Rn vs IJN

EwenS · Sep 3, 2023

Glider said:
I agree with a lot of the above but the only observation I have is that during the war I understand that the British 8in cruisers lost their torpedo's to give the weight to AA guns, directors and Radars.

Only partly true.

When the RN Kent class were modernised in the late 1930s they lost their TT. Given the requirement to remain within Treaty displacement limits choices had to be made about what was kept, removed or added. In this case the view was taken that, as these ships were then more likely to be operating on the shipping lanes not as part of the main fleet, aircraft facilities were more important than TT so the latter were removed and the former upgraded. That represented a change in the way the RN envisaged using these ships between their original design and the mid-1930s. Australia also lost hers at this time but Canberra retained hers until sunk.

The other County classes plus Exeter & York on the whole retained theirs. An exception was Sussex which did lose hers and X turret to gain more AA in a 1944/45 refit.

Generally the RN preferred to sacrifice gun power rather than torpedo power in its cruisers. So later classes, with only a couple of exceptions, retained their TT into the post WW2 period. RN cruiser designs in the 1944-47 period increased the TT armament to 4 quad mounts, but none of these were built.

Shortround6 · Sep 3, 2023

EwenS said:
In this case the view was taken that, as these ships were then more likely to be operating on the shipping lanes not as part of the main fleet, aircraft facilities were more important than TT so the latter were removed and the former upgraded. That represented a change in the way the RN envisaged using these ships between their original design and the mid-1930s.

Indeed the Threat/s operating in the shipping lanes changed. An 8in Cruiser might be the convoy flag ship or be operating in a hunter group looking for raiders. With carriers being few in numbers it fell to the large Cruisers to provide aerial recon, obviously this also changed with time.
The numbers and types of surface raiders also changed with time.
Ships doing actual convoy protection (in visual sight of the convoy?) might well want torpedoes (small cruisers & destroyers) as even a single torpedo hit is going to cause the raider to abort and head for home, regardless of the raiders size. Regardless a torpedo hit will buy time for the convoy to scatter if needed.
A single 8in cruiser can depend on several smaller ships to execute the torpedo attack and not have to "dual" the raider one on one in torpedo dual.

The mounting of torpedoes on the large cruisers covered a time period of around 13-14 years from first 8in cruisers to war in 1939 so there was time for several changes of mind.

Reluctant Poster · Sep 4, 2023

Thumpalumpacus said:
If you look at it through the lens of Kantai Kessen doctrine, their putting torpedoes makes sense.

So far as their tradeoffs of utility vs hazard, that the DDs got more hits strikes me as luck of the draw, rather than inherent advantage of ships themselves. But the Japanese had already decided to accept the hazards -- and those same hazards were present on the DDs. Neither the Japanese nor the Americans had any foreknowledge of how things would shake out, either in getting or taking hits.

In hindsight, you're indeed correct that the torpedoes didn't pull their own weight due to circumstances -- but that doesn't mean the Japanese CAs were not more powerful. It just means that the circumstances of war meant that those advantages weren't really leveraged. It's a subtle but distinct difference that is easily obscured by hindsight.

Your statement was that the torpedoes on the Japanese cruisers were the great equalizer. In the battles as actually fought they were not.
Destroyers get more hits because they can get closer to the target. They are considered to be expendable and the greater risks of oxygen fueled torpedoes makes more sense in that application.

Thumpalumpacus · Sep 5, 2023

Reluctant Poster said:
Your statement was that the torpedoes on the Japanese cruisers were the great equalizer. In the battles as actually fought they were not.

Yes, for reasons I've already spelled out.

Reluctant Poster said:
Destroyers get more hits because they can get closer to the target. They are considered to be expendable and the greater risks of oxygen fueled torpedoes makes more sense in that application.

Sure. But that doesn't address the cruisers. No shot is a sure thing. But I think arguing that IJN cruisers were inferior for having torpedoes that, by happenstance, missed, is -- again -- hindsightium. Had they hit, you would likely sing a different song.

Shortround6 · Sep 5, 2023

Because naval battles were relativity rare (compared to aircraft or tanks) it is sometimes a little difficult (or more than a little) to figure what the results of the next battle will be (or hypothetical) based on past performance.

For instance, depending on reports/sources, the very same WW II torpedo was either,
The most successful torpedo of the war (50% hits)
A fairly successful torpedo (33% hits)
A total failure...................(0% hits)

This is the British British 24.5in torpedo as carried by the Nelson and Rodney.
Reports/accounts claim either 2 or 3 fired with either 1 or 0 hits.

The sample number is just too small to do anything with.

The number of battleship shells fired (11in and up) vs the number of hits they got are well into the low single digits as are the numbers of 8in and 6 in shells fired by navies around the world. Now try to figure out the rather variable effects of even 1 or 2 hits on the overall battles once a hit was obtained. See the battle of Calabria which was "decided" by a single 15in shell hit on ship 611ft long. Or see Hood.

The Japanese were gambling from the start. They knew what the American building program was. They needed a way to equalize the superior numbers of the American Navy. Playing it safe with lower performance torpedoes (or no cruiser torpedoes) wasn't going to give them the victory they wanted.

WARSPITER · Sep 5, 2023

In one earlier engagement the IJN used the usual long range tactic of firing Type 93's from 22 to 24,000 yards. Five hits were attained
with losses and heavy damage to the USN force. The better night observation equipment and training together with the long range
Type 93 gave the IJN a distinct advantage even though it took 12 or more minutes for the torpedoes to get to a target group at those
ranges.

In a later engagement where the USN had SG1 radar and better fire control they were able to move to where they wanted to be while
keeping the IJN ships on scope. The SG1 allowed the USN ships to start firing before the IJN vessels knew they were there. This was
coupled with more changes of direction as the distance closed which made it a waste of time for the IJN ships to use torpedoes.
The IJN came off badly in this instance.

In the first scenario the IJN ships got the five hits by firing 76 torpedoes which is close to a 5.6% hit rate.
In the second scenario the USN hit rate was still less than 10% until the range closed.

Different tactics at different stages of the war with the IJN having the earlier advantage and losing it over time.

By 1943 allied ships and aircraft were sinking more Japanese ships as they knew the vulnerability of the oxygen/kero torpedo sections
on board. Some Japanese ships had already started to fire off torpedoes when attacked by air as they also knew what happened when the torpedo
sections of their own ships were hit.

It's all a matter of the time line and the technological changes along it.

Reluctant Poster · Sep 6, 2023

WARSPITER said:
In one earlier engagement the IJN used the usual long range tactic of firing Type 93's from 22 to 24,000 yards. Five hits were attained
with losses and heavy damage to the USN force. The better night observation equipment and training together with the long range
Type 93 gave the IJN a distinct advantage even though it took 12 or more minutes for the torpedoes to get to a target group at those
ranges.

What engagement was that?

WARSPITER · Sep 6, 2023

Battle of Tassafaronga near the end of 1942.

Thumpalumpacus · Sep 6, 2023

WARSPITER said:
Battle of Tassafaronga near the end of 1942.

... albeit fired from destroyers.

Reluctant Poster · Sep 7, 2023

Thumpalumpacus said:
... albeit fired from destroyers.

And not from 24000 yards . The range was within US torpedo range. Travel time was 4 minutes

WARSPITER · Sep 7, 2023

22 to 24000 yards was the doctrine and what the training had been for. Tassafaronga is probably not the one I was thinking of
but there were 40 or so fired at one stage. The US report after the battle supposed submarine activity as even at that stage
no one had realised the range of the type 93. It wasn't until 1943 that this was known and tactics developed to combat it.

Reluctant Poster · Sep 21, 2023

WARSPITER said:
22 to 24000 yards was the doctrine and what the training had been for. Tassafaronga is probably not the one I was thinking of
but there were 40 or so fired at one stage. The US report after the battle supposed submarine activity as even at that stage
no one had realised the range of the type 93. It wasn't until 1943 that this was known and tactics developed to combat it.

Japanese long range tactics were a fantasy which did not work all that well in the real world. The idea of launching torpedoes in the dark at 22000 meters is just plain silly when that is beyond visual range at night. That being said the USN tried it's best to fulfill Japanse fantasies by continuing to steam in straight lines even after they had suffered losses from torpedoes. Even if you believe the torpedoes came from submarines and not from surface vessels that doesn't excuse you from not zigzaging.

The most egregious example was the loss of the Northampton at Tassafaronga. It carried on in a straight line for 21 minutes after the first torpedo struck. Ludicrous. Regardless of what launched the torpedoes evasive action should have been taken. Honolulu did and was the only cruiser not hit.

Juha3 · Sep 21, 2023

WARSPITER said:
In one earlier engagement the IJN used the usual long range tactic of firing Type 93's from 22 to 24,000 yards. Five hits were attained
with losses and heavy damage to the USN force. The better night observation equipment and training together with the long range
Type 93 gave the IJN a distinct advantage even though it took 12 or more minutes for the torpedoes to get to a target group at those
ranges.

In a later engagement where the USN had SG1 radar and better fire control they were able to move to where they wanted to be while
keeping the IJN ships on scope. The SG1 allowed the USN ships to start firing before the IJN vessels knew they were there. This was
coupled with more changes of direction as the distance closed which made it a waste of time for the IJN ships to use torpedoes.
The IJN came off badly in this instance.

In the first scenario the IJN ships got the five hits by firing 76 torpedoes which is close to a 5.6% hit rate.
In the second scenario the USN hit rate was still less than 10% until the range closed.

Different tactics at different stages of the war with the IJN having the earlier advantage and losing it over time.

By 1943 allied ships and aircraft were sinking more Japanese ships as they knew the vulnerability of the oxygen/kero torpedo sections
on board. Some Japanese ships had already started to fire off torpedoes when attacked by air as they also knew what happened when the torpedo
sections of their own ships were hit.

It's all a matter of the time line and the technological changes along it.

You maybe are thinking about the Battle of the Java Sea on 27 February 1942 where during the night phase of the battle Dutch CLs Java and De Ruyter were torpedoed in the same devastating salvo laucnched by IJN CAs Nachi and Haguro from 14 000 yards. Nachi launched 8 and Haguro 4. Earlier during the afternoon Haguro had launched 8 torpedoes at 12½ miles and CL Naka and DDs altogether 31 torpedoes at distances between 13,000 and 15,000 yards. A Dutch DD was hit and sunk, probably by one of the torpedoes launched from the Haguro. Later Naka's DD Sqn 4 launched 24 torpedoes at a range of 21,000 yards, all missed. Later Nachi and Haguro launched more torpedoes from 19,000 yards and IJN CLs and DDs between 18,000 and 10,000 yards but two DDs which launched at 6,500 yards. During the evening CL Jintsu and its 8 DDs launched torpedoes at a range of slightly under 21,000 yards. Dull doesn't give the number of torpedoes launched during these attacks.

WARSPITER · Sep 21, 2023

Thanks, that is probably the one. It seems the IJN tactics held sway through most of 1942 and the USN
counter tactics proved to be superior from 1943 on.

SaparotRob · Sep 21, 2023

Unfortunately, we ran out of cruisers learning it.

WARSPITER · Sep 22, 2023

Don't worry, there were plenty left. Especially the light cruisers as the IJN was very much behind on those.

Shortround6 · Sep 22, 2023

The IJN had a light cruiser "gap" but this was unknown to the Allies in 1940-41-42.
The last of the "old" light cruisers was Naka completed 11/30/25 and was purely WW I in concept.

The Mogami's (1935) with their 15 6.1 guns had "inspired" the US Brooklyn class but the Mogami's were given 10 8in guns in 1939-40 (?) and passed out of the light cruiser class and since the Japanese did not have an excess number of 8in Cruisers that left them short.

Japanese only built 5 real light cruisers during the war
1 at the end of 1942
3 during 1943
1 during 1944

And these had the firepower of an Arethusa (six 6in guns) so they didn't really make up for war losses.

Now the US also had a light cruiser gap. The US had no left over WW I cruisers but had 10 of the Omaha class. Then the Brooklyn's and then the Cleveland's and Atlanta's the started to trickle in during late 1942.

The British was the only fleet operating in Pacific in the late 30s with any post 1930 light cruisers aside from the Netherlands.

The Problem for the Japanese was that their old light cruisers were deficient in fire control and long range gunnery, and that their torpedo armament range was bit of an illusion.
Doesn't matter if the torpedoes can travel 40,000 meters if the cruisers (and destroyers) can't see 40,000 meters.

You need range finders and gun & torpedo directors high enough off the water to allow for range you want to fire at.
A few lookouts with binoculars are not fire control.

The night engagements suited the Japanese as they forced everybody to get closer.
Unfortunately in this hypothetical British vs IJN scenario the British have more radar and more experience with it than the US had and they had 18 modern (after 1930) Cruisers still afloat in 1942 (less damaged ones).
Superiority in one class of ships doesn't mean the British are going to win in all cases (or even 50%) but it does show that just substituting British for US ships is not going to give the same results.
Japanese light cruiser doctrine was also different than US or British. The Japanese didn't group their light cruisers together into squadrons or divisions. They spread them out as destroyer flotilla flag ships.

z42 · Sep 22, 2023

The Japanese hadn't developed rapid fire 6" guns, leaving their light cruisers outgunned by RN and USN light cruisers with a comparable number of tubes (just looking at volume of fire here, ignoring fire control). Which perhaps partly explains their apparent lack of enthusiasm for that class of ships.

Or if one looks at it the other way, they had for other reasons decided that they wanted to mostly concentrate on 8" cruisers, and thus didn't bother with developing a rapid fire 6" gun.

WARSPITER · Sep 22, 2023

Shortround6 said:
The Problem for the Japanese was that their old light cruisers were deficient in fire control and long range gunnery, and that their torpedo armament range was bit of an illusion.
Doesn't matter if the torpedoes can travel 40,000 meters if the cruisers (and destroyers) can't see 40,000 meters.

True.

z42 said:
The Japanese hadn't developed rapid fire 6" guns, leaving their light cruisers outgunned by RN and USN light cruisers with a comparable number of tubes (just looking at volume of fire here, ignoring fire control). Which perhaps partly explains their apparent lack of enthusiasm for that class of ships.

Good points.

Shortround6 · Sep 22, 2023

z42 said:
The Japanese hadn't developed rapid fire 6" guns, leaving their light cruisers outgunned by RN and USN light cruisers with a comparable number of tubes (just looking at volume of fire here, ignoring fire control). Which perhaps partly explains their apparent lack of enthusiasm for that class of ships.

Or if one looks at it the other way, they had for other reasons decided that they wanted to mostly concentrate on 8" cruisers, and thus didn't bother with developing a rapid fire 6" gun.

There are a number of reasons.

The Japanese could not actually build what they wanted, they could not afford it.
They had gone to the 5.5 in guns because the lighter weight shells were easier to manhandle to the guns from the hoists.
Now please note that this was a limit to the British 5.25in AA guns which failed to reach the desired rate of fire.
Getting the gun to fire at X rounds per minute is easy. getting it to fire at the same X number of rounds per minute at any practical elevation angle and at any point in train with tired (exhausted) wet/ cold crewmen after 10-20 minutes of serving the guns is hard part. You need many tons of power equipment to supply even 6in shells to guns.

The Japanese were restricted by treaties and just like other navies everybody jumped on the 8in band wagon for most of the 1920s and very early 30s. Most other navies didn't go back to the 6in cruisers until they had their quota of 8in cruisers either already built or completing.

If you are doing long range salvo firing the rate of fire slows down considerably. You are firing at the rate of the slowest gun on the ship and at somewhere around 15,000yds (Depending on gun) the time of flight is about 30 seconds. which means even with a salvo in the air you firing at 4 rounds per minute.
We are definitely getting into the close range gun battle vs long range battle here.

The Japanese built 20 3 gun turrets. after pulling them from the Mogami's they used 4 of them. They used some of the barrels as long range heavy AA guns but the waste of the turrets is notable.

For all of their emphasis on airpower Japanese Cruiser AA was pretty pathetic. It was also a bit wasteful as instead of accepting the loss of torpedo armament (or even the spare torpedoes) and just using the best AA guns they had they kept trying new guns but only mounting 4 on the Agano's didn't do much.
The Agano's were going in too many different directions at the same time.

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