# Depth Charging Submarines **URL:** \ **Category:** Factual Questions\ **Created:** [September 24, 2009, 2:19pm UTC](https://boards.straightdope.com/t/depth-charging-submarines/511370 "2009-09-24T14:19:35Z")\ **Posts on this page:** 12\ **Page:** 3
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [October 2, 2009, 5:42pm UTC](https://boards.straightdope.com/t/depth-charging-submarines/511370/41 "2009-10-02T17:42:08Z")
> [@AK84](#): > > Did’nt British Ships carry an atomic depth charge in the cold war? How the hell are you supposed to survive that _yourself_ nev er mind the sub? > [@butler1850](#): > > Well, it’d be a fairly small nuke, and exploding at some depth under water. I’d think that the time from drop, through sinking to depth, would allow sufficient time for the plane to escape the blast danger radius. The proviso, of course, would be that the aircraft was hardened against any EMP that may be released, and extend above the water (does an underwater nuclear explosion create an EMP above the surface of the water for any significant distance?). > > The planes that dropped on Hiroshima, and Nagasaki escaped fairly well, and those aircraft were certainly not built to the standards of modern aircraft. **AK84** wasn’t talking about a plane; he was referring to a ship. Aircraft travel far faster than a ship. The Soviets were reported to have a submarine-launched nuclear-tipped torpedo with the same problem as a ship-launched nuclear depth charge: i.e. how do you get out of range of your own weapon? To address this problem, the U.S. Navy developed a submarine-launched stand-off nuclear depth charge called [SUBROC](http://en.wikipedia.org/wiki/UUM-44_SUBROC) (SUBmarine ROCket). It was taken out of service in 1989. ---
**Author:** ![Earl\_Snake-Hips\_Tucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/earl_snake-hips_tucker/32/3269_2.png) [@Earl\_Snake-Hips\_Tucker](https://boards.straightdope.com/u/Earl_Snake-Hips_Tucker)\ **Post date:** [October 2, 2009, 6:12pm UTC](https://boards.straightdope.com/t/depth-charging-submarines/511370/42 "2009-10-02T18:12:20Z")
[QUOTE=SUBROC wiki] A direct hit was not necessary. [/QUOTE] Ya think? ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [October 2, 2009, 6:24pm UTC](https://boards.straightdope.com/t/depth-charging-submarines/511370/43 "2009-10-02T18:24:04Z")
> [@butler1850](#): > > The planes that dropped on Hiroshima, and Nagasaki escaped fairly well, and those aircraft were certainly not built to the standards of modern aircraft. Actually, they were built tougher, as far as withstanding a nearby nuclear explosion. They didn’t have all the fancy electronic equipment that could be disrupted by the electro-magnetic pulse of such an explosion. ---
**Author:** ![mlees](https://avatars.discourse-cdn.com/v4/letter/m/ba8739/32.png) [@mlees](https://boards.straightdope.com/u/mlees)\ **Post date:** [October 2, 2009, 7:04pm UTC](https://boards.straightdope.com/t/depth-charging-submarines/511370/44 "2009-10-02T19:04:31Z")
One of the problems that the Japanese were dealing with was that their pre-war ASW tactics and training lagged quite a bit. The Japanese War planning sections focused mainly on how to kill US BB’s. Much planning and training exercises was devoted towards the “Decisive Battle”. Convoy organisation, Army-Navy cooperation, and ASW tactics were nowhere near as glamorous. Destroyer captains trained hard in night action gunnery and anti-surface-ship torpedo attacks (the duties a screening vessel of the Battle Line might be expected to perform). Training in ASW and convoy screening was not emphasized. * * * In regards to IJN Depth Charge settings, see here: [Andrew J. May - Wikipedia](http://en.wikipedia.org/wiki/Andrew_Jackson_May) > [@wiki](#): > > Historian Clay Blair claimed that May was responsible for a major release of highly confidential military information during World War II, known as the May Incident. In that incident, U.S. submarines had been conducting a successful undersea war against Japanese shipping during World War II, frequently escaping Japanese anti-submarine depth charge attacks. However, the deficiencies of Japanese depth-charge tactics were revealed in a press conference held in June 1943 by Congressman May on his return from a war zone junket. At this press conference, May revealed the highly sensitive fact that American submarines had a high survival rate because Japanese depth charges were typically fuzed to explode at too shallow a depth. Various press associations sent this leaked news story over their wires and many newspapers (including one in Honolulu, Hawaii), published it. > > Japanese naval forces heard of May’s security breach and adjusted their depth charges to explode at a more effective depth. Vice Admiral Charles A. Lockwood, commander of the U.S. submarine fleet in the Pacific, later estimated that May’s security breach cost the United States Navy as many as ten submarines and 800 crewmen killed in action. > > Other historians [Norman Friedman] claim that the May Incident never happened, and that the Japanese never discovered U.S. submarine depth capabilities during the war. (Heh. I respect both historians. I wonder which is right.) ---
**Author:** ![AK84](https://avatars.discourse-cdn.com/v4/letter/a/85e7bf/32.png) [@AK84](https://boards.straightdope.com/u/AK84)\ **Post date:** [October 3, 2009, 6:09am UTC](https://boards.straightdope.com/t/depth-charging-submarines/511370/45 "2009-10-03T06:09:45Z")
The later I think. I would say that the Japanese were smart enough to deduce (after a US sub escaped for the umpteenth time by diving deep) that their charges were set too shallow. ---
**Author:** ![Tranquilis](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tranquilis/32/3639_2.png) [@Tranquilis](https://boards.straightdope.com/u/Tranquilis)\ **Post date:** [October 3, 2009, 6:38am UTC](https://boards.straightdope.com/t/depth-charging-submarines/511370/46 "2009-10-03T06:38:42Z")
Some of the high points have been touched on, but my US$0.02: > [@Chickenwrangler](#): > > In all the movies I’ve seen every time a submarine comes under attack the standard procedure is to go as deep as possible. That’s in movies. Hollywood =! reality. In reality, you go to whichever depth is most favorable for evasion - depends on where the thermoclines are, how deep you can go where you happen to be, your test depth, known enemy doctrine, best estimate of enemy operational intentions/pressures, observed enemy tactics, and how big your balls are. If you don’t know where the thermoclines are, going deeper still gives you a better chance of having one above you, though it’s no guarantee. Deeper also means that it takes longer for a charge to reach you, giving more time for evasion or simply random irregularities in the descent behavior of the charge to carry it away from you. > [@](#): > > I can understand that a deep sub may be harder to detect but the deeper it goes the grater the pressure on the hull. Depth charges, as I understand it, work by the pressure blast they create to shatter the sub. Yup, but test depth =! crush depth. There’s a large margin built into the boats - You have to get real damn close to crack a hull with a depth charge. _Far_ more lethal are the kinds of plant casualties you get from continual pounding by heavy shockwaves - equipment coming off mounts, brackets warping and failing, cable connections coming adrift, pipe welds breaking, bolts shearing… The skimmers aren’t counting on a haymaker direct hit; They’re planning on beating you to death, slowly but surely. > [@](#): > > If a sub is at great depth say near it’s pressure limit it would need just a tiny extra bit of pressure, from a depth charge, to rupture it. As above, not really. Even when you exceed test depth, there’s a substantial margin. There are plenty cases of WWII boats coming back with their pressure hulls bowed and warped from extreme depths beyond test depth, and having still survived heavy depth charging at those depths. **AK84** : US warships also had recourse to rocket-delivered nuclear depth charges: [AN/UUM-44 SUBROC](http://en.wikipedia.org/wiki/UUM-44_SUBROC). Tranq Qualified in Submarines ---
**Author:** ![casdave](https://avatars.discourse-cdn.com/v4/letter/c/c6cbf5/32.png) [@casdave](https://boards.straightdope.com/u/casdave)\ **Post date:** [October 3, 2009, 9:08am UTC](https://boards.straightdope.com/t/depth-charging-submarines/511370/47 "2009-10-03T09:08:22Z")
Ref the atomic depth charge. It is not at all unusual for RN vessels to carry one, or rather to carry something that may, or may not be such a device - the crew will not be informed which is which so they have to treat them as the real thing, though of course the CO will know. They used to be a substantial percentage of maximum load for the Westland Waps helicopter, which wasn’t a particularly powerful machine. I could not imagine on of those being able to clear itself fom the blast zone, but then I don’t know what the deployment details were, it could be dropped from very high up and slwoed by a chute, but that is just speculation. The more recent helicopters probaly would be able to clear the zone. ---
**Author:** ![Tranquilis](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tranquilis/32/3639_2.png) [@Tranquilis](https://boards.straightdope.com/u/Tranquilis)\ **Post date:** [October 3, 2009, 2:30pm UTC](https://boards.straightdope.com/t/depth-charging-submarines/511370/48 "2009-10-03T14:30:08Z")
> [@casdave](#): > > They used to be a substantial percentage of maximum load for the Westland Waps helicopter, which wasn’t a particularly powerful machine. > > I could not imagine on of those being able to clear itself fom the blast zone, but then I don’t know what the deployment details were, it could be dropped from very high up and slwoed by a chute, but that is just speculation. Well, they wouldn’t be dropping from a hover, I’m fairly sure. Nuclear warheads don’t need a precision drop to score a kill. 😉 But even if they were, a few hundred feet of water is pretty good tamping. Anyway, I suspect the UK weapons didn’t have a particularly large warhead. The SUBROC used a W55 warhead, variously thought to have yields of 1, 5, or 250 KT. Kill radius is given as 8km (in water). Surface effect would be considerably reduced by the tamping effect. If a helo made a high-altitude, high-speed pass, and got the warhead in the right general area - That’d be enough. A pretty rough ride, I’m sure, but not precisely suicide. Still, you can see why everyone prefers homing torpedoes these days. ---
**Author:** ![Chickenwrangler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chickenwrangler/32/91_2.png) [@Chickenwrangler](https://boards.straightdope.com/u/Chickenwrangler)\ **Post date:** [October 4, 2009, 2:38am UTC](https://boards.straightdope.com/t/depth-charging-submarines/511370/49 "2009-10-04T02:38:51Z")
Just as a small side issue. All that depth charging going on in the Atlantic during WWII must have killed a lot of fish. Did this affect the fishing industry? I assume fishing boats would sill have to have been operating especially as Britain was being “starved into submission” . Or did all the fishing boats stay in harbor for fear of being targeted by the Germans thereby adding to the general food shortage. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [October 4, 2009, 3:57am UTC](https://boards.straightdope.com/t/depth-charging-submarines/511370/50 "2009-10-04T03:57:46Z")
> [@Chickenwrangler](#): > > Just as a small side issue. All that depth charging going on in the Atlantic during WWII must have killed a lot of fish. Did this affect the fishing industry? Most commercial fishing happens near shore – within a couple hundred miles of a shoreline or island. Most submarine attacks took place far out in the middle of the ocean, where the submarines were out of reach of aircraft. So these areas didn’t overlap that much. ---
**Author:** ![elucidator](https://avatars.discourse-cdn.com/v4/letter/e/8edcca/32.png) [@elucidator](https://boards.straightdope.com/u/elucidator)\ **Post date:** [October 4, 2009, 4:40am UTC](https://boards.straightdope.com/t/depth-charging-submarines/511370/51 "2009-10-04T04:40:09Z")
“Sir, off the port bow.” “What is it, Lt.?” “Bunch of dolphins, sir. They’re trying to surrender…” ---
**Author:** ![Tranquilis](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tranquilis/32/3639_2.png) [@Tranquilis](https://boards.straightdope.com/u/Tranquilis)\ **Post date:** [October 4, 2009, 2:30pm UTC](https://boards.straightdope.com/t/depth-charging-submarines/511370/52 "2009-10-04T14:30:45Z")
> [@t-bonham@scc.net](#): > > Most submarine attacks took place far out in the middle of the ocean, where the submarines were out of reach of aircraft. Um, not really. A LOT of attacks happened right off the US Atlantic coast. Also, a lot of attacks just off the UK and European coasts, too. North Carolina’s Outer Banks aren’t called ‘The Graveyard of the Atlantic’ for nothing! But in a straight-up answer to the fisheries question: The ocean is a BIG place. Depth charges are small. Fish are mobile. The first few charges in any attack might have caught a few fish, but after that, the local are would become pretty much devoid of all fish as they decamped en mass and at speed for friendlier locals. [Previous page](https://boards.straightdope.com/t/depth-charging-submarines/511370.md?page=2)