8. Mk.VII Warspite, Valiant, QE & Renown
9. ?
10. Mk.IX KGV class
11. Mk.X Vanguard

The differences between systems were numerous, with some representing simplifications of what went before. There was an article in Warship 2002-03 for anyone who wishes to pursue it further.

Destroyers were fitted with a simplified version, the Admiralty Fire Control Clock (AFCC), the handbook for which is here:-

B.R. 901/43, Handbook of The Admiralty Fire Control Clock

 

[z42]

Very few (any?) nations 8in guns shot well at long range. Long range is relative and long range for an 8in gun is actually medium range for battleship guns.
Unfortunately this was NOT recognized in the late 20s/early 30s when most of the 8in guns and ships were designed/built.

What would be the smallest gun then that, from a long range accuracy perspective, would not be disadvantaged compared to a 'proper' battleship gun?

The German 28 cm might be a contender, given the 24+km hit on Glorious. Though one cannot discount the effect of pure luck in that either..

For a British 8in gun (The Japanese tables don't give times of flight) the times of flight are 6.2 sec for 5,000yds, 24.7 sec for 15,000 yds and 78.6 sec for 29,000yds.

Annoyingly, navweaps doesn't list flight times for the German 28cm guns. But for comparison, the UK 15" has a flight time of 57.3s to 30kyds. So more difficult for the 8", the 15" shaves a 1/3 of the flight time. But not totally impossible either.

 

[Shortround6]

What if Crutchley <sp?> and Australia hadn't been called away, with an experienced RN Adm. in command, would that have made a difference? Would the northern force been alerted then and ready. Admittedly command of the northern force seems lacking but if they were appraised of the situation what then?

OK, historically, with Australia out of the picture if Capt Bode of Chicago had informed Riefkol <sp?> perhaps again, the northern force is ready, however, with the lackluster command of the USN at that point maybe it wouldn't have mattered.

Well, you don't throw flammables overboard on 5-10 minutes. You can get guns pointed in the general direction you think trouble is coming from. It takes about 25 seconds to swing the 8in turrets 90 degrees and those 8in guns (or the Japanese) can fire 3-4 rounds per second. Get star shells for the 5in guns? Change speed/direction? make things difficult for the enemies torpedo/fire control?

Admiral Scott was aboard I think San Juan or Atlanta in the eastern force and even he thought the northern and southern forces were shooting at each other.

I just have one account of the Hobart tracking the Japanese but they probably didn't know they were the Japanese until it was too late.
The Allies had 4 or 5 groups of ships in area that night not counting the two picket destroyers in the west. The two transport groups get short shrift but the eastern warship group had two groups of transports between them and the battle/s. The US failed both to pick up the Japanese on radar multiple times but either failed to notify command or misidentified radar targets.

Unfortunately this lack of situational awareness (figuring out who was where) was still going on in Dec 1942 and basic command decisions were still being screwed up at the of Battle of Tassafaronga.
Rear Admiral Carleton H. Wright apparently didn't know how to execute a torpedo attack and didn't know the capabilities (ranges) of the US torpedoes.
Having an Admiral decide when and where to open fire is one thing, denying permission for captains open fire while your bridge officers explain that yes, the US destroyers are easily within torpedo range is another thing entirely. Followed by announcing the Japanese that they are under attack within 1-2 minutes of the torpedo launch maybe evasive action is called for? ruining the torpedo attack. Now maybe the Japanese would have spotted the US without them opening fire and managed to take evasive action anyway.

US Admiral had at least 3 own goals.
1, not knowing his own weapons capabilities and delayed firing torps until the range was opening and bad angle.
2, opened gun fire too soon,
3. failed to order speed/course corrections to throw off Japanese torpedo attack. Forget the Long Lance stuff, just assume that if the enemy ships are well within your range you are within their range. Wright had just been told that the US torpedoes had a range of over twice the distance that the US Destroyer Captains wanted to fire at (and they fired a bit longer).
Just assume that even if the Japanese torpedoes are not as good as the US torpedoes they are good enough to work at the distance separating the two lines of ships. Japanese executed a turn away, and then did a 180 degee turn to reverse direction but that turn was in the direction (closer) to the US forces.

 

[Shortround6]

What would be the smallest gun then that, from a long range accuracy perspective, would not be disadvantaged compared to a 'proper' battleship gun?

The German 28 cm might be a contender, given the 24+km hit on Glorious. Though one cannot discount the effect of pure luck in that either..



Annoyingly, navweaps doesn't list flight times for the German 28cm guns. But for comparison, the UK 15" has a flight time of 57.3s to 30kyds. So more difficult for the 8", the 15" shaves a 1/3 of the flight time. But not totally impossible either.

Deutschland in 1936

Note the wider range finders in the large triple turrets, the largish range finder on top of the bridge and the really large range finders on top of the mast and on the aft superstructure.

For long range high velocity helps, if it does not cause increase dispersion. Better shells can help a lot (better more streamline shape) although this sometimes has to be designed in from the start, or extensive refits. designing longer, more streamline shells can often require new shell hoists, magazine handling equipment and shell handling equipment in the turret/gun houses. Lets also remember that in the 30s smokeless powder (not black powder) was less than 50 years old and the whole long range thing was less than 20 years old.
Everybody was thrilled with 20,000 yd Battleship guns after 1916 and Jutland (many of those guns were either just short of 15,000 yds or just over. restricted elevation).

Before radar the real limit for practical gunnery was how far could you see. That roughly 30 meter high rangefinder on the Deutschland was good for about about 35km on really clear day.

 

[Wild_Bill_Kelso]

One thing about Savo Island, the Chicago had radar, but the captain was only turning it on intermittently every half an hour. The timing turned out to be bad vis a vis the arrival of the Japanese ships. The decision may have been a grave mistake given where they were, but it was USN policy at that time and there was a good reason for it. One which still exists today: a major Achilles heel of radar.

When you use the radar, you are yourself giving your position (and existence) away. It's a lot easier to detect radar emissions than it is to run your own radar set.

 

[Shortround6]

One thing about Savo Island, the Chicago had radar, but the captain was only turning it on intermittently every half an hour. The timing turned out to be bad vis a vis the arrival of the Japanese ships. The decision may have been a grave mistake given where they were, but it was USN policy at that time and there was a good reason for it. One which still exists today: a major Achilles heel of radar.

When you use the radar, you are yourself giving your position (and existence) away. It's a lot easier to detect radar emissions than it is to run your own radar set.

That may be true but it also seems to show a lack of understanding about radar in the USN.

The US had just invaded Guadalcanal, Tulagi, and Florida Island on the 7th. The Japanese knew where they were and they knew they weren't going anywhere.
The invasion fleet had been bombed on the 8th, kind of another clue that the Japanese knew where they were. Existence has been posted up on billboards.

Now the US carrier group may have wanted to keep their location secret but the transports weren't going anywhere and the escorts weren't going anywhere.
Keeping the Chicago a semi secret by only flashing the radar every 1/2 hour while having a pair of Destroyers patrolling each entrance with constant radar isn't keeping your location secret either.

Receiving the radar signals only gives direction. It does not give distance. It also doesn't tell what sent it (what kind of ship or even if it was a ship, unless land radar uses different frequency and if your opponent knows that at the time.

Having a mobile force (carrier group) go radio/radar silent while trying to move 100-200 miles at night makes some sort of sense.
Having a force in a fixed location (invasion transports 1/2 unloaded) try to hide by only turning on 1/2-1/3 of their radars is really using the ostrich defense. Stick head in the sand and hope attackers pass them by while other defenders shine their flashlights around.

 

[Shortround6]

repeating RCAFson's earlier post.

Radar in the RN:

As of 28 Sept 1941 (Howse, p.99-101) :

84 RN ships had at least one FC radar (284/285)
48 cruisers and larger ships has at least one type 79/279/280/281 AW radar
303 RN ships had AW/SW radar (Type 286/286P/290) and 40 had centimetric 27X series radars.

These numbers would have increased somewhat by 6 Dec 1941.

This is 10 months before Savo,
The RN a lot of time to work out radar problems near land masses and other problems. If they couldn't work out the problem they would have been aware of it and taken precautions. Like trying adjust patrol routes to minimize shore reflections or ghosting.

I would also point out that the Japanese had no (or 1?) active radar aboard ship and even almost a year later had fewer than 10.

At a quick count the British had 6-7 different naval radars by the end of 1940, by the end of 1941 they had 14-15 different radars and added 3 more (or upgraded version ) in 1942.
There were more in 1943 and they kept adding. Not all worked they way they wanted but the Japanese were 2 years behind or more. Better binoculars were not going to make up the difference.

 

[Wild_Bill_Kelso]

You sure hate those nice Japanese binoculars mate... I think you should come around, they are niiiiice

I noticed they got a lot of play in the new Godzilla film

 

[Glider]

You seem to be confused. There were 5 cruisers (2 heavy and 3 light) on the Allied side, plus 9 destroyers, vs 4 cruisers (2 heavy, 2 light) 14 destroyers and 10 transports on the IJN side.

The results were 2 CL sunk, 3 DD sunk, and 1 CA (Exeter) badly damaged and just about crippled. You may be thinking of the second battle in which she was finished off.



I'd say they did pretty well in this battle, compared to the Allied forces.

I have always been thinking of the 2nd Battle of the Java Sea when it was one against four and it was in that battle that the Japanese took an hour to hit her.

 

[Wild_Bill_Kelso]

I never once even came close to suggesting that the Japanese were not behind on radar. Obviously they were. I'm just highly dubious that:

A) Excellent naval optics don't matter
B) Radar alone can make the RN better than the IJN, and overcome superior Japanese torpedoes, aircraft, and ships.
C) and probably tactics too.

I'm also not suggesting that Savo Island wasn't a big blunder on the American side, I was simply pointing out that the IJN performed well, including in gunnery, and with my last remark, that radar was not a panacea. Sure you might only know direction, but you know one other thing - an enemy vessel is out there, and you know roughly how far away it is because radar doesn't travel forever across the ocean. It's probably within the horizon.

Between the use of seaplane scouts at night, such as they did use at Savo island, using seaplanes for marking targets with flares, used perfectly by the IJN in that battle, star shells (used by both sides in the battle) and the oft ridiculed superior naval optics of the Japanese, combined with the clearly very good training and discipline, and torpedoes with vastly more speed and range, I am just not sure radar alone is going to tip the scales, in say 1942 or 1943.

Except maybe in certain weather conditions.

I would like to read about some examples of the RN using radar guided gunnery in that period or before.

 

[Wild_Bill_Kelso]

I have always been thinking of the 2nd Battle of the Java Sea when it was one against four and it was in that battle that the Japanese took an hour to hit her.

Well you can't get to the second one without the first mate. Put them together it looks bad for the RN, (and Americans and Dutch) IMO.