RE: ASW Stuff (Full Version)

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vettim89 -> RE: ASW Stuff (7/7/2011 10:28:24 PM)


quote:

ORIGINAL: JWE


quote:

ORIGINAL: vettim89
So perhaps its not just about weapons moints and how they are displayed in the DB. Maybe ASW rating, which of course is related to the number of weapons mounts, is just as big a factor. If true then the "E" class patrol craft will still have the obnoxious ASW of 12 no matter how the mounts are grouped. Just throwing that out there for consideration

nooo ... ASW rating has no impact. It is nothing but a WeapNum summation shown on the ship screen that people can use to roughly judge who's better then who. There are 3 different things that happen; in sequence, but with some overlap.

1) Acquisition - You need a good Detect value to find and hold a sub for prosecution. Leader and crew exp values are of primary importance.
2) Prosecution - Done on an individual ship-by-ship basis. Crew exp values are of primary importance.
...2a) How many weapons (i.e., slots) will engage? Crew exp values are of primary importance.
...2b) How many passes (i.e., attacks) will the ship make? Crew exp values are of primary importance.
...2c) Before each pass, will the ship acquire/reacquire the sub? Crew exp values are of primary importance.
3) Destruction - Done on an individual WeapSlot-by-slot basis. WeapNum is of primary importance.
...this is the only place in the wide, wide, world of sports, where WeapNum of a slot is important. This is the % chance to hit part. All the rest is just % chance to acquire and % chance to shoot.

So all of your 'messages' relate to item ...2c), except the last one which indicates 'close but no cigar' under item 3). Before you drop, the sub can evade. You can lose contact while moving into position to drop. You might just be too far away to effectively prosecute. None of these things have anything to do with how many DC launchers (or slots) you gots. That happens in part 3). And that's where the math comes into play.

This is NOT THE ALGORITHM. It is an UTTER SIMPLIFICATION, but it might give you some idea of what's involved. A slot might have Num of 2, 3, 4. Think of 2^Num and you get 4, 8, 16. Think of that as a % chance to hit with that slot. Now make a slot with Num of 12 or 16 (the original Es). 2^Num is 4096 or 65536. A little bigger than 16, yes? So if an original E could acquire, it could prosecute (those 12-16 launchers were in 1 slot). If it could shoot it WOULD KILL. That was the booger. And a right wet and green one it was, too.

I really hope this makes sense to ya'll. Ciao. John


John,

That does make sense. However, when I ran my naked ASW tests last year I found that ASW value does play a big role in a TF's ability to detect a sub that starts the turn with a detection level of 0. I ran a test bed scenario where all other factors were the same (same ships, same crew exp, same environment). What I changed was the ASW value. I stared with 2 then went to 3 then 6. With each succeeding increase I saw a higher number of detections then prosecutions by the ASW TF. The test had the ASW TF's deliberately passing over the top of undetected subs. So while the ASW value does not have an effect on the combat once it starts, it does seem to have an affect on if there will be combat.



witpqs -> RE: ASW Stuff (7/7/2011 10:33:37 PM)


quote:

ORIGINAL: JWE

...2a) How many weapons (i.e., slots) will engage? Crew exp values are of primary importance.



This one is a very, very nice detail. I shortly ago finished reading Turning The Tide, which focused on a few convoys at that point in the Battle of the Atlantic during which things went from bad to good for the Allies. There were many instances cited of an escort dropping only one (1) depth charge!

I know that earlier someone posted that such was never done and only patterns used. While that isn't strictly true, the post wasn't totally off either. What I mean is that the "1" depth charge attacks were used when they did not have a very good contact on the u-boat, with the intention to keep it down and hiding instead of trying to maneuver back into attack position. They used full patterns when they had decent contact and thought they could damage or sink the u-boat. They also fired/dropped between 1 and "full" (which varied by ship of course), just depending on the captain's judgement.

The number of depth charges on board and how much longer the convoy had to run versus when they could make port to rearm were key considerations.

So, this line item about how many weapons will engage is a quite nice addition to the realism.



JWE -> RE: ASW Stuff (7/7/2011 10:36:46 PM)


quote:

ORIGINAL: oldman45
Since crew exp plays such a large role, how then is the best way to get the US "escort" crews up to speed so that in 1943/44 they do a great job of keeping the subs at bay? In my game I try to always use the same group of "escorts" doing nothing but ASW hunting but I do not see a lot of change in exp.

As vettim says, "Just steaming will raise exp but it has a cap." Ok, true. But just 'hunting' won't do either. One must kill in order to know how to do so better.

Local Yokel has an excellent IJN "training" approach that might be of benefit to other nationalities. There's some code things that happen annually, from '42 on, that deal with some of this stuff, but specific and directed training, a la LY's method, is a good thing all around.



Local Yokel -> RE: ASW Stuff (7/8/2011 12:57:27 AM)

quote:

ORIGINAL: JWE

This is NOT THE ALGORITHM. It is an UTTER SIMPLIFICATION, but it might give you some idea of what's involved. A slot might have Num of 2, 3, 4. Think of 2^Num and you get 4, 8, 16. Think of that as a % chance to hit with that slot. Now make a slot with Num of 12 or 16 (the original Es). 2^Num is 4096 or 65536. A little bigger than 16, yes? So if an original E could acquire, it could prosecute (those 12-16 launchers were in 1 slot). If it could shoot it WOULD KILL. That was the booger. And a right wet and green one it was, too.


That is a lucid explanation of the consequences of having a large number of 'tubes' in a single weapon slot. It makes it entirely comprehensible that an IJN Escort that fires a 12- or 14-tube weapon slot is more or less assured of a kill.

It seems to me that it also makes it clear that you have little to fear by restoring to those E's their full complement of 12 or 16 side throwers provided you break that complement down into multiple slots. Adopting JWE's example, if a C- or D-gata kaibokan's 12 throwers are broken down into four groups of 3 (2 on each side) as suggested in my post #13 then each slot (if it fires at all - JWE's 2a) has a 2^3 % chance of a hit = 8%.

Compare and contrast with the Tacoma/Colony class DE's with their single bank of 8 centreline Y-guns (this is actually wrong – the Tacomas mounted 4 K-guns on each side, so the weapons fit should be reconfigured for this reason alone). If this 8-tube slot gets to fire then it's 2^8 % chance of a hit = 512% - bye,bye I-boat. This is why I think this class requires further attention.

Treespider was absolutely on the mark: I was concerned that halving the number of throwers on the E’s might have been prompted by a mistaken perception of what was required for historical accuracy. Not only might these ships' apparently overpowered performance have been the product of game circumstances (e.g. better air search raising DL's, better tactics by Player 2), but also our perception of history might be adrift. Not too long ago, thanks to Fuchida Mitsuo, conventional wisdom had it that at Midway Enterprise and Yorktown’s SBDs caught KdB with flight decks crammed with strike aircraft at the point of launch. Now we have good reason to think otherwise – our perception of history was fundamentally flawed. The same might have been the case as regards our perception of Japanese ASW ships' capabilities.

In the event, I think JWE's clarification shows that the only problem with the supposedly overpowered E's is the excessive concentration of tubes in a single slot, and the good news is that it seems that these ships can still carry their full complement of throwers without becoming excessively powerful by parcelling those throwers out into multiple slots. In other words the standard method of modelling a ship's armament still holds good.

On training and experience levels, I strongly recommend people to take a look at section 3.3.1.1 of the Editor manual, which is highly instructive. What this shows is that in 1941-42 non-British Allied crews arrive at 80% of the base experience level (Note 1), and from 1943 onwards at base level + random 0-10. Japanese crews enjoy an experience advantage in the first two years, but thereafter the difference between opposing crews' initial experience is minimal. Note that:

a) Allied DEs' base experience level is 50. For E-class ships it is unspecified but appears to be 40.
b) The Japanese are subject to a significant experience disadvantage in ASW due to their negative modifier and the Allied crews' positive modifier. Getting decent ASW performance out of Japanese crews will be no easy matter.

<edit> Note 1: plus random 0-10 </edit>



oldman45 -> RE: ASW Stuff (7/8/2011 1:55:42 AM)

Thanks John, Thanks LY.



el cid again -> RE: ASW Stuff (7/8/2011 4:28:03 AM)

At least we are getting some information about how things work in code. It probably isn't the way things ought to work,
but unless someone decides to change it, it is what we have. The problem here is that other weapons tend to shoot only
if there is a target out there to shoot at - on their bearing. ASW weapons tend to shoot in patterns, somewhat blindly,
to make up for the lack of precision of target location (the target moves during the fall of shot, as it were, and there is
usually time between detection and reaching the drop point as well - during which the target may maneuver - and it almost
certainly changes position even if not course). So ideally we should consume shot for all the weapons, even if only one
is able to "bear" - as it were. That still sounds to me like you want to model the data for a single weapon - possibly two
if there are ahead throwers (these bear forward, DCT and DC from racks "bear" aft) - and the number of shots is simply
the number of patterns - not the number of DC or tubes etc.

The way to have your cake and eat it too - get the ammo consumption of the entire pattern and the effect of only one round
able to hit the target per "shot" - is to use statistics. The chance a pattern hits a submarine is well worked out in theory -
and the difference between that and practice is well understood as well because we have good statistics. What we do not have
(I think) but might be able to derive by testing is the % of a "shot" hitting in game terms. The % is almost an overstatement -
in 200 attacks (mainly by DC and Squid) in the Falklands, 100% missed - by the NATO specialists in ASW! [To be fair - only
a couple of the attacks had a real target - probably a lot of whales were attacked as well] But if you want to say that a good value
is in the single digit % range - that is reasonable and more fun than a fraction of a % - then you just make the value of your
weapon be n - and a ship with a larger pattern gets 2n or 3n - etc.

If a Tacoma has 4 K guns on one side, and one wanted to model that with centerline Y guns, surly one would use 4 (each throwing 2) to the
one a K gun throws. What bothers me is that a submarine is not really attacked the way a surface target is - on the bearing of the weapon.
It literally moves into the weapon that hits it - whatever its bearing was when the weapon was dropped. The attacking vessel essentially
must close to zero range and then the attack occurs astern in the age before ahead throwers. Except for Squid, one ought not think of firing
in the direction of a target off the side of the ship. And in order to hit, Squid tries to surround the "datum point" with DC - so that whatever the
target does - it is likely to be close to one of them. It just doesn't have to pass over the datum point before it drops like a classical ASW ship did.
The point of the pattern is to get explosives in a circle (or oval really) such that the target is likely to be near one or between two - assuming
one had actually solved the fire control problem with good data (which is rare). But it is so statistical that it can be abstractly modeled fairly well.



JWE -> RE: ASW Stuff (7/8/2011 1:30:22 PM)


quote:

ORIGINAL: Local Yokel
It seems to me that it also makes it clear that you have little to fear by restoring to those E's their full complement of 12 or 16 side throwers provided you break that complement down into multiple slots. Adopting JWE's example, if a C- or D-gata kaibokan's 12 throwers are broken down into four groups of 3 (2 on each side) as suggested in my post #13 then each slot (if it fires at all - JWE's 2a) has a 2^3 % chance of a hit = 8%.

Two things, John. Please don't make the mistake of thinking that's how the code works. As I tried to make real clear, it doesn't signify. It was a quick, simple, and easily understandable way of showing magnitudes. It might serve as a good broad brush rule of thumb, but it has no mathematical applicability to the algorithm.

The other is that the probabilities have depth as well as width. 4 groups of 3 are definitely not as powerful as 1 group of 12, but again, the total of the sequential hit probabilities of dropping 3, 3, 3, 3 are way more than twice (almost an order of magnitude) the the total of the sequential hit probabilities of only dropping 3, 3 (but at least it isn't 4000 times [;)]). Not to say you shouldn't try it your way, but you may find you have only gotten part way there in getting those pesky Es into line. Something to keep your eye on, anyway. Give it a shot, let us know how it works out.



JWE -> RE: ASW Stuff (7/8/2011 3:19:37 PM)

Btw, Mr Palmer, we are vetting "every" combatant ship class and adjusting "everything" to the model: Sum[Num x Ammo] = (Irl Ammo)/2

While we are at it, we are getting the launcher distributions (# of slots, Num per slot) for everybody down pretty pat. Have good data on who did what to whom and when, so we'll tweak the Tacoma/Colony class while this is going on. The project does not seem to require any major adjustments, just a lotta little dinky tweaks here and there. Nothing especially noteworthy, except for ammo, but what's good for the IJN goose is certainly good for the Allied Gander.

While we are slicing and dicing the class slots, thought we might get the DD radars under better control, too.

Coming soon to a theater near you.



Buck Beach -> RE: ASW Stuff (7/8/2011 4:23:18 PM)


quote:

ORIGINAL: JWE

Btw, Mr Palmer, we are vetting "every" combatant ship class and adjusting "everything" to the model: Sum[Num x Ammo] = (Irl Ammo)/2

While we are at it, we are getting the launcher distributions (# of slots, Num per slot) for everybody down pretty pat. Have good data on who did what to whom and when, so we'll tweak the Tacoma/Colony class while this is going on. The project does not seem to require any major adjustments, just a lotta little dinky tweaks here and there. Nothing especially noteworthy, except for ammo, but what's good for the IJN goose is certainly good for the Allied Gander.

While we are slicing and dicing the class slots, thought we might get the DD radars under better control, too.

Coming soon to a theater near you.


Probably not something appropriate for this thread but something to think about if your going to do some tinkering away. I have always thought there should be some way to account for those naval guns connected to a "fire control system". Maybe an accuracy penalty (separate devices) for the merchant ship's guns or other ships accordingly not having such systems.

Not smart enough to figure it out beyond the thought.

Buck



Local Yokel -> RE: ASW Stuff (7/8/2011 4:29:32 PM)

John, you are right to chide me for over-simplifying. And I take your point about the rate of increase in sequential hit probabilities. Nevertheless, the larger the number of weapons an ASW ship can put in the water on a single pass, surely the more effective its attack is likely to be?

Elsewhere I've touched upon IJN doctrine being the laying down of the biggest possible pattern on a CertSub, and the USNTMJ's report’s description of a 19-charge pattern for a kaibokan. It is with this in mind that I should like to find a way of imparting to the IJN E-class ships the benefit of their large number of throwers, provided this can be reconciled with the need not confer Wunderwaffe capability upon them.

In the case of 6-per-side launcher banks we don't necessarily have to split them into 2 banks of 3, and presumably a reversal of that arrangement to 3 banks of 2 per side will further attenuate an excessive increase in sequential hit probability whilst preserving the full number of launchers. Doing this would require the use of 4 extra slots, but even in the worst case of the Ukurus there are 8 spare slots available (the Ukurus are the most difficult to model in the conventional way, given their fit of 16 Type 3 launchers).

If some further toning down of the late kaibokan classes is required, then what about the capabilities of the depth charge devices themselves? In this thread you explained that a depth charge device's Range value was a reflection of the maximum depth setting of its pistol. In stock scenario 1 Range values for Japanese d/c's correspond closely with the max. depth settings given in Campbell (T-95: 197ft (game:164); T-95 Mod 2: 295ft and T-2: 476ft), which seem to bear this out. However, in Big Babes these values have been changed to T-95: 175; T-95 Mod 2: 275; T-2: 357 and I must say that this is a bit of a puzzle, particularly since the 357 value for the Type-2 doesn't seem to correspond to any of the pistol depth settings given in Campbell. Does this mean that the depth charge device's Range value is actually referring to something other than just depth?

What occurs to me is that if Range does represent max. depth pistol setting, then we have a means for limiting the depth at which the can will explode, below which the submarine may successfully evade. For example we could have a 'Type 2 d/c Shallow' device having all the characteristics of the standard Type 2 but with a Range of, say, 98 for the 30m pistol setting rather than the standard Range of 357 (or should it be 476?) If you make a proportion of the multiple slots on the kaibokan fire this shallow setting charge, you have enhanced the likelihood that the attacked submarine will have evaded to a depth where it is safe from such a weapon's attack. This might be a way of simulating the shallow-set charges fired in a large pattern – see the pattern diagram in the USNTMJ report - and should further tone down the potency of the kaibokan if that is necessary.

I'll post separately on the subject of radars as this was something I took a look at in the kaibokan TROMS. Will just say here that I am delighted to hear that you are looking at launcher/ ammunition values across the board.



Shark7 -> RE: ASW Stuff (7/8/2011 4:31:27 PM)


quote:

ORIGINAL: Buck Beach


quote:

ORIGINAL: JWE

Btw, Mr Palmer, we are vetting "every" combatant ship class and adjusting "everything" to the model: Sum[Num x Ammo] = (Irl Ammo)/2

While we are at it, we are getting the launcher distributions (# of slots, Num per slot) for everybody down pretty pat. Have good data on who did what to whom and when, so we'll tweak the Tacoma/Colony class while this is going on. The project does not seem to require any major adjustments, just a lotta little dinky tweaks here and there. Nothing especially noteworthy, except for ammo, but what's good for the IJN goose is certainly good for the Allied Gander.

While we are slicing and dicing the class slots, thought we might get the DD radars under better control, too.

Coming soon to a theater near you.


Probably not something appropriate for this thread but something to think about if your going to do some tinkering away. I have always thought there should be some way to account for those naval guns connected to a "fire control system". Maybe an accuracy penalty (separate devices) for the merchant ship's guns or other ships accordingly not having such systems.

Not smart enough to figure it out beyond the thought.

Buck


Perhaps reducing accuracy by 25-50%? Just a thought. [;)]



JWE -> RE: ASW Stuff (7/8/2011 5:46:17 PM)

Babes has already tweaked the capabilities of depth charges vs diving depth of subs. This one is wrapped up very tightly with the algorithm, so I can’t say much about it. But, there is a bit of fuzzy math going on between the bottom of the drop depth of a DC and the diving depth of a sub, so it is “rational” to set the “drop depth” of a Type-2 at 375 feet, and the “diving depth” of a Balao or Tench at 410 feet, for example. Similarly, it is “rational” to set the “drop depth” of T-95 Mod 2s at 275 feet, while Gars, Tambors, Gatos can dive to 300 to 330 feet. That’s all I can say about it. Looked for hints to give, but just couldn’t find any that wouldn’t screw the pooch.



oldman45 -> RE: ASW Stuff (7/8/2011 6:40:46 PM)

After reading this page, I want to buy you all a drink ;)



Bradley7735 -> RE: ASW Stuff (7/8/2011 7:19:40 PM)


quote:

ORIGINAL: oldman45

After reading this page, I want to buy you all a drink ;)


+1. I'm thankful and impressed with the folks (mostly unknown to me I'm sure) who keep ironing out the little bumps in the game. And, I do stress 'little.'



mike scholl 1 -> RE: ASW Stuff (7/9/2011 1:41:45 AM)


quote:

ORIGINAL: Local Yokel

John, you are right to chide me for over-simplifying. And I take your point about the rate of increase in sequential hit probabilities. Nevertheless, the larger the number of weapons an ASW ship can put in the water on a single pass, surely the more effective its attack is likely to be?

Elsewhere I've touched upon IJN doctrine being the laying down of the biggest possible pattern on a CertSub, and the USNTMJ's report’s description of a 19-charge pattern for a kaibokan. It is with this in mind that I should like to find a way of imparting to the IJN E-class ships the benefit of their large number of throwers, provided this can be reconciled with the need not confer Wunderwaffe capability upon them.



Reality check, "Yokel". In 44 months of war, Japanese surface vessels sank 21 US Subs (confirmed). Four more were sunk by "unknown" sources. Even if you give two of these "unknowns" to Japanese surface forces, that still makes less than one sinking every two months by ALL Japanese surface vessels. The US DE England sank 6 Japanese subs in TWO WEEKS!

ASW Warfare is not about the number of depth charges you can throw over the side..., it's about finding and fixing the target sub and the accuracy with which the ASW weapons can be delivered on the target. Without the electronics and sound equipment to "fix" a target, the Japanese had to use a "heave and hope" approach..., and history shows that it was not a great success.



Big B -> RE: ASW Stuff (7/9/2011 2:08:56 AM)

Hi all, interesting thread, but I have a sincere but innocent question on Japanese Escorts: What source is there for determining how many DC Throwers they carried and where?
I have Conway's All the World's Fighting Ships 1922-1946, and Jane's Fighting Ships WWII. Neither of those sources carry that info. Conway's only addresses the total number of DC's carried for Japanese DD's & Escorts (it does state numbers of DC racks for IJN DD's, and the locations and numbers of DC Racks and K-Gun Mounts for USN DD's & DE's ...but nothing on IJN Escorts)?

So I am curious as to the source for the details on IJN Escorts? Inquiring minds would like to know?

EDIT: OK - it looks like Online Sources will give you the Info [;)]





Big B -> RE: ASW Stuff (7/9/2011 2:25:40 AM)

KAIBOKAN C and D
October 8, 2010 0 Comments
Link

It does appear they may be overpowered in the game, historical win/loss rate vs submarines shown below:
13 Escorts sunk by Submarines vs 4 Submarines sunk by these same Escorts:
Ships lost

CD-1, commissioned on February 19, 1944. CD-1 was sunk by B-25 bombers on April 6, 1945.

CD-3, commissioned on February 29, 1944. CD-3 was sunk by TF 38 carrier aircraft on January 9, 1945 at 27-10N, 121-45E.

CD-5, commissioned on March 19, 1944. CD-5 was sunk by carrier aircraft on September 9, being set afire and later blowing up and sinking at 15-30N, 119-50E.

CD-7, commissioned on March 10, 1944. CD-7 was torpedoed and sunk by USS Ray on November 14, 1944 at 17-46N, 117-57E.

CD-9, commissioned on March 28, 1944. CD-9 was torpedoed and sunk by USS Gato on January 12, 1945 at 32-43N, 125-37E.

CD-11, commissioned on April 5, 1944. CD-11 was damaged and had to be beached by B-25 bombers on November 10, 1944 at 10-51N, 124-32E.

CD-13, commissioned on April 26, 1944. CD-13 was torpedoed and sunk by USS Torsk on August 14, 1945, the day before the end of the war.

CD-15, commissioned on May 1, 1944. CD-15 was torpedoed and sunk by USS Raton on June 6, 1944.

CD-17, commissioned on May 7, 1944. CD-17 was torpedoed and damaged by USS Tilefish on July 18, 1944. CD-17 was sunk by carrier aircraft on January 12, 1945.

CD-19, commissioned on May 20, 1944. CD-19 was sunk by TF 38 carrier aircraft on January 12, 1945.

CD-21, commissioned on August 18, 1944. CD-21 was torpedoed and sunk by USS Seahorse on October 6, 1944.

CD-23, commissioned on October 29, 1944. CD-23 was sunk by carrier aircraft on January 12, 1945.

CD-25, commissioned on July 30, 1944. CD-25 was torpedoed and sunk by USS Springer on October 6, 1944.

CD-31, commissioned on October 13, 1944. CD-31 was torpedoed and sunk by USS Tirante on April 14, 1945.

CD-33, commissioned on October 13, 1944. CD-33 was sunk by carrier aircraft on March 28, 1945.

CD-35, commissioned on November 21, 1944. CD-35 was sunk by carrier aircraft on January 12, 1945.

CD-39, commissioned on November 9, 1944. CD-35 was sunk by B-25 "Mitchells" on August 7, 1945, the day the atomic bomb was dropped on Hiroshima.

CD-41, commissioned on November 26, 1944. CD-41 was torpedoed and sunk by USS Sea Owl on July 9, 1945.

CD-43, commissioned on September 10, 1944. CD-43 was sunk by carrier aircraft on January 12, 1945.

CD-47, commissioned on November 2, 1944. CD-47 was damaged by aircraft on three occasions, on January 29, February 15, and July 30, 1945. She was torpedoed and sunk by USS Torsk on August 14, 1945, the day before the end of the war.

CD-51, commissioned on October 29, 1944. She was sunk by TF 38 aircraft on January 12, 1945.

CD-53, completed on November 28, 1944. On February 7, 1945 She was torpedoed and sunk by USS Bergall.

CD-65, completed on February 13, 1945. She was sunk on July 14, 1945 by TF 38 carrier aircraft.

CD-69, completed on December 20, 1944. She was sunk on March 16, 1945 by B-25s.

CD-73, completed on April 5, 1945. On April 16, 1945, just eleven days after completion, she was torpedoed and sunk by USS Sunfish.

CD-75 , completed on April 12, 1945. She survived the war, but was torpedoed and damaged by Soviet submarine L12 on August 22, 1945. She was scuttled the next day.

CD-213, completed on February 12, 1945. On August 18, 1945, after the war ended, she sank after striking a mine.

CD-219, completed on January 25, 1945. She was sunk by TF 38 carrier aircraft on July 15, 1945 off Hakodate.

Successes

USS Growler was sunk on November 8, 1944 by CD-19 with Chiburi and destroyer Shigure.

USS Trigger was sunk on March 28, 1945 by CD-33 and CD-59 with Mikura.

USS Bonefish was sunk on June 19, 1945 by C Types CD-63, CD-75 and CD-207 with Okinawa and CD-158.

USS Salmon was rendered unfit for further service by damage from CD-33 and CD-29 with CD-22 on October 30, 1944.



The D Type class escort ships were a class of ships in the service of the Imperial Japanese Navy during World War II. The Japanese called them "D Type" coast defence ships, and they were the sixth class of Kaibokan (Kai = sea, ocean, Bo = defence, Kan = ship), a name used to denote a multi-purpose vessel.



The D Type, like the Ukuru-class and Mikura-class, were dedicated to the anti-aircraft and anti-submarine role.



inqistor -> RE: ASW Stuff (7/9/2011 8:28:00 AM)

I do not understand this "ammo" part.
During all this years, I have played WITP/AE, I have seen maybe 3 times, that ship ran out of DC ammo. And I do not think it is actually possible for not dedicated ASW TF.
So, this larger ammo allowance, will only kick in, when there will be more than, maybe 3 ASW attacks during mission. And all those attacks would have to be made by THE SAME ship. Quite rare occurrence.
Otherwise those ships will be actually WEAKER, because they will have LESS DC launchers.


I have checked my current GC game, and I see this number of spent DC ammo for ships on-map:
1 2 3 3 7
all launchers have full complement of 8 ammo


Same game, but month earlier save:
1 1 2 3+1(ship have launchers in 3 slots, 2 actually show ammo used) 2 4(the only ship, which spent all ammo) 2+5 7
Ships which shows only ONE number have all their DC launchers in ONE slot.

So, that indicates, that on-average ship uses 1-3 points of ammo per ASW attack. It also seems, that with several slots more than ONE is firing. So, as long as there is AT LEAST 3 ammo, behaviour of ships will be identical during ASW combat, and only difference will be number of launchers (or their mounting points).

This is not actual test, but it will be easy to actually check, if someone want to set scenario. Just some SS with non-working torpedoes, and some ASW groups. It will be easy to count used ammo after each attack.



el cid again -> RE: ASW Stuff: Air ASW (7/9/2011 8:46:08 AM)

I notice that in AE aircraft dedicated to hunting submarines do not carry ASW weapons.
They seem to rely on bombs. And to a lesser extent, on guns. Granted both are harmful
to submarines, still IRL all these aircraft ( and blimps ) carried DC - and sometimes no bombs
at all (a blimp typically only carried DC - and had a single nose .50 cal MG). In spite of how
UV and WITP worked, I was surprised to see this in AE.

Are these armament conventions correct in game terms? That is, does the air ASW model
ONLY permit a submarine to be attacked on the surface? In fact, submarines are much easier
to see from the air than from a ship - and the U-505 was captured because aircraft saw her
UNDERWATER and marked her position (by firing their MG at the position) so the ships knew
where to use their ASW weapons. Aircraft fitted with DC can drop - and often do not need
anything like the large patterns ships use - because they actually have a sense of where the
target is right now - where a ship is usually using old data - since it had to close the range
in order to attack.

Suppose a GAME aircraft were armed with DC - say a PBY. IF it spotted a submarine in code
terms, would the DC be "dropped" - and if so - would they do any harm to the target? Or are
DC hard coded as "ship weapons" - even specialized aircraft DC - and they will be ignored in a
submarine situation? IRL a DC need not hit a target to hurt it - and dropping near it is not a good
thing from the submarine point of view. But can we drop DC on submarines at all, even surfaced?
Can we treat them as a sort of "non AP bomb"?

IF this interpretation is correct, I propose to take a bomb device, give it a name as DC,
and value related to the way DC are rated (effect = weight in pounds I think, no penetration or perhaps
only a little) - so it looks like aircraft carry DC - and so the effects are not the same as for bomb hits
if they hit.




Local Yokel -> RE: ASW Stuff: Air ASW (7/9/2011 12:28:45 PM)

Ah "Scholl"… no, on second thoughts I'll not respond to your vacuous rehearsal of the obvious, as it will only encourage you to descend to the personal abuse in which you engaged in the "SLC = 15K VP" thread.

@Big B: You can find quite detailed information about all the kaibokan classes in the monograph by Hans Lengerer and Tomoko Rehm-Takahara that was published in three parts in Warship Nos.30-33, republished by Conway in 1984 in Warship Volume VIII. Additional information is available at the combinedfleet website.

Your casualty list omitted CD-112, a D-gata class member that deliberately intercepted a torpedo fired by SS-220 Barb at JNR ferry Soya Maru whilst on passage between Wakkanai and Odamari (Karafuto) on 18 July 1945.

The Yamato Museum at Kure has a large collection of naval photographs which includes an extensive selection of kaibokan shots.

On the subject of radar fitting dates, I went through all the kaibokan TROMS so far published on the combinedfleet site. Unfortunately these give no information at all about the 'Type 22' (strictly, 222 GÔ dentan) fitting dates, and very little about 'Type 13' (13 GÔ dentan) fit dates.

Specific mention is made of the following fittings of Type 13 sets:

CD-37 April 1945 (C-gata class)
Hachijo October 1943 (Shimushu class)
Oki June 1944 (Etorofu class)

Fitting dates are also given for Ikuna, Habushi and Imami, but these all appear to have been part of the vessels’ final fitting out when new.

Since they were all tucked away on Hokkaido-Sea of Okhotsk assignments I am doubtful as to whether, aside from Hachijo, any of the four Shimushus ever received a Type 13 set.

Pictures of C- and D-gata escorts carrying Type 13 antennae seem to be very uncommon, and I have seen only one picture of a Mikura so fitted. Lengerer observes that Type 13 sets were fitted to Mikuras 'as of autumn 1944'.

Most Ukurus seem to have been photographed with Type 13 antenna, and Ikuna's receipt of such a set in the same month as her completion – October 1944 – suggests that in the game the class should be eligible to receive them from this date.

Unfortunately I have been unable to put a date to most photographs I have seen, so it would be unwise to read too much into the photographic evidence.

As to the 222 GÔ dentan, Lengerer states that from about June 1943 the Etorofu class ships began to be fitted with a modified foremast topped by a platform to carry this pattern of surface search set. The combinedfleet site class summary page says that the class was re-armed with a sensor suite that included these sets 'by August 1943' – perhaps this, with Lengerer's remarks, suggest August 1943 as a more appropriate date for the availability of such an upgrade for the Etorofus than the game's February 1944 date.

The combinedfleet site summary says that Mikura class ships were fitted Type 22 sets in 1944. Lengerer says that the Mikuras were equipped with Type 22s 'when completed'. FWIW I have yet to see a photograph of a Mikura class ship was not equipped with a Type 22 set, so I am inclined to agree with Lengerer. This would imply their inclusion in the initial equipment for the class at slot 1302.

The Ukuru, C-gata and D-gata kaibokan are all fitted with Type 22 sets as built, so no difficulty there.

Incidentally, I think there is a case for introduction of an 'intermediate' class between the Mikuras and the Ukurus. This should consist of a Mikura A/S weapons fit on an Ukuru hull, and would reflect the fact that nine vessels built at Hitachi's Sakurajima yard were outfitted with the Mikuras' depth charge armament (2 X Type 94 Y-guns plus 2 stern rails), but allocated to the Ukuru class. The ships concerned were Hiburi, Daito, Shonan, Kume, Ikuna, Shisaka, Sakito, Mokuti and Habuto. In fact, taking this further, the Mikura class depth charge set-up in both stock and BigBabes appears to me to be completely wrong, and should be toned down as described for the Hitachi ships.



mike scholl 1 -> RE: ASW Stuff: Air ASW (7/9/2011 2:19:37 PM)


quote:

ORIGINAL: Local Yokel

Ah "Scholl"… no, on second thoughts I'll not respond to your vacuous rehearsal of the obvious, as it will only encourage you to descend to the personal abuse in which you engaged in the "SLC = 15K VP" thread.


RIGHT! Wouldn't want any nasty old "Historical Realities" poking holes in your fantasies. [8|][8|][8|][>:]



treespider -> RE: ASW Stuff: Air ASW (7/9/2011 2:31:13 PM)

quote:

ORIGINAL: mike scholl 1


quote:

ORIGINAL: Local Yokel

Ah "Scholl"… no, on second thoughts I'll not respond to your vacuous rehearsal of the obvious, as it will only encourage you to descend to the personal abuse in which you engaged in the "SLC = 15K VP" thread.


RIGHT! Wouldn't want any nasty old "Historical Realities" poking holes in your fantasies. [8|][8|][8|][>:]



To be fair Scholl the vast majority of the sinkings took place in 27 months (not 44) from 1/43 through 3/45.

Curious what the numbers would show if one were to compare ASW assets committed versus sinkings if one were to compare Pacific to Atlantic. for a similar time frame.


In other words the Germans lost circa 500 subs in 1943 and 44...but how many ASW assets were committed to the endeavor?

Versus the 40 some odd US subs lost to JApanese ASW assets.

I do not know the answer just curious what the ratios would be?



oldman45 -> RE: ASW Stuff: Air ASW (7/9/2011 4:39:23 PM)

Treespider - That would be an interesting bit of information to look at. Considering the Hunter-killer groups, LBA, and of course the convoy escorts themselves, I would be willing to go out on a limb and say the numbers would be two or three times higher than anything the Japanese mustered.

Inqistor - I went back and looked at some old saves and I found that my experienced ASW TF's would run out of DC's on 1 and sometimes 2 of the ships if they made multiple attacks which they usually did. This was in the late 1943 time period. Based on what has been written here, since the more experienced crews are acquiring the target more often they attack more often. I didn't bother to look at the Japanese sunk ship list to verify kills but these groups did infact claim more kills after their attacks.

Cid - I had the same thought the other day and have started working on a test to see if putting modified DC on a plane makes a difference. Not sure if it will work because of the game engine.



JWE -> RE: ASW Stuff: Air ASW (7/9/2011 5:17:28 PM)


quote:

ORIGINAL: Local Yokel
Incidentally, I think there is a case for introduction of an 'intermediate' class between the Mikuras and the Ukurus. This should consist of a Mikura A/S weapons fit on an Ukuru hull, and would reflect the fact that nine vessels built at Hitachi's Sakurajima yard were outfitted with the Mikuras' depth charge armament (2 X Type 94 Y-guns plus 2 stern rails), but allocated to the Ukuru class. The ships concerned were Hiburi, Daito, Shonan, Kume, Ikuna, Shisaka, Sakito, Mokuti and Habuto. In fact, taking this further, the Mikura class depth charge set-up in both stock and BigBabes appears to me to be completely wrong, and should be toned down as described for the Hitachi ships.

Enterprise recon photo of Maizuru, June 14, 1945. Otori and Hyabusa at dockside, Sakura on mooring bouys, unidentified Ukuru (possibly Inagi) under way from dock. Can make out three Type-94 Y-thrower installations, and two chutes on the afterdeck and fantail of the Ukuru.

Next is Ikuna, October 1944, with three Type-94 Y-thrower installations, and chutes visible on the afterdeck. Next is Uku, 1944, with a “low profile” afterdeck looking very much like Type-3 launchers with DCs inserted.

Last is a set of Ukuru drawings, both referencing 1944, the top labeled ‘early’ (looking very much like Ikuna), the bottom labeled ‘late’ (looking very much like Uku).


[image]local://upfiles/17451/8E9108764C314F379332B3514A11BFE9.jpg[/image]



JWE -> RE: ASW Stuff: Air ASW (7/9/2011 5:17:48 PM)

Mikuras are much harder to dial in. Mikura and Miyake seem to have left the yards with two Type-94s, two rails, and sweep gear. The sweep gear was removed and a third Type-94 substituted “approximately” 1944. Only late war pics of a Mikura is of the Kurahashi, in the NTMJ appendices, but unfortunately do not cover the afterdeck very well. However, the text notes the NTMJ supervised her disarmament, including “removal of her 12 depth charge launchers”. Conways gives Nomi, as completed, with 12 Type-3s.

Possible that Mikura and Miyake started life with 2x T-94s (going to 3x almost immediately), Awaji and Yashiro (Hitachi built ships) started life with 3x T-94s, and Kurahashi, Nomi, Chiburi, and Kusagi (all Tsurumi built ships) had 12 T-3s. Trust the IJN to make life complicated.

This is plausible on many levels and also comports with all the different configurations reported in the literature. Original Mikuras specified 60 DCs, going immediately to 120. Drawings of IJN stern racks show 6 DCs and the ready rack for a T-94 held 6. 2 racks and 3 T-94s gives 30 DCs topside and ready and 30 more (one full reload) in a magazine in the fantail. Increasing loadout means magazine triples in size (30 to 90). Means rip up the deck and rebuild the aft compartments (if there was even room).

If you’re gonna do that, why not just stick in a T-3 installation which is configured (rack, room, and space) for 120 DCs

[ed] so think we'll keep Babes at 3r, 3l, shooting T-95 DCs and let them upgrade to the same 3r, 3l, but shooting T-2s with double the ammo. A better DC, twice the total 'drops', all things considered it works for me. Can't (actually won't) play around with a "class for every ship". Too much of a pain in the butt, and the present abstraction works very well. But there's tons of empty slots in the neighborhood, so finely dividing the Kaibokan types shouldn't give you too much heartburn. Have at it.



mike scholl 1 -> RE: ASW Stuff: Air ASW (7/9/2011 5:36:02 PM)


quote:

ORIGINAL: treespider

quote:

ORIGINAL: mike scholl 1


quote:

ORIGINAL: Local Yokel

Ah "Scholl"… no, on second thoughts I'll not respond to your vacuous rehearsal of the obvious, as it will only encourage you to descend to the personal abuse in which you engaged in the "SLC = 15K VP" thread.


RIGHT! Wouldn't want any nasty old "Historical Realities" poking holes in your fantasies. [8|][8|][8|][>:]



To be fair Scholl the vast majority of the sinkings took place in 27 months (not 44) from 1/43 through 3/45.

Curious what the numbers would show if one were to compare ASW assets committed versus sinkings if one were to compare Pacific to Atlantic. for a similar time frame.

Versus the 40 some odd US subs lost to ALL Japanese ASW assets.

I do not know the answer just curious what the ratios would be?


As usual, you make some fair points "Spider". Everybody's ASW results got better as the war continued. On the Allied side it seems to have been the result of more and better equipment, weaponry, and tactics. You don't get results like the ENGLAND's without a superb ASW suite and advanced weaponry like "hedgehog" and "mousetrap". For the Japanese it seems to have been just a case of more rather mediocre assets chasing more and bolder Allied subs. What improved equipment they did deploy seems to have been in the air rather than the surface units. If I recall correctly, there wasn't much improvement in results by their surface units between 43 and 45, but the air assets became more effective. Neither held a candle to the effectiveness of the Allies.



mike scholl 1 -> RE: ASW Stuff: Air ASW (7/9/2011 10:17:53 PM)


quote:

ORIGINAL: mike scholl 1


quote:

ORIGINAL: treespider

To be fair Scholl the vast majority of the sinkings took place in 27 months (not 44) from 1/43 through 3/45.

Curious what the numbers would show if one were to compare ASW assets committed versus sinkings if one were to compare Pacific to Atlantic. for a similar time frame.

Versus the 40 some odd US subs lost to ALL Japanese ASW assets.

I do not know the answer just curious what the ratios would be?


As usual, you make some fair points "Spider". Everybody's ASW results got better as the war continued. On the Allied side it seems to have been the result of more and better equipment, weaponry, and tactics. You don't get results like the ENGLAND's without a superb ASW suite and advanced weaponry like "hedgehog" and "mousetrap". For the Japanese it seems to have been just a case of more rather mediocre assets chasing more and bolder Allied subs. What improved equipment they did deploy seems to have been in the air rather than the surface units. If I recall correctly, there wasn't much improvement in results by their surface units between 43 and 45, but the air assets became more effective. Neither held a candle to the effectiveness of the Allies.



Did some additional checking, and it's wierder than I'd remembered. US sub losses involving Japanese surface units were:

1942 - 02
1943 - 09
1944 - 07
1945 - 04

So Japanese ASW ships actually became LESS effective between 1943 and 1045!



Halsey -> RE: ASW Stuff (7/10/2011 2:14:03 AM)

bump...



inqistor -> RE: ASW Stuff (7/10/2011 5:45:10 PM)

quote:

ORIGINAL: vettim89
when I ran my naked ASW tests last year I found that ASW value does play a big role in a TF's ability to detect a sub that starts the turn with a detection level of 0. I ran a test bed scenario where all other factors were the same (same ships, same crew exp, same environment). What I changed was the ASW value. I stared with 2 then went to 3 then 6. With each succeeding increase I saw a higher number of detections then prosecutions by the ASW TF. The test had the ASW TF's deliberately passing over the top of undetected subs. So while the ASW value does not have an effect on the combat once it starts, it does seem to have an affect on if there will be combat.

That is quite interesting. Have you put this in forum somewhere?
That would indicate, that detection is done separately by every device. I am not sure that there is in-game sonar, but this could be way to simulate it.

quote:

ORIGINAL: Buck Beach
I have always thought there should be some way to account for those naval guns connected to a "fire control system". Maybe an accuracy penalty (separate devices) for the merchant ship's guns or other ships accordingly not having such systems.

I was also thinking about it, and main problem I have found is:
How to simulate DAMAGE for fire control system?

quote:

ORIGINAL: el cid again

I notice that in AE aircraft dedicated to hunting submarines do not carry ASW weapons.
They seem to rely on bombs. And to a lesser extent, on guns. Granted both are harmful
to submarines, still IRL all these aircraft ( and blimps ) carried DC - and sometimes no bombs
at all

I was wondering what will happen, when you set "alternative weapon" (there is such field in editor for Device) as DC? Some planes use SAP bombs against ships, and GP bombs against ground targets. And I can see, that is because they are set in "alternative weapon" field. Is it possible to use different weapon in ASW mission?

quote:

ORIGINAL: Local Yokel
On the subject of radar fitting dates, I went through all the kaibokan TROMS so far published on the combinedfleet site. Unfortunately these give no information at all about the 'Type 22' (strictly, 222 GÔ dentan) fitting dates, and very little about 'Type 13' (13 GÔ dentan) fit dates.

I have somewhere USNavy report, about Japanese Radars, and it seems almost as private venture every time (you know, TOP SECRET!). It is almost like:
"We have this ship in port, and here are some spare parts, lets do some wiring", and after visit in another port they add another cables, and after third visit, VOILA! Working radar. So it does not seem to be any plan for upgrades.
Granted, report is based solely on interrogations after war.

quote:

ORIGINAL: oldman45
Inqistor - I went back and looked at some old saves and I found that my experienced ASW TF's would run out of DC's on 1 and sometimes 2 of the ships if they made multiple attacks which they usually did. This was in the late 1943 time period. Based on what has been written here, since the more experienced crews are acquiring the target more often they attack more often. I didn't bother to look at the Japanese sunk ship list to verify kills but these groups did infact claim more kills after their attacks.

Still, I have not see ANY advantage for ship with larger number of AMMO, in FIRST encounter (or even second). It will NOT have RtB earlier, but only if used in ASW TF. And I am not sure ASW ships live long enough, on average, to reload (one torpedo hit should sink them).

quote:

ORIGINAL: mike scholl 1
Did some additional checking, and it's wierder than I'd remembered. US sub losses involving Japanese surface units were:

1942 - 02
1943 - 09
1944 - 07
1945 - 04

So Japanese ASW ships actually became LESS effective between 1943 and 1045!

Probably were chased away/sunk by air forces, before they could actually engage submarine.



JWE -> RE: ASW Stuff: Air ASW (7/10/2011 6:52:34 PM)


quote:

ORIGINAL: Local Yokel
On the subject of radar fitting dates, I went through all the kaibokan TROMS so far published on the combinedfleet site. Unfortunately these give no information at all about the 'Type 22' (strictly, 222 GÔ dentan) fitting dates, and very little about 'Type 13' (13 GÔ dentan) fit dates.

Wasn't quite what we were thinking of in terms of vetting. There's over 500 classes and dinking with intro dates for radar for each of them would be an impossible task. Maybe for a few, we can do it, but that's about it.

We're thinking more about radar device data. Did some analysis of some very well understood radar sets with respect to accuracy and resolution. One can get radial accuracy and distance resolution and in some cases altitude. Then adapted those values to game system requirements. Then ran specification comparisons against all the others and plotted the results.

Then found a decent place with all the base data for all nations, listed consistently. http://pwencycl.kgbudge.com/ (with 4 to 6 primary references for each and every radar). Ran our algorithm against their values and I will be dipped if they didn't plot out on the same curves, mostly. Okey dokey then. Modifying radar devices in accord with what we think is appropriate and what we have determined will fit within the game algorithm. Not huge, but a bit better and certainly smoother.



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