US torpedo failures and Japanese ASW policy

I was thinking that because of the failure of US torpedo's did Japan not take the threat of Subs as seriously as they might have if the failure had not happened. I know Japan was not ready, but would they have responded quicker if losses had been heavier earlier?

 

good question....one factor is, when did the subs really start doing a lot of patrols in the critical areas??...of course, they had more patrols/more longer range subs later in the war, nearer the home islands/critical areas...
even if the torpedoes worked, did they have enough subs active to arise fear in the Japanese? the Japanese were on a ''roll'', also, so they had other things on their mind...Takao probably knows the details...

 

The IJN was built around the doctrine of winning the "Decisive Battle". If US subs had been more effective early on they still would have had a hard time reacting to it as their force structure was not designed to do so. Nor would the losses at that point have made it easy to do so.

 

A combination of all the above and a bit more I think.

The torpedo failures were the last, and most frustrating, in a long list of issues for US Submarine forces in the first year and a half or so. As with all aspects, there were never enough boats early on and a good number were initially WWI design 'S Boats' ( due to shortages, they at least were spared the Mk 14 torpedo's). Then there was the learning curve as to where best to post them for a good war patrol.

Somewhat discounted because of the Bureau of Ordinance's effort to switch around blame for the faulty Mk 14's, was their contention that leadership and tactics were to blame. In truth there was some merit to this as in some accounts I have read that over reliance upon pre war tactics led to missed opportunities and there was a significant turnover in sub commanders who did not have 'the right stuff'. They were 4.0 in peacetime, but could not handle the rigors of modern submarine warfare. In reading Back from the Deep the captain of the USS Sailfish was a superb commander for a post sinking command, getting a 'jinxed' ship and crew ready for war, but after one or two patrol's had himself relieved because ke knew he did not have what it took. He went on to have a fine career in the surface navy.

On the balance side as lwd notes, Japan had a aggressive stance to naval warfare that only reinforced the perception that commerce raiding was not hurting them. Add to that a near pathological unwillingness to accept that a mistake was ever made and you have a recipe for catastrophe.

 

that late?? did they not learn from history?? when did convoys and escort start? WW1?

 

Well they really didn't have much to use for convoy escorts. Their DDs were pretty much dedicated to fleet ops and like I mentioned earlier were optimized for their role in the "Decisive Battle". They did start building escorts but by the point they did the limitations of their resources and industry put a pretty tight limit on them.

 

I disagree with the others and say: Yes, they would have. Because they did react to the sub threat.

With the pre-war(!) Shimushu class escorts. They could have build more of them sooner or converted their older destoryers along the lines of the V&W class escorts. Eventually they did build several classes of escorts like the Shimushus, fast DE, slow corvettes and even a purpose designed ASW aircraft. Much of this was begun at a time when US torpedoes were still malufunctioning.

The US submarine threat was increasing faster though. AFAIK it was a combination of factors. New boats took some time to be completed, the advance of the ground forces provided the subs with bases much closer to the area of operations and the debugging of the torpedoes. And all this happened together, didn't it? In mid 1943 the top brass finally admitted the "fish" were flawed, the same same year the Gato and Baleo class subs were being comissioned in large numbers and the Allies gained ground in both PGN, the Solomons and the Central Pacific.

As a result sinkings suddleny skyrocketed if I recall Clay Blair(Silent Victory) correctly.

 

No one is saying that they wouldn't have reacted the question is just how much could they have reacted? It's clear that they were still wed to the "Decisive Battle" doctrine through out much if not all of 42 and perhaps past then. The old DD's were kept pretty busy in any case weren't they? Nor did they have a huge surplus of resources to build new vessels and planes. So what could and would they have sacraficed for increased ASW? Note that more losses of transports makes this problem worse as well.

 

Steve asked if Japan would they have responded quicker if losses had been heavier earlier.

The lead ship of the 14 vessel Etorofu-class was laid down in March 1942. The lead ship of the next class and the development of the Kyushu Tokai was also begun in 1942. While the IJN indeed focused on the "Decisive Battle" you can't they that they ignored submarines. You are right that something else has to go if additional ASW ship are built and it was fleet destroyers. The 1943 Tachibana class was a radical departure from previous DD classes.

 

Well Marcus,

For all intents and purposes, Japanese convoy escorts were ignored. Just because the Japanese ordered a handful of convoy escorts(at a number that was woefully inadequate) does not mean that they were aware that there even was or would be a problem. After all, the war was supposed to be over before America could bring it's full muscle to bear. However, some escorts would be required for more important convoys, and for harbor defense.

Fleet destroyers did not "go" as you so glibly presume, but continued to be built, right up until the end of the war for the Akizukis. What they did do was shift from an anti-surface platform to an anti-air platform.

The Tachibana class were an improvement of the previous Matsu class "destroyers"(and I always choke at calling these ships "destroyers"). While the Matsu class was a radical departure from previous designs, it was because they could be produced at a faster rate than previous Japanese destroyers, not that they were necessarily better at ASW. Thus, the Japanese would get more hulls in the water quicker than with other more combat capable destroyers.

 

The IJN ordered more escorts less than six months after the war had begun and kept on ordering. Doesn't look like they ignored the problem.

Read the second sentence too and Steves question:

With the resources that went into the Tachibana class they could have built even more fleet DD. Thus a part of the fleet DD production was "sacraficed for increased ASW".

 

When exactly were the Matsu and achibana class designed? Apparently they were ordered in 42 but was it late 42? Combined fleet seems to indicate that they were designed based on experiances in the Solomon's and elsewhere and obviously weren't optimized for surface combat but had a better AA suite. As such it's not clear to me that a moderate increase in losses due to subs in early 42 is going to speed up the procurement of such a design.

 

Late-42...September 21, 1942, was when the Modified Circle 5 was approved. The Matsu would not be laid down until August 8, 1943. While, the Tachibana would not be laid down until July 8, 1944.

 

By my count, September 21, 1942, is a good ten months, and almost eleven months after the war began...

Which second sentence? There are a lot of them...

The second sentence of your response - concerning the Etorofu class, or the second sentence of your second paragraph - concerning the "lead ship of the next class" and the development of the Kyushu Q1W "Tokai".

No.

The Matsu class were designed specifically to get destroyer hulls in the water faster than the larger Type A or Type B destroyers. The Type Ds were "Jack of all trades, masters of none," destroyers. They could engage surface, sub-surface, and anti-air targets, however, they did not really excel in any one area.

So, in the end, "nothing was being sacrificed for increased ASW". However, sacrifices were being made to get destroyer hulls into commission faster than normal.

 

The lead ship of theEtorofu-class was laid down in March 1942, not September.

I concur.

 

They may have been laid down in March, 1942, but they were ordered back on September 21, 1941, as part of the "Circle Urgent" program. There were 30 Etorofu class ordered(hull numbers 310-339) at this time, and those vessels ordered would encompass the Etorofu(14 vessels), Mikura(8 vessels), and part of the Ukuru class(8 vessels).

Thus, your statement,

is a false one...

Japan would not order more ship until September 21, 1942, with the passing of the Modified Circle Five Program.

 

So after Midway and after the initial battles off Gaudalcanal. Fuel constraints may also have been impacting operations significantly by then as well. The fact that carriers (air battles) were going to be significant was obvious by this point and the relevance of the Decisive Battle doctrine would surely be in question. So going to building more destroyer class hulls based on a general purpose design rather than ones oriented toward surface warfare looks warrented. Would an increase in the effectiveness of US subs in the first half of 42 been enough to push such a design several months earlier? Certainly not clear at this point.

 

Yes, the need for more and more carriers had become obvious to the Japanese, however, fuel constraints might have been having a slight effect at the time, but it was not being considered in the Japanese 1942 shipbuilding program. With the same stroke of the pen that authorized the 42 Matsu/Tachibana class, also authorized 15 Unryu class carriers, and 5 improved Taiho (G-15 class) carriers. Also authorized were 23 improved Akizuki class destroyers, and 8 improved Yugumo class destroyers. So the Japanese are looking to construct a new carrier heavy fleet, but the new destroyer to carrier ratio works out to slightly more than 3.5 new destroyers per carrier...and this does not take into consideration the need to replace destroyer losses. As to the "Decisive Battle", it still held quite a bit of relevance, however, it would be the new carriers that would be the final arbiters in this Battle and not, as originally intended, the Japanese battleships.

As to what destroyers the Japanese should build, that could be a book subject. By this time, the Japanese were starting to feel the losses of their destroyers, and the surface actions in the Solomons was building. On one hand, the Matsu class can be seen as being better able to deal with the anti-air threat than the Japanese super destroyers. Further, the Matsu class could take over the general escort duties, thereby freeing the Japanese Supers for actions in the Southwest Pacific. Also, the Matsu class could be constructed at a faster pace, and had half the tonnage than the Supers or Akizuki class, so the Japanese could get more hulls in the water, although those hulls would be less combat efficient than the Supers or Akizukis. Regardless, the Japanese had already begun their downward shipbuilding spiral.


Now the 64,000 dollar question...Would an increased effectiveness been enough to push the Matsu class design ahead several months earlier.
On the face of it, I would have to say no...Unless the American submarine campaign substantially more effective than it historically was. However, I do not see the American submarines being substantially more effective for two basic reasons...One - Numbers, the American just did not have submarine in sufficient quantities until maybe mid-'43, definitely by 1944. Two - Experience, the American submarine commanders were still unlearning all their pre-war training and developing their own tactics that would make them successful from 1943 on. There are plenty of lesser factors such as: The Japanese are still building their "main fleet" to engage the Americans, radar had not yet been widely fitted to American submarines, etc. So without a really major change to US submarine warfare, and I don't see better torpedoes as having the needed effect, the Japanese will stay with their major fleet program of 1942-43, as opposed to the programs of 1943-44 and 1944-45, which was composed almost exclusively of submarines, and escort vessels.

Finally, I am of the opinion that the Matsu class was the direct result of the Japanese having to patrol a far greater area with a presumably larger fleet, as opposed to the idea that the Matsu was the direct result of the US Submarine Campaign. Indeed, a substantially more effective submarine campaign would argue against the building of the Matsu class, and a far greater increase in the production of the various Ch- and Cha- classes of submarine chasers.

 

I found an interesting quote here:
http://www.combinedfleet.com/BorneoOil.htm

Which implies the real danger of US subs might not have been clear even with considerably greater effect. By the way the above is from a series of articles at:
http://www.combinedfleet.com/Oil.htm

In relation to the impact of oil on the war at that point I seem to recall reading that many of the IJN ships at Midway had come from the Dutch East Indies as they could use that oil unrefined if refined oil wasn't available and both were in greater supply there than in the home islands. If so oil was already impacting operations. Whether or not and how it was impacting ship design is an interesting and open question in mid 42 from what I can see. Certainly by late 42 I would think it would be of some import but then there's the question of just how much information got to the people writing the specs and designing the ships. From what I've read they kept the info about what happened at Midway pretty close for some period after the battle. Info on the oil supply may not have been shared well either.