RE: damagelethality of depth charges

RE: damagelethality of depth charges (Full Version)

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Terminus -> RE: damagelethality of depth charges (6/29/2006 6:11:24 PM)
Once the Mid-Atlantic Air Gap (aka the Black Hole) was closed by long-range aircraft, that was the end for the U-Boats. BTW, I'd always thought the FIDO wasn't that effective?

rtrapasso -> RE: damagelethality of depth charges (6/29/2006 6:24:24 PM)
quote: ORIGINAL: Terminus Once the Mid-Atlantic Air Gap (aka the Black Hole) was closed by long-range aircraft, that was the end for the U-Boats. BTW, I'd always thought the FIDO wasn't that effective? Depends what you mean by "effective"... i think it had around a 25% kill rate, and they were pretty small so you could carry several in a bomber.

Sardaukar -> RE: damagelethality of depth charges (6/29/2006 6:25:37 PM)
quote: ORIGINAL: Terminus Once the Mid-Atlantic Air Gap (aka the Black Hole) was closed by long-range aircraft, that was the end for the U-Boats. BTW, I'd always thought the FIDO wasn't that effective? From Uboat.net: http://www.uboat.net/allies/technical/fido.htm Number of MK24s launched against submarines 204 Total number of submarines sunk by FIDO (German & Japanese) 37* Total number of submarines damaged 18 Not too bad, over 25 % hit rate.

Nikademus -> RE: damagelethality of depth charges (6/29/2006 6:29:15 PM)
FIDO wasn't particularily effective though it improved with time. Aircraft actually scored most of their kills/damage using conventional bombs. To me, FIDO just added to the growing list of technological challenges facing the Uboats as time went by. But in the end, it was simply the presence of aircraft that was the decisive factor.

Sardaukar -> RE: damagelethality of depth charges (6/29/2006 6:32:20 PM)
True. FIDO was effective against subs that had time to crash dive and thus was making lot of propeller noise. Aircraft itself was deciding factor in that, indeed, no matter what kind of weapons it carried as long as effective.

spence -> RE: damagelethality of depth charges (6/30/2006 4:38:19 AM)
There is a old S&T mag out there somewhere with a table of how many U-Boats got killed by what combination of what....think it's the issue with the game "Wolfpack" in it. In any case the sample of dead U-Boats is so large that even if surface ships alone only accounted for a third that's over 200 kills.

RUPD3658 -> RE: damagelethality of depth charges (6/30/2006 6:29:43 AM)
quote: ORIGINAL: Terminus Next he'll be lecturing us in his usual condescending tone that flak was ineffective as well It knocked down only about 2% of attacking aircraft IRC. This may have been the numbers for attacking heavy bombers in WW2 but I recall using this stat (got it from someplace official) during a debate class in High School to show why the Star Wars missle defense system would not work.

dtravel -> RE: damagelethality of depth charges (6/30/2006 11:05:39 AM)
But I've also heard that AA was the defense most hated/feared by Allied bomber crews because there was absolutely nothing they could do about it. They couldn't shoot back, they couldn't try to dodge it because they would be on their bomb runs and they could see it going off all around them. In game terms that would equate to a morale hit even if few aircraft are damaged or destroyed.

Speedysteve -> RE: damagelethality of depth charges (6/30/2006 12:27:13 PM)
Agreed dtravel. The 8th crews HATED it. The only enemy they could not hit back at. Became even more pronounced into 44 when on most missions the LW did not interfere en masse and the number of flak guns employed increased. Politz alone had 220+ HAA[X(]

Sardaukar -> RE: damagelethality of depth charges (6/30/2006 3:29:01 PM)
That's why infantryman also hates both artillery and sniper fire. Both are very unnerving because there is usually not much to do to fight back, just try to take cover. Even worse in bomber plane vs. flak..cannot even do that.

spence -> RE: damagelethality of depth charges (7/1/2006 5:05:35 AM)
UBoat.net lists the causes of loss for German U-boats in WW2 as follows: 3 captured 35 to mines 43 to bombing in port 37 to combined operations of ships and aircraft 250 to aircraft alone while at sea 264 to ships alone (includes several sunk by merchant ship guns) 53 to unknown causes Interesting in that one needs to combine the sunk by bombing in port with sunk by a/c at sea to exceed the number sunk by ships alone. Personally I had thought that a/c sinkings exceeded ship sinkings of UBoats by a substantial margin. Oops; didn't read to bottom of page: 32 more lost: 25 to accidents or friendly fire 4 taken over by Japan after German surrender 2 interned by Spain 1 sunk by SOVIET SHORE BATTERIES

el cid again -> RE: damagelethality of depth charges (7/1/2006 1:43:29 PM)
quote: ORIGINAL: spence quote: Sub hulls are round - and are able to survive even a nuclear shockwave at remarkably short ranges! They simply reflect the wave 750 dead UBoats must be wrong!!! At least you are consistent! Generally overlooking the significant data: how many of those 750 UBoats were sunk by depth charges? How many by contact detonating weapons like Hedgehog? How many by torpedoes? How many by mines? How many by bombs? How many by rockets? How many by gunfire hits? How many by a combination? More significantly still, how many subs were ENGAGED with depth charges? While there is no way to answer the question, surely it is more than in any other campaign in history. The effectiveness of depth charges is dismal. Most escorts never damaged an enemy submarine - even if they engaged several or many times. [The great, glorious exception is USS England - of course - but note they don't often mention she had an entire task group including a CVE in attendence - and no one alleges she got them without using her Hedgehogs.]

el cid again -> RE: damagelethality of depth charges (7/1/2006 1:50:32 PM)
quote: ORIGINAL: Terminus quote: ORIGINAL: ChezDaJez Actually El Cid isn't far wrong this time. The outer hull was whatever shape the designers decided on but the pressure hull (inner hull) of most WWII submarines was round or oval shaped. Basically all the ballast piping and fuel cells were located between the hulls. Most designers did create somewhat oval outer hulls for improved seakeeping abilities when on the surface. Chez My problem is the "a submarine can withstand a nuclear pressure wave" claim... If you are going to have a problem, at least don't chop of the qualifing clause from the sentence: - I didn't say at ANY range - If you look at actual test data you will be impressed with how close you can be without doing structural damage to a submarine with a nuclear weapon. It is nothing like what you would expect. It is not the same thing as saying you won't get the sub if you are close enough - far from it. Nevertheless, we had a problem with nuclear depth charges not being very effective. IF you could locate the target sub, you could use modern non-nuclear weapons with a high degree of effect. If you could not locate the target, firing nuclear depth charges didn't solve the problem. [There was the Russian concept of "sterilization" - fly heavy bombers on parallel courses - and drop a charge every so often - not so much because it would kill any subs as because it would surely render them deaf and unable to detect anything. But that is not what I am talking about. A trainee ordering use of a nuclear ASROC was a sure sign of a trainee in trouble. It wasn't going to work.]

el cid again -> RE: damagelethality of depth charges (7/1/2006 2:03:34 PM)
quote: ORIGINAL: spence I think the ASW routines are pretty good now. Taken in isolation Cid's comments re ASW give the impression that ASW in WW2 was pretty ineffective. Close to 1000 dead axis subs from that conflict belie that contention. Yes, airplanes, mines, bombs, acoustic torpedos and accidents all killed some, perhaps the majority, but plain old depth charges killed a very statistically significant number. The same is very large, larger than any other class except merchies. Spence has a remarkable ability to reason from conclusions: since he already "knows" the truth - he looks for reasons he must be correct. He does not consider the entire data set: the sheer number of submarines sunk, even by depth charges (if we allow it is large - which I will only for this point) - is in itself NOT an indication that a SINGLE depth charge is likely to kill a submarine - the topic under discussion. WHEN depth charges kill a submarine they virtually always do so due to CUMULATIVE damage - and one can never say "DC number 3 of salvo number 7 was the fatal one" - and could not even if one had perfect telemtry data on every attack in WWII. It is much more remarkable how LOW the chance is of a fatal hit is PER DC than it is true that they are effective weapons. Note that I formally studied ASW in a USN school and served on a US destroyer with a secondary ASW mission - and even got to play with US and Soviet submarines on occasion. Anyone who thinks ASW is easy does not understand the subject! This was much worse in WWII. The greatest of IJN destroyer commanders - Takishi Hara - tells us of his first attack on a US submarine. The submarine is identified, and recorded his attack in its log. But his DCs were NOT fatal - and we can read the log because they were not - and his ASSUMPTION they MUST HAVE BEEN effective was flawed - based on an exaggerated (but still popular) view of DCs. It is quite normal not to be sure there is a target at all - and it is normal not to know what you did to the target - even today. Note that US WWII ASW doctrine was not based on the concept of "kill enemy submarines." It was based on the concept of "get the escorted ships through" - a very different mission. If you could mess up the submarine's situation to the point it could not deliver torpedoes or mines effectively, you won - and you didn't have to sink it to do that. Only late in the war (see the case of USS England and its TF rolling up an entire patrol line in a week) was it possible to be aggressive in the sense implied by "one DC should be fatal." And even then, it was not true one DC had a good chance of inflicting fatal damage - but a TEAM of ships and planes using MANY DCs and other weapons did have a good chance.

Terminus -> RE: damagelethality of depth charges (7/1/2006 2:10:30 PM)
Who here has claimed that ASW is "easy"? The only one who's even used that word is you, cid, twice now...[sm=crazy.gif][sm=nono.gif]

el cid again -> RE: damagelethality of depth charges (7/1/2006 2:10:52 PM)
quote: ORIGINAL: spence UBoat.net lists the causes of loss for German U-boats in WW2 as follows: 3 captured 35 to mines 43 to bombing in port 37 to combined operations of ships and aircraft 250 to aircraft alone while at sea 264 to ships alone (includes several sunk by merchant ship guns) 53 to unknown causes Interesting in that one needs to combine the sunk by bombing in port with sunk by a/c at sea to exceed the number sunk by ships alone. Personally I had thought that a/c sinkings exceeded ship sinkings of UBoats by a substantial margin. Oops; didn't read to bottom of page: 32 more lost: 25 to accidents or friendly fire 4 taken over by Japan after German surrender 2 interned by Spain 1 sunk by SOVIET SHORE BATTERIES How have you managed to go from "a single DC should inflict fatal damage" to "all subs lost to surface ships were killed by DCs" as a meaningful position? Those same surface ships used guns, ahead throwing weapons and DCs, and note that DC patters of small numbers were so ineffective that huge patterns became the norm for the Allies. IF DCs were normal - a Japanese PC with a pattern of 3 would be a nice ASW vessel. It ain't.

spence -> RE: damagelethality of depth charges (7/1/2006 6:52:23 PM)
In WitP there are "hits" a la combat report which seemingly cause cumulative damage and there are "hits" in the animation which seemingly show explosions on or immediately adjacent to the submarine. One of those is should inflict catastrophic damage on the submarine, perhaps not fatal but a 'mission kill' anyways. I do not dispute that it generally took a lot of depth charges thrown into the water to get the one that "hits". WitP does not (to my knowledge) allow escort types to finish off of a submarine which has been damaged by depth charges with gunfire or ramming (or by the crew scuttling a severely damaged boat. Thus for the purposes of the game those "finishes" must be included in the "hits" caused by depth charges or other ASW weapons. Reading throught the UBoat Fates Section at Uboat.net I noticed there did not seem to be any differentiation between killed by a depth charge or killed by a hedgehog. It reports that the first hedgehogs were deployed in 1943 so I think it is safe to say that any uboat reported sunk by surface ships before '43 were killed outright using depth charges or so severely damaged by depth charges that they surfaced and were finished off with gunfire, ramming, torpedoes, or scuttling (all of which for game purposes would have to be included in depth charge hits). The "Fates" section also lists the personnel casualties involved in the loss of each boat. There is a strong correlation between boats lost with relatively light personnel losses and ones that were finished off by something other than depth charges. "Lost with all hands" goes hand in hand with "sunk by depth charges from HMS/HCMS/USS...." Of the Uboats reported sunk by ships (264), 22 were torpedoed by Allied submarines (mostly British). Of the boats reported scuttled a like number reported scuttled were in fact scuttled after depth charge attacks so damaged them that they were unable to either fight, run or hide. So the total of uboats effectively sunk by surface ships stays about the same. And well over a hundred of those Uboats were killed by surface ship depth charges (with the aforementioned game qualifications about scuttling, gunfire etc) before 1943.

spence -> RE: damagelethality of depth charges (7/2/2006 4:54:05 AM)
Some figures from the Pacific: DATA FROM IJN SUB TROMs at COMBINED FLEET IJN subs sunk by surface warship alone (subs forced to the surface by ASW weapon damage and finished off with guns, torpedoes or ramming by the same surface ships are included (since WitP does not model this sequence of events - the number of such incidents is roughly 15 or about 25% of the total with more of the incidents relating to depth charge damage than hedgehog damage): PRINCIPLE ASW WEAPON DEPTH CHARGE - 44 KILLS HEDGEHOG - 19 KILLS MOUSETRAP - 1 KILL There were three additional surface ship kills but the TROM did not specify what sort of weapon delivered the fatal attack. In one case there was no mention of weapons used; in the other 2 both depth charges and hedgehogs were used.

Cmdrcain -> RE: damagelethality of depth charges (7/3/2006 8:52:14 AM)
quote: ORIGINAL: ChezDaJez As far as the Falklands war goes, the Brits made a deliberate decision to attack any suspected submarine contact whether it was verified or not. Chez Wonder how many Large Fish, Dolphins, Whales, Sharks and such were shot.... [:D]

ChezDaJez -> RE: damagelethality of depth charges (7/3/2006 11:30:37 AM)
quote: Wonder how many Large Fish, Dolphins, Whales, Sharks and such were shot.... Well, as someone who once "bombed" a disappearing radar contact (determined to be a whale a short while later) with active sonobuoys, I would say probably quite a few! Torpedo suppository anyone? Chez

el cid again -> RE: damagelethality of depth charges (7/3/2006 12:23:23 PM)
quote: ORIGINAL: spence In WitP there are "hits" a la combat report which seemingly cause cumulative damage and there are "hits" in the animation which seemingly show explosions on or immediately adjacent to the submarine. One of those is should inflict catastrophic damage on the submarine, perhaps not fatal but a 'mission kill' anyways. I do not dispute that it generally took a lot of depth charges thrown into the water to get the one that "hits". WitP does not (to my knowledge) allow escort types to finish off of a submarine which has been damaged by depth charges with gunfire or ramming (or by the crew scuttling a severely damaged boat. Thus for the purposes of the game those "finishes" must be included in the "hits" caused by depth charges or other ASW weapons. Reading throught the UBoat Fates Section at Uboat.net I noticed there did not seem to be any differentiation between killed by a depth charge or killed by a hedgehog. It reports that the first hedgehogs were deployed in 1943 so I think it is safe to say that any uboat reported sunk by surface ships before '43 were killed outright using depth charges or so severely damaged by depth charges that they surfaced and were finished off with gunfire, ramming, torpedoes, or scuttling (all of which for game purposes would have to be included in depth charge hits). The "Fates" section also lists the personnel casualties involved in the loss of each boat. There is a strong correlation between boats lost with relatively light personnel losses and ones that were finished off by something other than depth charges. "Lost with all hands" goes hand in hand with "sunk by depth charges from HMS/HCMS/USS...." Of the Uboats reported sunk by ships (264), 22 were torpedoed by Allied submarines (mostly British). Of the boats reported scuttled a like number reported scuttled were in fact scuttled after depth charge attacks so damaged them that they were unable to either fight, run or hide. So the total of uboats effectively sunk by surface ships stays about the same. And well over a hundred of those Uboats were killed by surface ship depth charges (with the aforementioned game qualifications about scuttling, gunfire etc) before 1943. This is a mixed bag - but it also clearly is a serious attempt at analysis. So I will break it down: 1) Early in the war the German doctrine was to attack on the surface. This is the reason that the Naval Escort Service was created - you were not going to contest a raider or the Graf Spee with a single 5 inch gun - but you were dangerous to a submarine. It is probably not valid to assume that any losses before 1943 were caused by depth charges. U boats were, in that era, more submersable torpedo boats, and even submersable gunboats, than submarines. It is likely a significant number were damaged for taking such risks in range of guns of escorts and auxiliaries and merchants - not to mention planes in cooperation with them. 2) The absolute number of submarines lost to depth charges - whatever it is - and I will stipulate it should be over 100 in the Atlantic campaign alone - does not in itself imply a high lethality for any single depth charge. It remains probable that WITP overstates this lethality - likely by a gross amount. Submarine survivability in WITP is clearly less than history. This is for two causes: it is far to easy to detect them - because (like Donitz U boats) they are surface raiders - but in WITP they NEVER are submarines EVER for detection purposes; and probably DCs are way too lethal. 3) You make a somewhat valid point about no surface action after DC damage. However, on the other side, WITP has subs on the surface when it is suicide - slugging it out with guns when no skipper ever would consider it. I hope you don't see this in RHS - but I had to "trick" the code - and if I am lucky it worked in the sense that statistically this will happen a lot less. [What I did was limit ammo for guns. A Japanese submarine - a big one - carried 17 ROUNDS - not salvos. WITP uses a shot system - and I decided a "shot" in this case means 6 rounds - so an I boat gets 3 shots. Once it has used up these shots, it must engage with torpedoes - so it won't try to use the guns. Some subs get 4 or even 5 shots - if they were gun oriented - but most get 3. This is in line with other WITP code- which does not track every round - just shots of several rounds. How they got such huge values for subs is beyond my kin? But I suspect they wanted subs to be a neusence - not effective - as they explicitly wrote about mine warfare. They KNOW they modeled mines wrong - and do not want to model them right.]

el cid again -> RE: damagelethality of depth charges (7/3/2006 12:30:52 PM)
quote: ORIGINAL: spence Some figures from the Pacific: DATA FROM IJN SUB TROMs at COMBINED FLEET IJN subs sunk by surface warship alone (subs forced to the surface by ASW weapon damage and finished off with guns, torpedoes or ramming by the same surface ships are included (since WitP does not model this sequence of events - the number of such incidents is roughly 15 or about 25% of the total with more of the incidents relating to depth charge damage than hedgehog damage): PRINCIPLE ASW WEAPON DEPTH CHARGE - 44 KILLS HEDGEHOG - 19 KILLS MOUSETRAP - 1 KILL There were three additional surface ship kills but the TROM did not specify what sort of weapon delivered the fatal attack. In one case there was no mention of weapons used; in the other 2 both depth charges and hedgehogs were used. All very interesting - and possibly a crude indicator of the cause of losses. One problem is the total is too high - particularly if you bear in mind airplanes got some and unknown causes got some. But OK - lets conclude that many of those lost were lost to depth charges. That needs to be compared to the number of DC dropped to get the lethality PER ROUND. Better still, the number of patterns - the lethality per pattern - and I would also like to know the size of the patterns that worked? IF we could get the data - you would not be impressed with the kill chance of a DC - even if the target is a real sub and not a whale. It was a crude weapon, for which you usually had to guess a depth setting, and directed by sensors that easily could contain errors greater than a miss distance. Add to that the sub might turn right or left, or reverse, or both, or spring ahead, or stay in place - none of which could be known when the charges were set. Tough problem. A proper ASW attack might last many hours - even a day or two. Underwater a sub cannot go very far - and it can't stay down there forever! Well - it can - and we are trying to make it do just that - but it does not want to stay down forever - so it will try to escape - sooner or later - if it is still alive. Our problem is, even if we kill it, we don't know we did, so we have to hang around in case it is only playing dead.

el cid again -> RE: damagelethality of depth charges (7/3/2006 12:33:54 PM)
quote: ORIGINAL: ChezDaJez quote: Wonder how many Large Fish, Dolphins, Whales, Sharks and such were shot.... Well, as someone who once "bombed" a disappearing radar contact (determined to be a whale a short while later) with active sonobuoys, I would say probably quite a few! Torpedo suppository anyone? Chez It is estimated than on the order of a hundred whales were killed in 1982 - by RN - in a campaign in which the enemy had one effective - one ineffective - one non-operational - and one ancient submarine (unable to submerge but still operating - as a surface transport!).

Terminus -> RE: damagelethality of depth charges (7/3/2006 12:34:40 PM)
Well, better safe than sorry...

Speedysteve -> RE: damagelethality of depth charges (7/3/2006 1:11:47 PM)
Ho on earth did they log the number of whales killed?!? Did someone seriously do this el cid?

Terminus -> RE: damagelethality of depth charges (7/3/2006 1:18:16 PM)
They probably didn't...

spence -> RE: damagelethality of depth charges (7/3/2006 4:35:57 PM)
Should anyone be interested the total number of attacks delivered with whichever ASW weapon is noted in the TROMs for the IJN subs. Going through them was a wee bit tedious but my impression is that hedgehogs killed subs with fewer though in most cases multiple attacks. I recall only a relative few where a single salvo/pattern of either hedgehogs or depth charges did the trick (2 for depth charges I believe). What needs to be addressed is the "effect" of the ASW routines. The Japanese Player is given the chance to change history by instituting convoys and forming ASW groups right from the start. Thus Allied submarine losses are likely to be higher in any PBEM game or Allied AI game. Thus really the only "measuring stick" would be the historical effectiveness of Allied ASW efforts in the game which are as follows re sub kills: 1941 - 1 (by Enterprise SBD a few days after PH), 1 also was lost in a collision with another sub, the sub that collided with the sunken sub was heavily damaged as well and returned to Kwajalein where it suffered more damage in the February 42 raid and was never operational after that. 1942 - 14 (does not include the accidental one mentioned above) 1943 - 26 1944 - 50 1945 - 28* Accidental losses (6) ARE included in the totals above: Other than the collision mentioned above, the Japanese seemed to have had a problem remembering to close the main induction valve when diving - the cause of the other five losses. One of those instances was sort of the result of Allied action: a sub in port at Attu or Kiska dove to avoid an air raid but sank because the valve was open. Unknown causes (10) and losses to mines (2 for sure (?)) are also included though there may be some overlap between the former and the latter cause. *The drop in losses for 1945 is probably mostly due to a relative paucity of targets for Allied ASW. Kaitens destroyed in '44 and '45 are not included - all losses are I or RO boats.

rtrapasso -> RE: damagelethality of depth charges (7/3/2006 4:36:37 PM)
i suspect some marine biologists/scientists estimated the numbers on before and after surveys of whale populations in the area, which are pretty carefully monitored worldwide.

spence -> RE: damagelethality of depth charges (7/3/2006 4:45:59 PM)
The German raider Pinguin took out practically the whole Norwegian whaling fleet in 1941 or early 42. That surely helped whale populations rebound. I also suspect that studies of whale populations were pretty shoddy (oriented towards exploitation for sure) or non-existant before WWII. It was quite some time after WWII that any treaties or legislation bubbled to the forefront. I wouldn't be surprised if much of the data that precipitated the laws/treaties actually originated with military studies whose purpose was to avoid "wasting costly ammo" on marine mammals, fish, plankton and so forth.

spence -> RE: damagelethality of depth charges (7/3/2006 5:09:08 PM)
Just for comparision IJN sub kills by year...(don't bet the farm on the figures/causes for Dutch and British subs. Accidental losses not included. 1941 - 1 US (bombed in Cavite), 4 Dutch (2 to mines I think) 1942 - 3 US, 3 Dutch (scuttled in port) 1943 - 16 US 1944 - 14 US 1945 - 8 US, 3 UK (2 to mines I think)

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