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 (SUBmarine ROCket). It was taken out of service in 1989.
Ya think?
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.
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
(Heh. I respect both historians. I wonder which is right.)
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.
Some of the high points have been touched on, but my US$0.02:
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.
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.
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.
Tranq
Qualified in Submarines
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.
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.
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.
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.
“Sir, off the port bow.”
“What is it, Lt.?”
“Bunch of dolphins, sir. They’re trying to surrender…”
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.