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RE: stock torp dud rate - 12/10/2019 9:45:00 AM

obvert

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quote:

ORIGINAL: ITAKLinus

Ohhhhhhhh ok I see.

Nevermind.

My understanding of the issue is that subs are not working because of a-historical behaviours from players rather than poor designing.

Now, my personal position is that the most game-changing element of the ASW is the possibility to devote huge IJAAF assets to it. In line of principle one can do the same using IJNAF assets, but using Betties/Nells for ASW, for example, has a clear and relevant cost-opportunity, which is much lower in case of, say, IJAAF Sallies.
Thus, my first move to approach the issue would be to limit the amount of IJAAF dedicated air assets through an HR, which is also quite easy to put in place and monitor.

Sure. You can do that. We could try to HR the complete separation of IJAAF from IJN operations, but this would be very hard to both organise and monitor. In reality they most often operated from different airfields, with different support crews and had different objectives. But ... there were also transports the IJA was in charge of running, and some other ships like the late war CVEs. So how do you deal with that? Could IJAAF patrol to support their own transports bt not those carrying naval supplies, equipment or troops?

Most of this historically "accurate" detail is impossible to model in game, and too much to add to the already complex environment.

quote:

Second issue I see is the terrible quality of many captains. In this case, an easy modification to the game would be to simply have by default very aggressive captains to USN subs since 7-DEC.
It can be done in game by players but we all know that paying PPs for USN subs isn't a priority for most of the allied commanders.

You could do that, but why? The USN subs didn't perform well in the beginning of the war due to several factors, the captains and their choices being part of that. It's hard to argue we should HR to be more historically accurate on one hand and less on another to produce a more effective USN sub presence.

If the USN had working subs in the beginning it could mess up the balance in terms of the IJ getting the SRA locked up early.

quote:

A third, and eventually last, element I'd give a try is a limitation through HR of the number of ships converted to PBs per-year.

Again, why? Firstly the IJ did modify a lot of ships into escorts and pickets. Secondly these are often valuable targets in themselves, the Ansyu-C PBs are worth 10 VPs, more than many merchants and DDs. So I want to sink those. Make more please.

The fun of playing the IJ is the modification of what was possible. Ships are a fascinating place to make the campaign your own and choose how you want to play.

quote:

I think that these very few modifications can have major impacts on sub warfare without the need of re-designing too many things. They're pretty easy to implement. I think that limiting IJAAF ASW is the key, also.

I like some of the other modifications that could be done through modding actual equipment (dud rates decreasing slightly earlier, accuracy of ASW for IJ DCs lessening at depth, perhaps making air search radar more effective for the USN, increasing torpedo explosive effectiveness).

Part of the fun though is to also change the IJ doctrine to allow some of the things that actually work. It would just be nice if some factors were altered so that air and naval ASW didn't have such a huge effect on limiting the USN sub fleet as the game moves into the mid-war years.

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RE: stock torp dud rate - 12/10/2019 10:34:00 AM

ITAKLinus

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I play both sides as well and I know how frustrating US subs are (and how good Dutch are, also).

My point of view comes from three basic elements:
A) I want the simplest possible changes to be made to the game
B) I want to reward a scrupulous Japanese player
C) I don't want to alter the balance for other elements

Now, if you consider for example the proposal made in the topic of increasing the BANG of torpedoes, you have that many warships will have far higher damages than in stock game. Fair enough, but it's a relevant alteration to game mechanics.
It's just an example, of course.

My entire opinion on the topic is that the current results are somehow the product of an a-historical behaviour of players and they should (?) be corrected to better depict reality. On the other side, I don't want to castrate my enemies too much because finally I find right that they are rewarded for outperforming Japanese posture toward ASW and convoys in general.
So I would like to have some limit to Japanese, but nothing special. Regarding the USN subs, my idea is that they should be better but still far below historic performance, provided the Japanese player is committed to establish an effective ASW and convoy system.
That's why I will consider for example an HR regarding IJAAF in ASW missions: that alone should limit by a considerable amount the effectiveness of Japanese ASW and, on the other side, present a tough cost-opportunity, since we all know that IJAAF planes and pilotes are precious.

Same goes with limiting PB conversions. The basic idea is to create a cost-opportunity for the Japanese player, who will be pressed to find escorts for all his convoys instead of having huge numbers of them available early on.

You may add the "no US faulty torpedo" in the options and then I think USN subs will be a bigger threat.

All this without altering a single thing in the game, therefore enabling literally everyone to apply these HR with no need at all to do modifications to scenarios or even modding.

USN subs should be more effective than usual but without being on par to their historic counterparts if the Japanese player is dedicated enough to ASW.

Just my opinion on the matter, that's all

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RE: stock torp dud rate - 12/10/2019 8:57:50 PM

engineer

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Torpex started being used in late 1942 and boosted the explosive power of the warhead by about 50% over TNT. All of the stock effects for mines and torpedoes presume TNT for the USN. Visit Navweapons and they give a comprehensive run down on when the various torpedoes and mines switched to TPX for mod in a 50% increase in explosive power.

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Post #: 33

RE: stock torp dud rate - 12/13/2019 3:17:08 PM

Big B

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quote:

ORIGINAL: LargeSlowTarget

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

Hi, been away for a while and saw this.
in 2016 I undertook to evaluate the true effectiveness of the Mk14 torpedo (and Mk10) from a variety of sources.
I found quite a few articles on the subject, including documentation of the JANAC Report, which was done after the war and utilized the records of ALL nations involved in WW2 (especially Japan) to record the losses and causes of losses of all Japanese shipping during the war - a real gold mine; as well as reading the log books of all USN submarine patrols - concentrating only on 1941, 1942, & 1943.
With these resources I used MS.Excel to plot each submarine's patrol log, and verified the log against the JANAC report to get an accurate picture.

This proved to be an enormous task. I finished the S-Boats for 1941-1943, and got only part way through the Fleet Boats for that period, before deciding that to complete the Fleet Boat patrol records would take more time than I had at the time, but I plotted enough to get a good sample, figuring I would finish the task later on.

During this process I discovered this: https://dionysus.biz/torpedoaccuracy.html and contacted the author Paul Watson to get further help since he had done a great analasys on this very complicated subject. We stayed in touch for an extended time as I was going through Fleet Boat log books.

After reviewing and correlating all this data, I incorporated changes to the dud rate of the Mk14 and began testing with game results.
George Gillian worked with me to write a program that would help read all combat reports generated by the game, to capture ALL submarine attacks in the game, number of shots fired and results, to see what the game was producing - to compile an accuracy record for submarine attacks to compare against the real WW2 record.

Then I began to run an extended series of AI vs AI test games to see what was going on with the new dud rate I incorporated, and the same with dud rate off - to compare against.

Sadly, a while back those two computers died (some time after completion of research and testing) and I do not now have all that data, only one screenshot from April 2016 documenting progress results up to that time (seen below), and that was before I started saving everything in 'the cloud'.

The question was asked what happened in April 1942 to improve torpedo reliability? With all my notes gone - I cannot definitively say what I discovered, however it was a simple quick-fix incorporated...something along the lines of re-enforcing lock pins or some such - which was discovered quite early - long before the Lockwood test.
A word about the Lockwood test - it showed a 7 out of 10 breakage of the firing mechanism for the pistol - due to being constructed for a slower (and therefore lower impact force) torpedo - True.
But also found was that this only effected 90 degree full impact hits - the further the torpedo struck off a 90 degree right angle - performance functionality dramatically improved. So, if a target ship discovered a torpedo track heading for it - any evasive maneuver would increase the effectiveness of a successful hit...only a 'blind sitting duck' would be "relatively" safer.
Furthermore, the only 'live warhead' test conducted by the Navy early in the war (1942), after reports of duds came flooding in, was at Hawaii against an underwater cliff, 2 out of 3 functioned perfectly, so this has to be taken into account with the Lockwood test.
We also assume that the magnetic exploder didn't work at all - often enough they did work...at least as often as they prematurely exploded. the test rate was about 50/50.

All of this combined shows the deficiency in the early performance of the Mk14, but it did still work enough to sink 158 (JANAC) Japanese ships in 1942, and better later on.
In the stock game profile this won't ever happen, and with the changes I incorporated - it still won't happen...but it performs a bit better than stock.

I would urge everyone to follow the link above to Paul Watson's article to get a more detailed understanding.

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< Message edited by Big B -- 12/13/2019 4:17:39 PM >

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RE: stock torp dud rate - 12/14/2019 3:14:12 AM

LargeSlowTarget

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Thanks Big B for answering. I understand that your adjustments have been made to help Allied AI-driven submarines to perform closer to historic results?

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RE: stock torp dud rate - 12/14/2019 4:25:06 PM

Big B

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It affects Mk14 Torpedo armed subs in 1942-1943.
Their chance of a dud is reduced compared to stock (though still high), AI or human player makes no difference... the game engine determines the results of all combat in all circumstances.
The only input the human can have on results would be their submarine deployment choices....possibly getting more boats into possible combat - but the human has no effect on how combat works out (die rolls so to say) - as we all know.

B

quote:

ORIGINAL: LargeSlowTarget

Thanks Big B for answering. I understand that your adjustments have been made to help Allied AI-driven submarines to perform closer to historic results?

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RE: stock torp dud rate - 12/14/2019 4:29:57 PM

Anachro

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@BigB If you happen to have those 2 computers sitting in the garage, you can easily recover the HDDs, convert them to externals, and recover your lost data. I've done this many times before with old, dead PCs.

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RE: stock torp dud rate - 12/14/2019 4:37:48 PM

Big B

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The problem is - one is gone, and the other had the hard drive reformatted.

quote:

ORIGINAL: Anachro

@BigB If you happen to have those 2 computers sitting in the garage, you can easily recover the HDDs, convert them to externals, and recover your lost data. I've done this many times before with old, dead PCs.

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RE: stock torp dud rate - 12/15/2019 9:29:57 PM

Big B

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Hello all. I wanted to put a question out to the Forum members with a mathematical and physics mind, regarding the Mk14 Torpedo, which has long tantalized me, specifically about the Admiral Lockwood Test.

Apparently in August 1943, tests were carried out by COMSUBPAC's gunnery and torpedo officer, Art Taylor, who used a crane to drop warheads filled with sand instead of high explosive from a height of 90 feet (27 m) (the height was chosen so the velocity at impact would match the torpedo's running speed of 46 knots). In these drop tests, 70% of the exploders failed to detonate when they hit the target at 90 degrees. A quick fix was to encourage "glancing" shots (which cut the number of duds in half).

This cuts to the meat of my quandary regarding the Lockwood (Taylor) test.

A long time ago, while researching exactly how armor penetration works (specifically at that time - the subject was WW2 AFV's), after contacting the physics Dept of Cal State Fullerton, and getting guidance on references, and contacting the US Army Historical Records Dept., as well as my local Congressman - I found some interesting phenomena.

Penetration is not simple...a shell of a given diameter, hardness, and weight must first have enough energy to overcome: the hardness of the target armor, then the thickness of the target armor, then the weight of the plate being struck, then - depending on the quality of the armor itself - the jointing or attachment of that plate to the frame or body of the vehicle as a whole, then last comes the entire density or if well fastened - the weight of the target vehicle as a whole. The projectile must overwhelm all of these combined criteria in toto to achieve penetration of the target...obviously - not all criteria are of equal weight in the calculation, but ll factor in. (not counting in incident of impact - angle of obliquity of a shell strike).
To sum up - a plate of a given thickness does not provide the same protection to an AFV in all circumstances...because of all the above factors combining at once.
Thus in WW2 terms, for example, an APCBC shell hitting the 80mm front hull plate of a PZKW IV AufsJ at 25 tons, does not offer the same challenge as penetrating the 80mm side armor of a 57 ton PZKW VI AufsE Tiger. All things being equal(?) the heavy Tiger will be harder to punch through, given the greater target mass/density to overcome.....by exactly what magnitude? - I don't know...but there's something to it.

What does that have to do with the Lockwood test? I'm coming to that...

When Taylor dropped those Mk14 torpedoes on a concrete platform at 90 feet to match the speed of a 46 knot torpedo, he got the same speed, and required deformation of the guides for (for lack of a better term) the firing pin to shoot the pistol to detonate the torpedo.

What my mind wonders is - Free Fall also introduces acceleration forces. A torpedo bullying it's way through dense ocean water - to my mind - will not have acceleration forces rapidly building up. Also, water provides buoyancy resistance above, below, and in path. It must support the weight of the 3,280 pound torpedo.
When a torpedo hits a target in mid-ocean, it's mass of weight is supported - relieving the kinetic forces of it's mass somewhat upon impact.
Put another way - the kinetic force of all 3,280 pounds is not in free-fall acceleration on the single point of it's detonator.

Also, consider that the 90 foot free-fall test was onto a concrete pad on earth. Ships, sail through water. Not only does water give, adding a bit of elasticity, but steel plates backed by air - also give to forces, - giving elasticity...any photo of any long service warship shows the skeleton of the ribs behind the deformed steel skin. Concrete on dirt/earth doesn't do that.

Therefore, I question the validity of a 90 foot drop free-fall test on it's firing pin? It seems to me one would expect forces exerted on that small firing pin to be (far) greater in such a test than would actually be expected in a real torpedo run through the ocean?
Extrapolating this hypothesis - was the Lockwood test actually creating far more failures than should be expected in real world circumstances?

The data Paul Watson extracted from actual war patrol records of hits and sinkings seems to support my quandary - given that his actual hit percentages correlated from 1942 (the highest recorded by the US Navy) - would suggest this.

This is my open question to our Forum members who understand the topic... I'm unsure.
Hey - maybe I'm all wet....I don't know.

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RE: stock torp dud rate - 12/16/2019 12:39:13 AM

Chickenboy

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My recollection of the physics comparables here BigB is that acceleration doesn't matter at the point of impact with the side of the ship or the ground in Lockwood's test. Acceleration in either instance will quickly go to negative numbers and then very quickly to zero as the torpedo head decelerates / deforms upon impact. There is no 'force of acceleration' functional difference that I can see at the point of impact as that point of impact in either case will result in the stoppage of the torpedo. Provided that the calculated forces are comparables.

The bigger question is whether the force upon the firing pin from a 90ft. drop is equivalent to a torpedo running at full speed and hitting a non-deforming ship side. My gut says that it's not the same and that the crane-dropped torpedo would have more force on the firing pin than the same one in the ocean/ship interface. But this can be calculated and the height of the drop decreased if the 'numbers' don't work out similarly. In other words, I agree. The Lockwood test seemed more severe than real-life forces.

But without redoing Lockwood's test from varying heights we are left with the field results that-marginally-worked. By redoing the firing pins and strengthening them, the torpedoes *did* perform better. So Lockwood was definitely on to something, but his test may have been an extreme one to prove a point.

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RE: stock torp dud rate - 12/16/2019 1:00:26 AM

Zorch

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This may seem like a stupid question, but why didn't the US just copy other country's firing pins?

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RE: stock torp dud rate - 12/16/2019 1:01:20 AM

Chickenboy

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quote:

ORIGINAL: Zorch

This may seem like a stupid question, but why didn't the US just copy other country's firing pins?

Actually, Zilch, that's a damn good question.

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RE: stock torp dud rate - 12/16/2019 1:08:32 AM

Zorch

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quote:

ORIGINAL: Chickenboy

quote:

ORIGINAL: Zorch

This may seem like a stupid question, but why didn't the US just copy other country's firing pins?

Actually, Zilch, that's a damn good question.

Or they could have kept (or slightly improved) the firing pins from the Mark 10...but that would have been too easy.

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RE: stock torp dud rate - 12/16/2019 4:18:26 AM

BBfanboy

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quote:

ORIGINAL: Zorch

This may seem like a stupid question, but why didn't the US just copy other country's firing pins?

The US copied virtually the entire German electric torpedo ... once they got their hands on one.

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RE: stock torp dud rate - 12/16/2019 9:19:56 AM

Buckrock

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quote:

ORIGINAL: Big B
Therefore, I question the validity of a 90 foot drop free-fall test on it's firing pin? It seems to me one would expect forces exerted on that small firing pin to be (far) greater in such a test than would actually be expected in a real torpedo run through the ocean?
Extrapolating this hypothesis - was the Lockwood test actually creating far more failures than should be expected in real world circumstances?

The data Paul Watson extracted from actual war patrol records of hits and sinkings seems to support my quandary - given that his actual hit percentages correlated from 1942 (the highest recorded by the US Navy) - would suggest this.

This is my open question to our Forum members who understand the topic... I'm unsure.
Hey - maybe I'm all wet....I don't know.

It's been a while since high school physics, so I won't test my memory but I'd be surprised if the group that organized the drop tests lacked sufficient engineering knowledge to determine the proper conditions. And the test results led the "experts" at the Bureau of Ordnance to finally acknowledge the contact exploder needed redesigning, which was no mean feat.

It almost sounds like you're wondering whether the efforts to fix the Mark XIV's problems may have led to the torpedo becoming less effective than it was in the first year of the war. Is that a correct reading of your original post?

I read Watson's article. I didn't necessarily agree with the specific hit rates his modelling suggested but there appears no doubt the yearly comparisons between total torpedoes fired vs total merchants sunk do point to 1942 as the most efficient year. Unfortunately Watson appears to be only able to guess at why this may have happened but his suggestion seems valid that the natural learning curve of experience was being defeated by constant expansion of the submarine force through most of the war. In regards to that, it could also be said 1942 had an additional advantage over later years as it was likely the last time that the majority of fleet subs going out on patrol would be ones manned by highly trained pre-war crews. They may have gone to war with less than suitable doctrine but their prior extensive training and technical skillset should (in theory) have given them a jump-start in adapting to wartime conditons.

Personally, I think it's also worth noting that 1942 was the only year when the Mark XIV was being widely used all year with the Mark VI's magnetic influence device enabled. For all its faults, that component of the Mark VI just might have been making more of a contribution than realised to the overall 1942 score, particularly in the latitudes well north of the equator such the waters off Japan where sizable numbers of ships were actually being sunk despite the various issues of the torpedo.

Can't blame the crews for wanting the Mark VI's influence device gone though. Premature detonations and torpedoes circling back with active magnetic exploders don't make for a fun patrol.

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