ASW Statistics

[spence]

During the course of WW2 the IJN/IJNAF ASW assets sank 39 Allied submarines (33 US, 4 RN, 2 RNN). Some other Allied submarines were sunk as the result of marine accidents, mines, bombing in port and scuttling (a significant number of RNN subs during the fall of the DEI), and one by shore batteries(?).

According to the TROMs of IJN ships at CombinedFleet.com the IJN lost 80 escort type ships (about 60 of the heavily armed escort types like super Es) and 38 fleet destroyers to torpedo attack by Allied submarines (losses to other causes are excluded from the count).

So IRL the IJN traded ~3 escort vessels for every submarine they sank. Not too impressive.

On the other hand Allied ASW type ships or ships cooperating directly with a/c sank 73 IJN subs for the loss of 3 DDs (maybe 4 but USS Porter was probably sunk by an errant torpedo from a ditching TBF) and 2DEs. IJN subs lost to a/c operating alone, Allied submarines, mines, accidents or unknown causes are not counted here.

So the IJN lost ~14 subs sunk for each escort that IJN subs sank.

Through much of the war the Allies enjoyed operationally actionable intelligence regarding IJN and IJ merchant ship movements: probably contributed to the totally unbalanced results noted above.

[rustysi]

From what I've read over the years I've found that ASW operations in the IJN were not viewed favorable. These assignments were viewed as "beneath" many sailors and officers. Training and crews were of poor quality. I don't think their equipment (ASDIC) was up to par. Its also a matter of doctrine. There subs were for attacking combat vessels. Why should anyone fight differently? The Japanese bubble. The US even had trouble early on. Convoys, yeah right. We just got an early reality check, courtesy of the Nazis. US doctrine too was that the subs would scout (although this may have been changing a bit before the war) for the battle fleet. OK, where was that, bottom of Pearl. What's plan 'B'? Turn the subs loose. Even US equipment aided in convincnig Japan that she must be right. What was the dud rate for US torpedoes? I don't recall the loss rate of Japanese shipping in the first year of the war, but it wasn't very high. Bsides all that the war was going to be short. Why should Japan invest a great effort in ASW? Japan did finally get her wake up call. It was like many things in life... too little, too late. I believe the things I've postulated here had something to do with the loss disparity.

[Nami Koshino]

ORIGINAL: rustysi

What was the dud rate for US torpedoes? I don't recall the loss rate of Japanese shipping in the first year of the war, but it wasn't very high.

In 1942 struggling American submarines sank 884,928 tons of Japanese merchantmen. This only slightly exceeded Japanese prewar estimates and replacement tonnage, and so only provoked more complacency among the Japanese than alarm. Losses doubled dramatically the next year, but by then the window for reform had passed. Japan lost the unintended respite it had been granted before the US underwater assault really began in earnest with reliable torpedoes, greater numbers and more aggressive skippers. What she could have made with it is hard to say. I don't think it would have changed the outcome much.

Interesting numbers spence. I wonder what the escort/submarine ratios are for the Atlantic Theater?

[EHansen]

One thing you would not have seen in RL was IJA bombers trained and flying ASW patrols. There were built to bomb the enemy, not spend endless hours searching for enemy subs. That was a job for the IJN and even they didn't do it very rigorously. Not what we see in a game of WitP:AE.

[Numdydar]

ORIGINAL: rustysi

Its also a matter of doctrine. There subs were for attacking combat vessels. Why should anyone fight differently? The Japanese bubble.

While this is a common belief, there was no official document or policy that stated that the IJN subs were only allowed to attack combat vessels. What actually occured was that due to the Bushido code, Japanese sub commanders only wanted to attack combat vessels. Since the vast majority of the sub commanders thought this way it made it appear that it was an 'official' doctorine. When in fact it was not.

This is why the switch that was in WitP that forced IJN subs to only attack combat vessels was removed in WitP AE.

[Dixie]

ORIGINAL: Nami Koshino

Interesting numbers spence. I wonder what the escort/submarine ratios are for the Atlantic Theater?

According to U-boat.net, 257 Allied warships (of all types which includes LSTs etc, 136 escorts from a quick count) hit with 216 sunk by U-boats. The same site has U-boat losses to ships at 264 from 1,149 boats.


http://www.uboat.net/allies/merchants/warships.html

[decaro]

ORIGINAL: Numdydar

ORIGINAL: rustysi

Its also a matter of doctrine. There subs were for attacking combat vessels. Why should anyone fight differently? The Japanese bubble.

While this is a common belief, there was no official document or policy that stated that the IJN subs were only allowed to attack combat vessels. What actually occured was that due to the Bushido code, Japanese sub commanders only wanted to attack combat vessels. Since the vast majority of the sub commanders thought this way it made it appear that it was an 'official' doctorine. When in fact it was not.

This is why the switch that was in WitP that forced IJN subs to only attack combat vessels was removed in WitP AE.

That explains why the switch is gone, but is there a dice roll to determine if an IJN sub commander will actually attack a freighter or some other unworthy target?

Reminds me of the IJN sub commander in that WWII Spielberg comedy that shelled an industrial (amusement) park and sank a ferris wheel looking for something honorable to attack!

The movie bombed, but my sister and I always thought is was funny.

[rustysi]

Numdydar

OK maybe my term of doctrine in this sense was a bit overstated.


"While this is a common belief, there was no official document or policy that stated that the IJN subs were only allowed to attack combat vessels"

Well on this I guess we'll just have to disagree. The IJN in WWII prusued the doctrine of guerre d'escadre (fleet vs. fleet warfare), and this included their submarines. Two prime examples are Midway and the Solomons (remember the "Wasp").

"What actually occured was that due to the Bushido code, Japanese sub commanders only wanted to attack combat vessels."

This was true, but I believe there were other factors in play also. I remember reading somewhere long ago that Japanese sub doctrine DID in fact set limits on how many torpedoes were to be fired on what type of ship. Merchants were only allowed one each Type 95 oxygen-fuelled torpedo. So nothing officially (AFAIK) stated that merchy's were off limits. Although I think that such a limit would discourage a sub skipper from firing at such a target.

[Symon]

ORIGINAL: Numdydar
That explains why the switch is gone, but is there a dice roll to determine if an IJN sub commander will actually attack a freighter or some other unworthy target?

It's always a revelation to me how people who know nothing about the code or the development process can make such sweeping and dispository statements. They could be psychic or psychotic or perhaps just be a psychedelic psyllid reachng for psychasthenia. Who knows. But I am in awe, simply in awe.

[Bullwinkle58]

ORIGINAL: rustysi

Numdydar

OK maybe my term of doctrine in this sense was a bit overstated.


"While this is a common belief, there was no official document or policy that stated that the IJN subs were only allowed to attack combat vessels"

Well on this I guess we'll just have to disagree. The IJN in WWII prusued the doctrine of guerre d'escadre (fleet vs. fleet warfare), and this included their submarines. Two prime examples are Midway and the Solomons (remember the "Wasp").

"What actually occured was that due to the Bushido code, Japanese sub commanders only wanted to attack combat vessels."

This was true, but I believe there were other factors in play also. I remember reading somewhere long ago that Japanese sub doctrine DID in fact set limits on how many torpedoes were to be fired on what type of ship. Merchants were only allowed one each Type 95 oxygen-fuelled torpedo. So nothing officially (AFAIK) stated that merchy's were off limits. Although I think that such a limit would discourage a sub skipper from firing at such a target.

One source I quickly found states that IJN subs sank 184 merchant ships for nearly a million tons of loss. (907,000 GRT) That ain't nothing. And it sure isn't a lot of COs violating orders.

I don't know if only one Type 95 was allowed per target. But if one hit a merchant it was going down most likely. Very substantial warheads.

[decaro]

ORIGINAL: Symon

ORIGINAL: Numdydar
That explains why the switch is gone, but is there a dice roll to determine if an IJN sub commander will actually attack a freighter or some other unworthy target?

It's always a revelation to me how people who know nothing about the code or the development process can make such sweeping and dispository statements. They could be psychic or psychotic or perhaps just be a psychedelic psyllid reachng for psychasthenia. Who knows. But I am in awe, simply in awe.

It was neither psychic or psychotic or even a declarative statement -- it was a query as shown by the question mark (?) at the end of the sentence.

And did you notice that you have attributed the quote to the wrong poster?

[mind_messing]

ORIGINAL: Symon

ORIGINAL: Numdydar
That explains why the switch is gone, but is there a dice roll to determine if an IJN sub commander will actually attack a freighter or some other unworthy target?

It's always a revelation to me how people who know nothing about the code or the development process can make such sweeping and dispository statements. They could be psychic or psychotic or perhaps just be a psychedelic psyllid reachng for psychasthenia. Who knows. But I am in awe, simply in awe.

The only solution to ignorance is access to information. If somebody in the know decided to kindly break down various aspects of the code, we'd all be happier and smarter. But nobody has bothered.

Seeing as there's been, what, three confirmed statements about the games code made by the developers (discounting stuff other than "that's broken") are you really suprised that the community attempts to divine the code from their own experiances?

[spence]

Whether or not IJN doctrine "allowed" sub commanders to attack "unworthy" targets such as freighters is actually irrelevant.

Compared to the Type VIIs and Type IXs employed by the Germans in the Atlantic IJN submarines were slower to submerge and less maneuverable and were demonstrably less effective in combat than those German ships.

To my mind the occasional success enjoyed by IJN subs such as the sinking of the Wasp (not so much the sinking of the Yorktown) has been allowed to completely overshadow performance that just wasn't all that good. Even including those spectacular successes (Wasp, Yorktown, Indianapolis, Juneau etc) into the statistical average means that the IJN lost 6-7 submarines for each success.

And that says nothing about the loss of 3+/- escort types for every Allied submarine that was sunk by their efforts.

[crsutton]

Radar made the difference. Well, sonar too, but radar above all. Subs could be effective without radar as long as the enemy did not have it, but surface ships were at a distinct disadvantage without it vs subs. And when the Allies subs eventually go excellent radar, then it was just not much of a match.