Hedgehogs & Mousetraps & Bears, Oh My - Not RHS

[herwin]

ORIGINAL: vettim89

ORIGINAL: JWE

ORIGINAL: AlaskanWarrior
JWE
Be happy to share the hamachi sushimi with you..

Oh gosh, send me some fresh Alaskan Halibut!! I'll be your Huckelberry forever!!

DC accuracy .. oh the horror .. the horror. It is not just a simple % chance to hit. There are some practical recommendations at the end of this, however.

The ‘accuracy’ numbers in the editor are evaluated very differently, depending on the “Device Type” of the weapon. For ASW weapons, the accuracy number gets evaluated against the target’s ability to evade (itself a function of speed, leader rating and maneuver), then gets multiplied by a hard coded number, then gets evaluated by combat range (which differs in shallow/deep water), then gets evaluated against cruise speed (if it’s a sub), then against target prior damage, then against day/night, and finally, after all the multiplication, division, subtractions, and comparisons, if the final number is too small, it is arbitrarily set to some nominal value, let’s just say, 2.

‘Accuracy’ is reduced in deep water, not ‘really’ by half, but this is a reasonable assumption. Combat range is a function of the sub’s depth (durability*10, for Class Type SS), but is arbitrarily set to 150’ for shallow water. So for a deep diver (300 footer), DC accuracy goes to half (sorta) in deep water, while for a shallow diver (maybe a 200 footer), DC accuracy only drops by 60-70% (sorta), in deep water. It’s ‘sorta’ because combat range is only one of the string variables, and is “adjusted” by the others.

Reasonable “editor” accuracy values for ASW weapons, thus don’t have much to do with IRL. IRL is useful, however, in determining “relative” values. If an IRL DC had a hit % of a billion to 1, the code promotes this to (effectively) 2%; so much for IRL.

Woof! So … the game code seems to like individual DCs with individual ‘accuracy’ figures between 4 and 10. The original game designers modeled things like Y and K guns and Hedgehogs, by adjusting the ‘accuracy’ parameters of the Devices (because you just can’t adjust the executable code). Not a bad way to go but, like everything else, it has implications. These will be dealt with in the next post.

Ciao. John

Well this is what I was afraid of. It seems the way the code is set-up, it is very hard, but not impossible, for a modder to affect ASW. With so many variables we cannot get at, we are left with but 2 - accuracy and effect. So it does seem to be quite the challenge. What I did not see in your interation John was a variable for the firing platforms experience. Is this in there?

That would be nice--skill dominated everything else and non-linearly. The average DD got about 0.0025 kills per launch using Hedgehog, but England got 0.25.

Most attacks involved multiple charges, in a pattern that provided good coverage. Whether the sub was sunk (or damaged) depended on the targeting for the pattern.

[el cid again]

[quote]ORIGINAL: JWE

Hedgehogs, in “game terms” are single installation launchers with multiple, substantially simultaneous, “rounds” in a launch. A typical Hedgehog fired maybe 20 projectiles in a salvo, each projectile having a 35lb torpex charge (somewhere earlier I wrote 65lbs, but that was the weight of the whole projectile – silly me).
[quote]


All Hedgehogs fired 24 rounds.

Not all Hedgehog ships carried only one - two was a common installation.

The design was set up for a German Type VII U Boot - it was the pressure hull of this (or a Type IX) the charge was intended to breach.
It was supposed to hit the hull - and the patterns tried (there were two - circular and oval - and there could be two of these in the same attack if two mounts) were supposed to guarantee one hit. For that reason each round does not have a separate chance of a hit - but the chance of a total salvo hit is high.

The limitiing problem is - this works only if the boat is shallow. You don't know his position close enough if he is deep (= more sinking time = more time to have moved) - and so it was not effective - and not even used - unless target was shallow. Our code will always attack - and we don't know if the sub is deep or not either - iti s abstract. So we must reduce accuracy by some factor to account for it only working at about periscope depth.

[el cid again]

ORIGINAL: JWE

Hedgehogs, in “game terms” are single installation launchers with multiple, substantially simultaneous, “rounds” in a launch. A typical Hedgehog fired maybe 20 projectiles in a salvo, each projectile having a 35lb torpex charge (somewhere earlier I wrote 65lbs, but that was the weight of the whole projectile – silly me).



Due to how the code functions in terms of ‘passes’ and ‘chances’, and especially in terms of how Nik/Mike Wood/Michaelm tweaked the damage calculation routines, it seems reasonable to implement hedgehog, etc.. devices as follows:

On our exemplary DD, the BigB, Wpn 114 has a “Num” of 20 (this is the number of projectiles), turrets = 1 (single installation), “Ammo” of 6 (assuming a hard humping set of sailors doing the reloads).

If the BigB detects a sub, the first ‘shot’ from Wpn 1 will deliver 20 cans of soup, each with an ‘effect’ of 35, and each having a ‘chance’ to cause damage. It means you will have to sit through 20 iterations of the combat screen for each shot, but what the hey.

So bottom line, I think the best implementation, given how the code works, is to set “Num” to the number of projectiles in a shot, and keep each projectile’s effect at its stock value. Ciao.

John

Aside from the fact we need to reduce the number of hits to get in the ball park

there should never be a chance for more than two hits per pattern.

Or possibly there might be two hits - if the target was long - and the pattern was perfectly centered - one at each end. A Type IX - but not a Type VII - so to speak. But a perfect centered pattern would not happen.

Using your proposal we get 20 chances - and if they are high (say like in stock or most mods) - you are going to get 12 hits for those 20 chances.

I don't think you get more than one shot per attack - but I do think you get more than one attack often. If you don't use all the reloads - they can be used on the next detection - on the same or different sub later in the day or on a different day. So the reloads should always be the total number of salvos carried on the ship. In USN this was six patterns per mounting (Naval Weapons of World War Two).

[el cid again]

ORIGINAL: JWE

ORIGINAL: herwin
It's a bunch of projectiles in a uniform pattern--if one hits, it's unlikely another will. The one that hits does its damage. The easiest way to model this is as 35 pounds of torpex with a reasonable probability of a critical hit.

Which is about as close as the proposed model can get it, given the algorithm.

The use of contact fusing makes it harder for the sub to creep away and allows additional shots. The escorts are more concerned with keeping the sub suppressed (relatively easy once detected) than killing it (quite hard). The sub can't run, so it has to stay quiet and wait out the escorts.

But since the code doesn't know contact fuses from horseradish, this isn't particularly useful.

It need not know. This can be handled statistically.

A HH warhead does damage when it CONTACTS the target. A DC warhead does damage when with 6 to 9 meters range of the target.
We can use statistics to figure out the chances of a hit for any given pattern - at least at the depth that hits were likely - shallow.
And the code does have durability = depth - so it at least crudely says "deeper is harder to hit" - which is probably good enough.

With HH the problem is mainly "do we know where he is" - and because he is shallow - the answere is "pretty closely" - so the hit chances are a lot better than 1 in 100 for a big DC pattern.

[el cid again]

ORIGINAL: JWE

ORIGINAL: herwin

ORIGINAL: Monter_Trismegistos

Does "effect" plays a role during hit probability resolution? How "accuracy" works then?

That's for the game designers to talk about. I'm only describing how we analyse it operationally.

Harry, how the game designers did it is precisely what these threads' topics are about. Operational analysis is something that actually belongs elsewhere. Monter's questions are well taken and directly on topic.

"effect" does play a role, in that "hit probability" and "damage" are wrapped up into one big chunky calculation. I'm checking with the guys who did the latest code to see if they did anything additional to accuracy. Soon as I find out, we'll see how accuracy works in the current version. Ciao.

John

We know for bombs and guns and other things this works as a product - and the manual itself explains how for small rapid fire guns you can multiply shell weight times ten while dividing ROF (accuracy) by ten - and it works for shells otherwise too small. By this means we have made some other weapons work too. Likely it is similar - and to what JWE implied above - when he said they were wrapped into one calculation. They are usually a product - and so one can get at the answer by changing either. Aside from talking to code writers - this also can be established by testing - and since code does not always do what the writers intended it to do - it may be more reliable to note what really happens vice what they wanted to happen. It is very likely this works the same as in most WITP code - and we can verify that if we need to. It just takes time.

[el cid again]

ORIGINAL: witpqs

Did the Hedgehog (& Mousetrap) warheads have shaped charges? If so then maybe the 35 pounds should have an effect greater than the way the code would interpret 35 pounds.

No. "This was a 24 spigot mortar fring 7 inch diameter contact-fused projectiles weight 65 pounds with a 35 pound charge." They are flat nosed - and the warhead part is a cylendar - the tail having fins to help stabollize flight. They were supposed to sink heavy (warhead) end first - and "Sinking speed was 22-34.5 f/s and the the spigots which were arranged with six in each of four vertical rows were angled to give a 40 yard diameter circle at c200 yards ahead of a stationary ship." Naval Weapons of World War Two.

In my time most old destroyers still mounted HH - and I was able to see many of them up close - this description is correct.

[el cid again]

ORIGINAL: AlaskanWarrior

ORIGINAL: herwin


It's a bunch of projectiles in a uniform pattern--if one hits, it's unlikely another will. The one that hits does its damage. The easiest way to model this is as 35 pounds of torpex with a reasonable probability of a critical hit. The use of contact fusing makes it harder for the sub to creep away and allows additional shots. The escorts are more concerned with keeping the sub suppressed (relatively easy once detected) than killing it (quite hard). The sub can't run, so it has to stay quiet and wait out the escorts.

I do not see how it would be unlikely more than one would hit. A 160 by 140 foot elliptical or a 200 foot circle would have a good probability of two hits, with three probably not uncommon, since most subs are over 200 feet in length. Indeed rereading the exploits of the USS England and her famous 6 subs in 12 days exploit, note that an explosion with a hedgehog meant a hit:

Sub one:

"On the second hedgehog attack, two explosions were obtained four seconds after the projectiles hit the water"

"On the fifth attack, two or three hedgehog explosions were heard twelve seconds after striking the water and a fathometer reading of 54 fathoms was obtained"

Sub two

"18.2 seconds after firing the second patterns three or more hedgehog projectiles detonated,"

sub three:

"On the second attack some 8 to 10 hedgehog hits were obtained 14.5 seconds after the charges struck the water."

etc, etc,
http://de635.ussengland.org/enclosure_b.htm

I would not change the code any for hedeghogs as it is obvious by operational experience that more than one hit was possible per pattern.

The British designed the weapon so one hit was certain IF the pattern was anywhere over the target. It was designed to work on a short submarine - and if not perfectly centered - it would not hit such a target more than one time. But in fact many submarines were larger than that - more so in PTO - and so both due to length and width there was some chance of two hits - if you did not hit dead center then two rounds might hit a wide submarine. And if you were dead center - you might get two hits on the other end of a long submarine.

The problem we have is that we don't know (code ignores) the size of the target - so a small submarine should not be hit more than one time.

A bigger problem we have is we are getting far too many hits. This is made worse because even an accuracy of 1 is way better than pk 1 in 1000 - which is the right ball park. So we have to play statistical games IF we want to simulate - and if we are not content to have subs sunk are too often and far too easily. The model is typical GG - very simple - crude even - but has important elements in the ball park. It also is very overstated - as bad or worse than mines are far too easy to clear - and clear fast.

I am not sure how to do this - but ASW took a very long time - many hours - and should take up to two days if properly done. [He runs out of battery pretty fast - and cannot go far. He needs air. IF you did not kill him - he is going to come up - pretty close to where he was. Stick around - if he does no come up in three days - he never will.]

[el cid again]

ORIGINAL: herwin

ORIGINAL: witpqs

Did the Hedgehog (& Mousetrap) warheads have shaped charges? If so then maybe the 35 pounds should have an effect greater than the way the code would interpret 35 pounds.

After getting told that the Hedghogs were designed to get multiple hits, I did a little research. My background is OR (and Cold War ASW, where individual warheads were designed to kill rather than damage the boat). My original reference was Morse and Kimball, Methods of Operations Research. The Squid mortar was the successor to the Hedgehog and functioned much like I described, with a pattern of three contact-fused mortar rounds. In 1944-45, it killed about one sub in three that was attacked (with one or two shots). Hedgehog fired a salvo of 24 charges, that landed in a 30m diameter circle at a fixed point relative to the ship. One to two hits were enough to sink a submarine, but there were no near misses, so it was an all-or-nothing weapon. Given that there was one sub sunk per about 1000 charges expended, one attack in 40 was effective. (The best kill rate seen was 25%.) That suggests the key factor was targeting accuracy, which is sensitive to crew/captain skill (on both sides) and sensor effectiveness. The right way to model this is to treat the weapons system as a single shot at a time, with the probability of hitting non-linearly sensitive to skill (most crews having low skill) and the probability of a critical hit given a hit being 100%. Hedgehog supplemented depth charges. Pictures here.

Mousetrap was an ASW rocket system that replaced Hedgehog. About 100 ships had it. No data on effectiveness.

HH did achieve multiple hits on occasion. It was DESIGNED for one hit. The idea was a cheap system that would kill the mass produced "minimum U boat" of Donitz.

Mousetrap was indeed a rocket system but only in the sense HH was - the rocket is in the round which is fired - but it did not replace HH - which long outlived it. It was a simultaneous invention for vessels too small to use HH. Originally designed for an 85 pound round, this was too hard to handle in a rough sea, so the 65 pound HH round was substituted. In the end it became a four round system with the same "bullet" but no spigot mortar - rather rails. The small number of rounds were probably less likely to hit - and the pattern and range were greater - so the PK was probably less. Analysis of the range (300 yearsds) and size (240 feet pattern) implies it would be about 2/3 as effective per round - and since you fire 1/6 as many rounds - that is 1/18 as effective per pattern.

[JWE]

ORIGINAL: AlaskanWarrior
I would not change the code any for hedeghogs as it is obvious by operational experience that more than one hit was possible per pattern.

It's good that you wouldn't change the code, since the code can't be changed; arh, arh, arh [:D] (wish there was a pirate smiley face)

Anyway, the utility is grinding away and doing a Shewheart for each accuracy metric. Should have a good mean/sigma for practical results as applied to a range of editor accuracy numbers.

Should wrap this puppy up very soon. Ciao.

John

[akdreemer]

ORIGINAL: el cid again

ORIGINAL: AlaskanWarrior

ORIGINAL: herwin


It's a bunch of projectiles in a uniform pattern--if one hits, it's unlikely another will. The one that hits does its damage. The easiest way to model this is as 35 pounds of torpex with a reasonable probability of a critical hit. The use of contact fusing makes it harder for the sub to creep away and allows additional shots. The escorts are more concerned with keeping the sub suppressed (relatively easy once detected) than killing it (quite hard). The sub can't run, so it has to stay quiet and wait out the escorts.

I do not see how it would be unlikely more than one would hit. A 160 by 140 foot elliptical or a 200 foot circle would have a good probability of two hits, with three probably not uncommon, since most subs are over 200 feet in length. Indeed rereading the exploits of the USS England and her famous 6 subs in 12 days exploit, note that an explosion with a hedgehog meant a hit:

Sub one:

"On the second hedgehog attack, two explosions were obtained four seconds after the projectiles hit the water"

"On the fifth attack, two or three hedgehog explosions were heard twelve seconds after striking the water and a fathometer reading of 54 fathoms was obtained"

Sub two

"18.2 seconds after firing the second patterns three or more hedgehog projectiles detonated,"

sub three:

"On the second attack some 8 to 10 hedgehog hits were obtained 14.5 seconds after the charges struck the water."

etc, etc,
http://de635.ussengland.org/enclosure_b.htm

I would not change the code any for hedeghogs as it is obvious by operational experience that more than one hit was possible per pattern.

The British designed the weapon so one hit was certain IF the pattern was anywhere over the target. It was designed to work on a short submarine - and if not perfectly centered - it would not hit such a target more than one time. But in fact many submarines were larger than that - more so in PTO - and so both due to length and width there was some chance of two hits - if you did not hit dead center then two rounds might hit a wide submarine. And if you were dead center - you might get two hits on the other end of a long submarine.

The problem we have is that we don't know (code ignores) the size of the target - so a small submarine should not be hit more than one time.

A bigger problem we have is we are getting far too many hits. This is made worse because even an accuracy of 1 is way better than pk 1 in 1000 - which is the right ball park. So we have to play statistical games IF we want to simulate - and if we are not content to have subs sunk are too often and far too easily. The model is typical GG - very simple - crude even - but has important elements in the ball park. It also is very overstated - as bad or worse than mines are far too easy to clear - and clear fast.

I am not sure how to do this - but ASW took a very long time - many hours - and should take up to two days if properly done. [He runs out of battery pretty fast - and cannot go far. He needs air. IF you did not kill him - he is going to come up - pretty close to where he was. Stick around - if he does no come up in three days - he never will.]

The question is will one hedgehog hit sink a sub in the game? If not then we need multiple hits.

[herwin]

ORIGINAL: JWE

ORIGINAL: vettim89
Well this is what I was afraid of. It seems the way the code is set-up, it is very hard, but not impossible, for a modder to affect ASW. With so many variables we cannot get at, we are left with but 2 - accuracy and effect. So it does seem to be quite the challenge. What I did not see in your interation John was a variable for the firing platforms experience. Is this in there?

Yes, it is difficult, but i will post relevant values and their spreads. A challenge, yes, but that is what these threads are devised to address. Once you really understand who does what to whom, it's a lot easier to figure out what you can do to tweak things your way.

To answer your explicit question, experience is a function of the detection routine, and not the firing routine. Six, hard humping gorillas, will fire the same as six Einsteins. However, six Einsteins will find the target way before six gorillas. Does this make sense???

Ciao. John

On my,

Being good at searching and tracking does not imply you're good at engaging the target. The last was what differentiated good ASW teams from the large masses.

[JWE]

ORIGINAL: AlaskanWarrior
The question is will one hedgehog hit sink a sub in the game? If not then we need multiple hits.

Probably not.

Okey dokey Alaska, here it is. Woof! The poor CPU is pretty hot; I could probably do a hamachi kama on the radiators.

M’kay, ran tests so as to get 33 detects from ASW TFs. For each detect, the ship drops its cans o’ soup. Tests had hedgehogs in 4 different configs. Device 114 is the only ASW wpn assigned to the ships.

Wpn – “Num” = 20, Turrets = 1 (Device 114 – Accuracy = 8, Effect = 35)
Wpn – “Num” = 20, Turrets = 1 (Device 114 – Accuracy = 4, Effect = 35)
Wpn – “Num” = 1, Turrets = 1 (Device 114 – Accuracy = 160, Effect = 35)
Wpn – “Num” = 1, Turrets = 1 (Device 114 – Accuracy = 160, Effect = 700)

Sets 3 and 4 are derivatives of set 1 and 2, with ‘accuracy’ multiplied by “num” in set 3, and both ‘accuracy’ and ‘effect’ multiplied by “num”, in set 4. The ASW TFs utilizing these weapons are uniform, with all ships having identical leader ratings (50) and identical day/night skill ratings (50/25). The target sub has a nominal leader rating of 50.

Test 1 develops an average of 8 “hits’ out of 20 projectiles; some in the “near miss +, ++, +++, or ++++” range. Test 1 develops a mean of 0.106 “critical” hits. Test 1 causes a mean damage of 22 sys, 36 flot, 2 eng on the target.

Test 2 develops an average of 5 “hits” out of 20 projectiles; some in the “near miss +, ++, +++, or ++++” range. Test 2 develops a mean of 0.113 “critical” hits. Test 2 causes a mean damage of 18 sys, 37 flot, 4 eng on the target.

Test 3 develops an average of 0.164 “hits” out of 1 projectile. That means 6 attack runs to get 1 hit. Of the hits, many are in the “near miss +, ++, +++, or ++++” range. Test 3 causes a mean damage of 27 sys, 44 flot, 3 eng on the target.

Test 4 develops an average of 0.159 “hits” out of 1 projectile. That means 6 attack runs to get 1 hit. Of the hits, many are in the “near miss +, ++, +++, or ++++” range. Test 3 causes a mean damage of 24 sys, 39 flot, 2 eng on the target.

‘Critical’ hits are within the 0.1 range for all tests. Basically in accord with the code, so, duh.

I like set 2. That’s what I use and it works well. Other sets are at the desire of the modder. This is sorta how they play. Ciao.

John

[el cid again]

Since there would probably never be 5 hits with 24 projectiles - why do you like that?

Since there were 24 projectiles - why do you keep using 20?

Since most HH salvos would not hit - they only hit IF they are correctly aimed - and from a moving platform vs an unseen moving target in a moving seaway that is problematical - not to mention there is a chance the entire datum being attacked is not a submarine (in fact that happens MORE OFTEN than a real submarine is the datum point - even today probably)

and since a HH should when it does hit generate a single impact - otherwise most likely 2 hits -

again I wonder - why do you like 5 hits?

[JWE]

ORIGINAL: AlaskanWarrior
The question is will one hedgehog hit sink a sub in the game? If not then we need multiple hits.

Well Alaska, best answer is uh … maybe. Don’t forget that any ASW weapon will only drop “Num” cans of soup in an attack and only gets “Ammo” attacks (potentially). There is a limit (random) on the number of attacks, so even if “Ammo” is big, you won’t get more than, let’s say 7, and likely no more than 3 or 4. The incidence of a ‘critical’ hit is also small within the realm of ‘hits’. So to maximize your chances, increase “Num”.

[el cid again]

Naval Weapons of World War Two - British section - the longest of two HH articles - says it "rarely" produced a confirmed kill. It was designed to kill a Type VII if it hit the deck - by cracking the pressure hull. But a hit mignt not be on the deck - it might not be near enough to the pressure hull to crack it - and German pressure hulls turned out to be harder to crack than designed to be or understood at the time. HH became unpopular - in its long use - because it was NOT likely to produce a "one shot one kill" outcome - only damage if you were on target.

For this reason wanting to get a kill in a single attack is probably not the goal we should be after. Submarine kills are rarely on the model of USS England - one pass - one kill - definitive knowledge you got that - and then ONLY due to crew skills - which do seem to be in our model here. It should be only exceptionally possible - not the SOP.

For a one shot one kill weapon - consider one of several ASW torpedoes - which were three times as likely to kill as a full size DC attack - itself more likely to kill than a HH attack - I am considering modeling one on a statistical basis - combining the Mousetraps to get the slot

[JWE]

ORIGINAL: JWE

ORIGINAL: AlaskanWarrior
The question is will one hedgehog hit sink a sub in the game? If not then we need multiple hits.

Well Alaska, best answer is uh … maybe. Don’t forget that any ASW weapon will only drop “Num” cans of soup in an attack and only gets “Ammo” attacks (potentially). There is a limit (random) on the number of attacks, so even if “Ammo” is big, you won’t get more than, let’s say 7, and likely no more than 3 or 4. The incidence of a ‘critical’ hit is also small within the realm of ‘hits’. So to maximize your chances, increase “Num”.

Oh, dude!! If you want to have a ton of fun, just think: the algorithms for escorts attacking subs are different from the agorithms for an ASW TF attacking subs.

Oh, we got serious fun now, kinda like actioning by transformational defenestration of obstructions.

John

[akdreemer]

ORIGINAL: JWE

ORIGINAL: JWE

ORIGINAL: AlaskanWarrior
The question is will one hedgehog hit sink a sub in the game? If not then we need multiple hits.

Well Alaska, best answer is uh … maybe. Don’t forget that any ASW weapon will only drop “Num” cans of soup in an attack and only gets “Ammo” attacks (potentially). There is a limit (random) on the number of attacks, so even if “Ammo” is big, you won’t get more than, let’s say 7, and likely no more than 3 or 4. The incidence of a ‘critical’ hit is also small within the realm of ‘hits’. So to maximize your chances, increase “Num”.

Hmmm better you than me thinking on this.


Oh, dude!! If you want to have a ton of fun, just think: the algorithms for escorts attacking subs are different from the agorithms for an ASW TF attacking subs.

Oh, we got serious fun now, kinda like actioning by transformational defenestration of obstructions.

John

Ideally the ships in an ASW task force would prosecute a target the longest, specifically going for a kill. They would also have the most experienced crews/commanders for ASW work. So I can see the ASW task force having better detection, but the ships in the TF also need to have increased chance that more of them will attack the target. Like wise I would limit the number of ships in a ASW taskforce to six max in the code.

The ships in an escort TF would only strive to keep the sub down till it was unable to attack the other ships in the task force. So I would not expect them to be as proficient in ASW.

What is actually needed are air/surf/subsurface proficiency modifiers for the crew and commander. But since this involves a radical change in code probably not going to happen.

[akdreemer]

ORIGINAL: el cid again

ORIGINAL: JWE

Hedgehogs, in “game terms” are single installation launchers with multiple, substantially simultaneous, “rounds” in a launch. A typical Hedgehog fired maybe 20 projectiles in a salvo, each projectile having a 35lb torpex charge (somewhere earlier I wrote 65lbs, but that was the weight of the whole projectile – silly me).

All Hedgehogs fired 24 rounds.

Not all Hedgehog ships carried only one - two was a common installation.

The design was set up for a German Type VII U Boot - it was the pressure hull of this (or a Type IX) the charge was intended to breach.
It was supposed to hit the hull - and the patterns tried (there were two - circular and oval - and there could be two of these in the same attack if two mounts) were supposed to guarantee one hit. For that reason each round does not have a separate chance of a hit - but the chance of a total salvo hit is high.

The limitiing problem is - this works only if the boat is shallow. You don't know his position close enough if he is deep (= more sinking time = more time to have moved) - and so it was not effective - and not even used - unless target was shallow. Our code will always attack - and we don't know if the sub is deep or not either - iti s abstract. So we must reduce accuracy by some factor to account for it only working at about periscope depth.

Okay, please define shallow and deep in numbers and not some ephemeral term. I calculated that the hits on the third sub England sank were roughly 140 feet deep (18.5 sec from launch, ~12 sec flight time so 6.5 seconds of sink at 22 fps = ~140 feet).

[JWE]

ORIGINAL: AlaskanWarrior
Ideally the ships in an ASW task force would prosecute a target the longest, specifically going for a kill.

This is accommodated. There are 4 attack intensities (average number of attack passes), with the highest going to anti-sub TFs. The lowest intensity is assigned to escorts in a “gotta get there, and ain’t got time to mess with you” TF, like ‘fast transport, etc. The middle two are divided between escorts in a SurfCom type, and a Movement type, depending on the ‘value’ of the ships being protected.

They would also have the most experienced crews/commanders for ASW work. So I can see the ASW task force having better detection, but the ships in the TF also need to have increased chance that more of them will attack the target. Like wise I would limit the number of ships in a ASW taskforce to six max in the code.

Experience is only treated in terms of the leader’s Nav rating and the Exp rating (day and night) of the ship. A TF escort has an additional variable in the contact analysis that pertains to the sub skipper’s ‘aggression’ rating. An aggressive sub skipper will be more amenable to detection. Once detection happens, there’s just one block of code that deals with dropping cans of soup.

The ships in an escort TF would only strive to keep the sub down till it was unable to attack the other ships in the task force. So I would not expect them to be as proficient in ASW.

And that’s what the different attack intensities attempt to do; 2 or 3 attack ‘passes’ might ‘ding’ the sub, but certainly help keep her out of the parameters necessary for a torpedo attack. 4, 5, 6 or 7 attack ‘passes’ will do more than that, especially where each ‘pass’ involves sum o’ “Num” cans o’ soup.

What is actually needed are air/surf/subsurface proficiency modifiers for the crew and commander. But since this involves a radical change in code probably not going to happen.

Yep, to both. Bifurcating Nav into Surf/ASW is a very good idea; wish it was higher in the priority list at the get-go, but .. %work !> %return. Maybe in a monster patch, but still, not really likely.

John

[el cid again]

ORIGINAL: AlaskanWarrior

ORIGINAL: el cid again

ORIGINAL: JWE

Hedgehogs, in “game terms” are single installation launchers with multiple, substantially simultaneous, “rounds” in a launch. A typical Hedgehog fired maybe 20 projectiles in a salvo, each projectile having a 35lb torpex charge (somewhere earlier I wrote 65lbs, but that was the weight of the whole projectile – silly me).


Okay, please define shallow and deep in numbers and not some ephemeral term. I calculated that the hits on the third sub England sank were roughly 140 feet deep (18.5 sec from launch, ~12 sec flight time so 6.5 seconds of sink at 22 fps = ~140 feet).

Shallow varies slightly with the submarine. But in principle, shallow means periscope depth or slightly deeper. For a German submarine Periscope depth is 30 meters. For USN it is 100 feet for most large submarines. These values are almost identical and for our purposes are identical. If a submaine is not using its periscope - it will go somewhat deeper to be safe from the hulls of ships overhead: "depth" is keel depth - so the TOP of the submarine is very close to the surface. Typical values are 120 to 150 feet - and your 140 feet may be reasonable - if somehow they had recorded the time of sinking from impact with the water to detonation. It may not be quite right if nobody compensated for the time the sound takes to reach the person with the stopwatch - in which case it might be slighly less than 140 feet. But that does constitute shallow. If depth was set in meters - and if the sub was not changing depth - it might have been 40 meters was the setting.

The discussion in Naval Weapons does not give depth figures - just the term shallow. But in this period "deep" was 200 or 300 feet for a pre war design - and 450 to 500 feet for a later design. Shallow has to mean significantly less than these values. Deep only is a way to mess up depth charges - these values are pretty much not going to help you get under the layer - and they layer was not understood very well (or at all) in that period - nor does it always exist. Deep is used because shallow settings won't work - the distance to charges exceeds 10 meters - so they don't do much damage - and they cannot know what setting to use. [Late in WWII RN introduced a real depth finding set - and used that with Squid - setting Squad charges for actual target depth - or if two Squid present - setting them bracketed above and below the target depth. But before that rules of thumb and educated guesses were what was used: if a German sub went deep there were two settings a commander would use - the deeper of these was 740 feet - a brilliant guess - but what if it was at 300 feet? or 450 feet? or 900 feet? You see the problem. ] Hedgehog was effective if the sub had just submerged or been at periscope depth - and with aircraft in company (the England case) they could see the sub - if deep they could not - so that was another way to tell - if the planes see the target hit it with hedgehog. When U-505 was captured, the planes could not talk to the AS ships - but they "communicated" its position by firing machine guns into the sea - and it worked. The AS ships interpreted that point as the datum and attacked with enough effect to force it to surface.