stock torp dud rate

[Enforcer]

In stock 2 what is the usn torp dud rate?

[spence]

Scenario 2 has the same dud rate as Scenario 1. The dud rate in DBB is also the same. The only Scenario of which I am aware in which the torpedo dud rate is the Big B Mod. In that one the dud rate is adjusted to 50% in April 42, again in Jan 43 (IIRC to 40%) and finally in Oct 43 (10%). According to JANAC sources Japanese ship losses thru Oct 43 pretty much track with his revised dud rates and the "Stock rates" make the historical number of Japanese ships sunk/damaged impossible.

[Chickenboy]

ORIGINAL: spence
According to JANAC sources Japanese ship losses thru Oct 43 pretty much track with his revised dud rates and the "Stock rates"

Not sure what you mean by this. Blair's work (Silent Victory) shows that no significant improvement in Mk. 14 torpedo performance was realized until September-October 1943-just like in stock games (sc. 1 or 2). Allied attrition of Japanese shipping IRL versus game comparatives is based upon many, many more factors than the dud rate-most of these factors are subject to gameplay deviations versus IRL and cannot be legitimately compared without this caveat.

[Lokasenna]

ORIGINAL: Chickenboy

ORIGINAL: spence
According to JANAC sources Japanese ship losses thru Oct 43 pretty much track with his revised dud rates and the "Stock rates"

Not sure what you mean by this. Blair's work (Silent Victory) shows that no significant improvement in Mk. 14 torpedo performance was realized until September-October 1943-just like in stock games (sc. 1 or 2). Allied attrition of Japanese shipping IRL versus game comparatives is based upon many, many more factors than the dud rate-most of these factors are subject to gameplay deviations versus IRL and cannot be legitimately compared without this caveat.

You could put the dud rate at zero and still not be able to achieve the level of shipping sunk in real life.

[geofflambert]

Japanese doctrine is a factor, and it depends on the player. Japanese historical doctrine couldn't be worse as far as reducing shipping losses.

[spence]

JANAC - Joint Army Navy Assessment Committee. While the data may be inaccurate/incomplete since the it was compiled fairly immediately after the Japanese surrender (1947) the overall losses of IJN ships and Japanese merchant ships to submarine attack should be somewhat near the JANAC losses. With an 80% dud rate extending for the first year+ such losses are impossible.

The torpedo crisis within the USN was the result of 3 different and unrelated problems. They were corrected at different times and by different persons.

[LargeSlowTarget]

ORIGINAL: Chickenboy

ORIGINAL: spence
According to JANAC sources Japanese ship losses thru Oct 43 pretty much track with his revised dud rates and the "Stock rates"

Not sure what you mean by this. Blair's work (Silent Victory) shows that no significant improvement in Mk. 14 torpedo performance was realized until September-October 1943-just like in stock games (sc. 1 or 2). Allied attrition of Japanese shipping IRL versus game comparatives is based upon many, many more factors than the dud rate-most of these factors are subject to gameplay deviations versus IRL and cannot be legitimately compared without this caveat.

+1

The story of the Mark 14 torpedo is pretty well-known - faulty depth mechanism, faulty magnetic exploder, faulty contact exploder - and one problem was hiding the others.

The question is what justifies the first drop in the dud rate in April 42 in the Big B mod?

According to various sources and accounts about the US submarine warfare in WWII, the first problem to be identified and solved was the depth mechanism.

Long suspected by skippers, field-tests in June 1942 provided proof of deep running, followed by more tests by the Bureau of Ordnance - which admitted officially in August 1942 that the Mark 14 torpedoes ran deep and instructed submarine skippers to adjust depth settings accordingly as a stopgap measure. The problem with the depth running mechanism itself wasn't solved until summer 1943.

So it seems that the first - slight - reduction in the dud rate should occur in August 1942 - not in Jan 1943 like in stock, but neither in April 1942 like in Big B mod.

[spence]

IMHO something changed earlier than August 42. If submariners had been dependent on the Bureau of Ordinance to fix their problems we would almost certainly still be waiting for them to have found something wrong with the Mark 14.

The losses of merchant ships sunk attributed to US submarines up until Jan 44 in the JANAC papers are as follows (no IJN warships/auxiliaries included in totals, sinkings by Allied submarines are not included, no unknown causes included but ships lost presumed sunk by a US submarine are included)
Dec 41 - 3
Jan 42 - 6
Feb 42 - 4
Mar 42 - 11
Apr 42 - 5
May 42 - 21
Jun 42 - 6
Jul 42 - 9
Aug 42 - 18
Sep 42 - 11
Oct 42 - 27
Nov 42 - 13
Dec 42 - 15
Jan 43 - 23
Feb 43 - 9
Mar 43 - 22
Apr 43 - 18
May 43 - 30
Jun 43 - 23
Jul 43 - 17
Aug 43 - 18
Sep 43 - 31
Oct 43 - 26
Nov 43 - 46
Dec 43 - 29

[spence]

If the variance between individual months is ignored but the totals for 3 consecutive month periods are looked at it becomes evident that something important changed in the spring of 1942. A further change seems to have occurred in the late summer of 1942.

[Ian R]

Didn't we have a thread on this a couple of months ago?

Lockwood ordered some changes for the PH based subrons that were not implemented in the SWPAC subrons till months later. I forget the name of the guy who succeeded Lockwood at Fremantle when the latter went to PH, but he invented the magnetic exploder or something like that. Kinkaid ordered him to ditch it in the end.

The funny thing is, the magnetic exploder might have worked better if the sub skippers put the torpedoes under the target, instead of taking hull shuts

[BBfanboy]

ORIGINAL: spence

If the variance between individual months is ignored but the totals for 3 consecutive month periods are looked at it becomes evident that something important changed in the spring of 1942. A further change seems to have occurred in the late summer of 1942.

That could be explained by the installation of radar in some boats, the opening of new sub bases closer to the front and Japanese moving forward into areas already being patrolled. The May 1942 spike is about the time the Japanese moved into the Solomons after the Coral Sea battle.

[Trugrit]

From what I understand of multiple sources:

The Mark 14 torpedo had four major flaws.

• It tended to run about 10feet deeper than set.
• The magnetic exploder often caused premature firing.
• The contact exploder often failed to fire the warhead.
• It tended to run "circular".”

http://everything.explained.today/Mark_14_torpedo/

Depth Problem:
“By August 1942, the faulty running depth situation was resolved”

Magnetic Exploder Problem:
In late June 1943, Rear Admiral Lockwood (by then COMSUBPAC) asked Commander-in-Chief of the Pacific Fleet (CINCPAC)
Chester Nimitz for permission to deactivate the magnetic exploders.

The next day, 24 June 1943, CINCPAC ordered all of his submarines to deactivate the magnetic exploder.

“Inactivation of the magnetic influence feature stopped all the premature explosions.”

Contact Exploder:

Final full solution:
“In September 1943, the first torpedoes with new contact pistols were sent to war.”

"After twenty-one months of war, the three major defects of the Mark 14 torpedo had at last been isolated.
Each defect had been discovered and fixed in the field—always over the stubborn opposition of the Bureau of Ordnance."

The circular problem was minor.

I would say three historical reductions.

August 1942.
June 1943.
September 1943.

I'm not sure that would work well in the game.
This is a game after all and not history.

I would tend go with Big B. There are other factors.
As sub commanders and crews got more experience in the war their
success rates would improve even with torpedo defects.

In the game you have to factor in other variables.

[Kull]

ORIGINAL: Trugrit

In the game you have to factor in other variables.

To me, the focus on dud rates seems a bit overblown. What about:

- Allied player ability to ditch bad sub commanders for good ones IMMEDIATELY?
- Allied players using S-boats and Dutch subs essentially as replacements for Fleet Boats (because with foreknowledge you know their torpedoes work)?
- Japanese players using convoys right from Day 1?
- Japanese players converting a ton of Cargo ships to PBs right away because they also know that Fleet boats have lousy torpedoes, so the most important thing is to prevent surface attacks?
- Japanese players intensively training their air crews in Naval and ASW search right from the get-go because they KNOW how deadly submarines will become?
- Allied players unable to get the level of late war intelligence that told sub commanders EXACTLY where to find the Japanese convoys and their pathetic escorts?
- Absence of the "wolfpack" ability which allowed the Allies to decimate those known convoys in their known locations?

It goes on and on, really. Tweaking one issue without accounting for the others is just going to shift the imbalance, not solve a problem.

[obvert]

ORIGINAL: Lokasenna

ORIGINAL: Chickenboy

ORIGINAL: spence
According to JANAC sources Japanese ship losses thru Oct 43 pretty much track with his revised dud rates and the "Stock rates"

Not sure what you mean by this. Blair's work (Silent Victory) shows that no significant improvement in Mk. 14 torpedo performance was realized until September-October 1943-just like in stock games (sc. 1 or 2). Allied attrition of Japanese shipping IRL versus game comparatives is based upon many, many more factors than the dud rate-most of these factors are subject to gameplay deviations versus IRL and cannot be legitimately compared without this caveat.

You could put the dud rate at zero and still not be able to achieve the level of shipping sunk in real life.

+1

The real "problem" in game isn't just the dud rate.

1. The IJN in game can be used more effectively to convoy ships and hunt subs often with AV or AMC moving with them that include possible search and ASW floatplanes. The IJ player also doesn't need to use the most dangerous convoy routes away from LBA.

2. The ASW in game is miles better than in the war due to the ability to both train ASW pilots to expert levels and to use the IJAAF in concert with the IJN to provide much more extensive coverage of convoy routes and bigger, better platforms for sub killing. (I saw rader early on using Sallys on 50%ASW, 30% train, 20% rest and by about June 42 he had 70 skill ASW pilots flying all over the map basically making certain areas completely off-limits to Allied subs. I copied that. It works).

3. The IJ doesn't need to use ships in the way they did in the war, sending them inefficiently out with supplies and back empty, or vice versa, out empty to go pick up supplies. I find a good portion of my merchant marine as Japan sits idle in the mid-war, and I prioritize only the most efficient haulers to bring the goods back I need and always load them up on the way out (excluding the fuel/oil tankers).

4. The IJN in games often ends up with a plethora of small, older DDs, TBs, P, and E class ships in the mid-war which aren't critically needed for anything and can become sub-hunters with increasing success as the better classes become available in numbers. Once the Es start flowing in 43 Allied subs are in trouble.

5. The IJ can move more overland than was probably possible in the war, and especially across China can set this up fairly easily.

[obvert]

ORIGINAL: Kull

ORIGINAL: Trugrit

In the game you have to factor in other variables.

To me, the focus on dud rates seems a bit overblown. What about:

- Allied player ability to ditch bad sub commanders for good ones IMMEDIATELY?
- Allied players using S-boats and Dutch subs essentially as replacements for Fleet Boats (because with foreknowledge you know their torpedoes work)?
- Japanese players using convoys right from Day 1?
- Japanese players converting a ton of Cargo ships to PBs right away because they also know that Fleet boats have lousy torpedoes, so the most important thing is to prevent surface attacks?
- Japanese players intensively training their air crews in Naval and ASW search right from the get-go because they KNOW how deadly submarines will become?
- Allied players unable to get the level of late war intelligence that told sub commanders EXACTLY where to find the Japanese convoys and their pathetic escorts?
- Absence of the "wolfpack" ability which allowed the Allies to decimate those known convoys in their known locations?

It goes on and on, really. Tweaking one issue without accounting for the others is just going to shift the imbalance, not solve a problem.

The frustration is that Allied subs were a very potent weapon during the war and that success can, as you've pointed out in a few of your listed items, be thwarted in game. The Allied subs should be dangerous by mid-43, but by this time the IJN has already reduced the fleet through focus on the sub war and are well set up to make the remaining years difficult on the silent service.

It just is the game, and no one is changing anything at this stage unless it's in a mod. But, you can do some modding and make things a bit different. [;)]

[Chickenboy]

ORIGINAL: spence

IMHO something changed earlier than August 42. If submariners had been dependent on the Bureau of Ordinance to fix their problems we would almost certainly still be waiting for them to have found something wrong with the Mark 14.

The losses of merchant ships sunk attributed to US submarines up until Jan 44 in the JANAC papers are as follows (no IJN warships/auxiliaries included in totals, sinkings by Allied submarines are not included, no unknown causes included but ships lost presumed sunk by a US submarine are included)
Dec 41 - 3
Jan 42 - 6
Feb 42 - 4
Mar 42 - 11
Apr 42 - 5
May 42 - 21
Jun 42 - 6
Jul 42 - 9
Aug 42 - 18
Sep 42 - 11
Oct 42 - 27
Nov 42 - 13
Dec 42 - 15
Jan 43 - 23
Feb 43 - 9
Mar 43 - 22
Apr 43 - 18
May 43 - 30
Jun 43 - 23
Jul 43 - 17
Aug 43 - 18
Sep 43 - 31
Oct 43 - 26
Nov 43 - 46
Dec 43 - 29

Nobody is disputing the JANAC numbers of Japanese ships sunk by American submarine warfare, spence. What is disputable is the sole reliance on the 'dud rate' of Mk.14s to try to get the game to mirror reality.

In reality, the sharpening of the American submarine 'spear' was multifactorial. Laconic or passive skippers were ruthlessly replaced in the field. Technological advances in radar were implemented that allowed American submarines to more effectively attack enemy shipping. As the war progressed increasingly actionable intelligence / SigInt was passed along to submarines to allow them to be at the right place and the right time for interception of Japanese shipping. More numbers of more capable fleet submarines (e.g., Balao, Gato classes) were brought into theater that carried more torpedoes and could loiter in target-rich waters longer than before. More AS and other support ships were brought into play that shortened the distance that submarines had to cover to get into prime hunting grounds, etc. etc.

At the same time, Japanese ASW measures did not keep up with American improvements in submarine warfare. Convoy systems-except for the most important troop transports or surface combat armadas-were late in arriving. Comparatively few Japanese TFs were escorted by surface ships. Dedicated aerial ASW platforms were few and far between until late war (when it was too late anyways).

In the game, few Japanese players allow for the lethargy and inattentiveness that the RL Japanese used in ASW. Nearly all Japanese players use convoy methods for their most valuable cargoes. ASW aerial reconnaisance is-IMO-much more important in the game than it was IRL. Escort shipping is much more commonplace for all make of convoys than IRL. Many Japanese players train up IJAAF(!) air forces for ASW roles as well-a laughably ahistoric happenstance. Alternative day 1 strikes on Manila reduce available Allied submarines for the early war in many games as well.

All these factors should impact how the game approaches the JANAC figures. Using JANAC figures alone or assuming that decreasing the dud rate = JANAC levels of success with the Allied submarine effort belies the importance of these other variables.

As for whether Allied historical success would be 'impossible' to replicate, I don't know. You'd need to undo all of the player-determined improvements in Japanese ASW AS WELL AS assume a more passive Allied approach to submarine warfare to compare meaningfully. Do you know any Allied players that *don't* replace their poorly rated captains ASAP? Maybe even faster than IRL? Because I don't. The equation of Allied submarine effectiveness is a multivariable equation. Changing one variable-or ascribing the value due to one variable-without taking the others into account is fallacious.

ETA: After I posted, I noticed that others like Kull had already said exactly the same thing I did. Think of all the time I could have saved if I just "+1"ed his post. [:D]

[Zorch]

ORIGINAL: Chickenboy

ORIGINAL: spence

IMHO something changed earlier than August 42. If submariners had been dependent on the Bureau of Ordinance to fix their problems we would almost certainly still be waiting for them to have found something wrong with the Mark 14.

The losses of merchant ships sunk attributed to US submarines up until Jan 44 in the JANAC papers are as follows (no IJN warships/auxiliaries included in totals, sinkings by Allied submarines are not included, no unknown causes included but ships lost presumed sunk by a US submarine are included)
Dec 41 - 3
Jan 42 - 6
Feb 42 - 4
Mar 42 - 11
Apr 42 - 5
May 42 - 21
Jun 42 - 6
Jul 42 - 9
Aug 42 - 18
Sep 42 - 11
Oct 42 - 27
Nov 42 - 13
Dec 42 - 15
Jan 43 - 23
Feb 43 - 9
Mar 43 - 22
Apr 43 - 18
May 43 - 30
Jun 43 - 23
Jul 43 - 17
Aug 43 - 18
Sep 43 - 31
Oct 43 - 26
Nov 43 - 46
Dec 43 - 29

Nobody is disputing the JANAC numbers of Japanese ships sunk by American submarine warfare, spence. What is disputable is the sole reliance on the 'dud rate' of Mk.14s to try to get the game to mirror reality.

In reality, the sharpening of the American submarine 'spear' was multifactorial. Laconic or passive skippers were ruthlessly replaced in the field. Technological advances in radar were implemented that allowed American submarines to more effectively attack enemy shipping. As the war progressed increasingly actionable intelligence / SigInt was passed along to submarines to allow them to be at the right place and the right time for interception of Japanese shipping. More numbers of more capable fleet submarines (e.g., Balao, Gato classes) were brought into theater that carried more torpedoes and could loiter in target-rich waters longer than before. More AS and other support ships were brought into play that shortened the distance that submarines had to cover to get into prime hunting grounds, etc. etc.

At the same time, Japanese ASW measures did not keep up with American improvements in submarine warfare. Convoy systems-except for the most important troop transports or surface combat armadas-were late in arriving. Comparatively few Japanese TFs were escorted by surface ships. Dedicated aerial ASW platforms were few and far between until late war (when it was too late anyways).

In the game, few Japanese players allow for the lethargy and inattentiveness that the RL Japanese used in ASW. Nearly all Japanese players use convoy methods for their most valuable cargoes. ASW aerial reconnaisance is-IMO-much more important in the game than it was IRL. Escort shipping is much more commonplace for all make of convoys than IRL. Many Japanese players train up IJAAF(!) air forces for ASW roles as well-a laughably ahistoric happenstance. Alternative day 1 strikes on Manila reduce available Allied submarines for the early war in many games as well.

All these factors should impact how the game approaches the JANAC figures. Using JANAC figures alone or assuming that decreasing the dud rate = JANAC levels of success with the Allied submarine effort belies the importance of these other variables.

As for whether Allied historical success would be 'impossible' to replicate, I don't know. You'd need to undo all of the player-determined improvements in Japanese ASW AS WELL AS assume a more passive Allied approach to submarine warfare to compare meaningfully. Do you know any Allied players that *don't* replace their poorly rated captains ASAP? Maybe even faster than IRL? Because I don't. The equation of Allied submarine effectiveness is a multivariable equation. Changing one variable-or ascribing the value due to one variable-without taking the others into account is fallacious.

ETA: After I posted, I noticed that others like Kull had already said exactly the same thing I did. Think of all the time I could have saved if I just "+1"ed his post. [:D]

+1! [:D]

[fcooke]

Ian - I think the SWPAC admiral you are referring to is Christie...

I went to my sister's for Thanksgiving this year. In Plymouth Massachusetts (kinda funny if one knows the history of turkey day). Anyway I was driving up I-95 and realized I would be going by the US sub museum so decided that would be a good pit stop. Anyway, they had a MK 14 on display and IIRC the info sheet said it was in service until the late 70s. I was shocked it hung around that long [X(]

I had hoped to stop at Fall River on the way back but I was racing against a snow storm, so that didn't happen. Too bad, I think it has been about 30 years since I last visited Big Mamie.

edited to correct Ian's name.

[Lokasenna]

ORIGINAL: obvert

ORIGINAL: Lokasenna

ORIGINAL: Chickenboy




Not sure what you mean by this. Blair's work (Silent Victory) shows that no significant improvement in Mk. 14 torpedo performance was realized until September-October 1943-just like in stock games (sc. 1 or 2). Allied attrition of Japanese shipping IRL versus game comparatives is based upon many, many more factors than the dud rate-most of these factors are subject to gameplay deviations versus IRL and cannot be legitimately compared without this caveat.

You could put the dud rate at zero and still not be able to achieve the level of shipping sunk in real life.

+1

The real "problem" in game isn't just the dud rate.

1. The IJN in game can be used more effectively to convoy ships and hunt subs often with AV or AMC moving with them that include possible search and ASW floatplanes. The IJ player also doesn't need to use the most dangerous convoy routes away from LBA.

2. The ASW in game is miles better than in the war due to the ability to both train ASW pilots to expert levels and to use the IJAAF in concert with the IJN to provide much more extensive coverage of convoy routes and bigger, better platforms for sub killing. (I saw rader early on using Sallys on 50%ASW, 30% train, 20% rest and by about June 42 he had 70 skill ASW pilots flying all over the map basically making certain areas completely off-limits to Allied subs. I copied that. It works).

3. The IJ doesn't need to use ships in the way they did in the war, sending them inefficiently out with supplies and back empty, or vice versa, out empty to go pick up supplies. I find a good portion of my merchant marine as Japan sits idle in the mid-war, and I prioritize only the most efficient haulers to bring the goods back I need and always load them up on the way out (excluding the fuel/oil tankers).

4. The IJN in games often ends up with a plethora of small, older DDs, TBs, P, and E class ships in the mid-war which aren't critically needed for anything and can become sub-hunters with increasing success as the better classes become available in numbers. Once the Es start flowing in 43 Allied subs are in trouble.

5. The IJ can move more overland than was probably possible in the war, and especially across China can set this up fairly easily.

I'm of the opinion that it's entirely due to how subs attack in the game. Or rather, that while player doctrines make some difference vs. what happened in reality, they would not account for anywhere near the total.

Simply having a single escort, a tuna boat with a gun on it, in a TF is enough to prevent a submarine from attacking on the surface.

Submarines only attack 1 target at once, and torpedoes fired at one target can have no "contingency targets" in the game (a target that's behind another one on the torpedo's path).

Submarine attacks rely on the same DL abstractions that work perfectly fine for surface and air actions, and there is no way to make them shadow any contacts other than the reaction abstraction (for which subs are limited to 1 hex).

[Lokasenna]

ORIGINAL: spence

IMHO something changed earlier than August 42. If submariners had been dependent on the Bureau of Ordinance to fix their problems we would almost certainly still be waiting for them to have found something wrong with the Mark 14.

The losses of merchant ships sunk attributed to US submarines up until Jan 44 in the JANAC papers are as follows (no IJN warships/auxiliaries included in totals, sinkings by Allied submarines are not included, no unknown causes included but ships lost presumed sunk by a US submarine are included)
Dec 41 - 3
Jan 42 - 6
Feb 42 - 4
Mar 42 - 11
Apr 42 - 5
May 42 - 21
Jun 42 - 6
Jul 42 - 9
Aug 42 - 18
Sep 42 - 11
Oct 42 - 27
Nov 42 - 13
Dec 42 - 15
Jan 43 - 23
Feb 43 - 9
Mar 43 - 22
Apr 43 - 18
May 43 - 30
Jun 43 - 23
Jul 43 - 17
Aug 43 - 18
Sep 43 - 31
Oct 43 - 26
Nov 43 - 46
Dec 43 - 29

Using the numbers that you cited, I don't see any obvious difference in trend until August '42.

Also, did you adjust for number of sub patrols? More subs were coming online in spring and summer of '42. Obviously, there would be more attacks (and more successes) if there were more subs patrolling.