The destroyers had to set the depth that the ashcans exploded; still, they had to pass directly over the sub that they were hunting. It seems ridiculously easy for the sub down below to simply release buoyant explosives to create an instant minefield.
Why didn’t this happen?
Carrying space inside a sub. Where will you put dozens to hundreds of explosives and buoyancy stuff?
Plus, I doubt the “mines” would be powerful enough.
The submarine really wouldn’t like being underneath an exploding mine. It would have to scoot off quite fast and the Destroyers would track that quite easily and they were much faster.
The submarines’ best strategy was to stop and try and hide near the sea-bed.
A submarine was good at delivering a single motorised explosive charge to where it would have the most effect. If the sub-hunters could have responded in kind then they would have. Instead, the best they could do was drop a big bang on a proximity fuse and hope it would be near enough to do some damage - not because this was a particularly effective method but because there wasn’t a better one.
Because the space for offensive weaponry was better filled up with torpedos.
So, the submarine has to be directly in the path of the destroyer. If the destroyer is even a few meters to port or starboard, the mine is going to pop to the surface indicating exactly where the sub had been some number of seconds earlier. Then the submariner has to exactly calculate the speed of ascent for the mine from his position to the surface as well as the exact time that the destroyer will arrive directly above him. (Issues: Is buoyancy affected by water temperature and how many temperature changes occur between the sub’s current depth and the surface. Are there currents in the water at different depths that may cause the mine to drift out of line from the oncoming destroyer? Is the destroyer following a straight or curved path? Is the destroyer maintaining or changing speed. How accurate is the sub’s ability to actually determine that speed?)
Actually, this is not accurate. A depth charge, like a hand grenade, is not a direct contact weapon. The pressure created by the explosion could seriously damage or even sink a submarine from many meters away.* This is why the K-Gun and earlier Y-Gun projectors were developed: they hurled the depth charges many meters off to the side to account for the sub not being directly below the destroyer.
The sub has to get that close and risks being depth charged.
They actually stayed some distance away and sent in torpedoes . Athough a safer range for the sub, the ship had no such safety, the range left no escape for the ship…
Didn’t they fire torpedoes from close to the surface? Like, periscope depth? If so, I’d imagine a destroyer would have better weapons to use than depth charges…
When we fired A/S mortars, each bomb being 400lbs of bang, they had a range of around 1000 yards, and when they exploded you could feel the ship kick good and proper
I’d hate to have been underwater even at that range - the shockwave would be far worse, and anything under 100 yards of going to be extremely unpleasant - I’d expect at least some minor damage to a sub, and at 50 yards I’d expect some far more serious damage - lets face it, if you were in open air 50 yards from three 400 pound bombs going off, you’d notice - if you survived - underwater you would get an even bigger shockwave.
Also once a sub is on the defense (even today) it’s best weapon to is remain undetectable. Releasing offensive weapons would instantly give away its exact location. Also, subs are not armored in any way like surface warships are. Therefore a sub’s offensive weapons (which in WWII were always for surface vessels) have to be much more powerful than the weapons used to attack it.
Besides the reasons already provided (space being a big one - WW2 submarines would already leave port with crates of food packed everyfuckwhere, including the showers and the head) : because then the submarine would be broadcasting his exact position far and wide. This sounds bad when one’s defense mechanism is “hide until they give up”.
FWIW, modern accoustic countermeasures (of the kind seen in Hunt for Red October) are something of a last resort, for the exact same reason. Doesn’t matter if they helped you spoof one torpedo : the other guys now know for sure there was something there for their torpedo to hit.
Besides, depth charges were usually more of a desperation solution than anything else anyway. Towards the end of the war they’d gotten better (as if German skippers needed any more aggravation), but when the operative principle behind your weapons system is “throw enough shit at the wall, hope some of it might stick”, you’ve basically given up.
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They actually stayed some distance away and sent in torpedoes .
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Well, if you call “~1.000 feet, closer if at all feasible” some distance away. Torpedoes were unguided (for the most part) so the furthest you got, the more the approximations in your trig - distance, speed of target, ownspeed, angle on the bow etc… would have a chance to show. And of course, the more time the target had to notice the wake or randomly change course and speed as was the doctrine when subs were reported in a sector.
TL;DR : sub skippers went for the throat. Which may or may not have contributed to the 13% survival rate among German U-boot crews.
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Didn’t they fire torpedoes from close to the surface? Like, periscope depth? If so, I’d imagine a destroyer would have better weapons to use than depth charges…
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They often did surface attacks at night actually. WW2 submarines had abysmal underwater performance - crap speed, crap acceleration, crap endurance… To give you an idea, a Type VII U-boot could do 7, maybe 9 knots submerged. Your average freight liner tooled around at 15. A warship could cruise in the high 30s. So unless the submarine had both a hell of a head start and/or advanced knowledge of their target’s course and speed, thus be able to race ahead and lie in wait, they had to chase on the surface and trust in their low visibility to remain unnoticed.
WW2 subs really have to be understood as “surface boat that can submerge”, not “underwater boat that could conceivably come up” like modern subs are.
I’m guessing “~1.000” means “about a thousand?”
To a Yankee, that looks like “about one point zero zero zero.”
The average depth of the ocean is somewhere between 12,000 to 14,000 feet deep. In general, submarines, then and now, do NOT “try and hide near the sea-bed.” Even if you were in relatively shallow water, that seems like an excellent way to clog up all of your cooling seawater intakes.
Submarines also didn’t (and don’t) stop, in general. That just leaves you as a sitting duck, waiting for a destroyer to triangulate your position. It’s much more difficult to determine the position of a moving target, especially if it changes course at random intervals. Instead, the sub would attempt to stealthily get away.
Near the end of WWII the us developed an small acoustic torpedo, I can not remember its name. It could be shot off below 60 feet. The Idea was as a destroyer began its high speed run the shot was taken. The torpedo would home in on the rushing destroyer.
Depth charges are probably more effective against a submerged vessel that is already ‘using up’ some of its designed capacity to resist pressure than they would be against ships floating on the surface, where the shock wave can dissipate by disrupting the surface.
I think you’d have to score more or less a direct hit with an ascending depth charge, whereas with a sinking one, you just have to get close enough for the shock wave to harm the sub.
Well, but to look at it another way, a sub’s hull is already designed to resist deep pressure whereas a surface boat’s isn’t - so a nearby underwater explosion would also need only be “close enough” for the extra pressure to exceed design capability. The other objections in this thread are already more than enough, though.
Right :). I always get tripped up by that one (in French it’s the other way round, comma for decimals and full stop for separation)
At the start of the war they had to pass over the sub, but by mid-war they were firing them off to the side off a launcher.
Later still there was an even deadlier anti-sub weapon called the hedgehog. This fired a pattern of 24 small charges ahead of the ship, as it approached the sub. This had a couple of really big advantages. One was that unless one actually actually hit the sub, it wouldn’t explode at all. That meant the water didn’t get all roiled up and they could continue tracking the sub before and after firing. And if there was direct contact only a very small charge and small hole in the sub was needed to sink it.
Here’s a video of how the hedgehog worked.
Generally true, but the depth change has to explode really close to the sub to do damage. If the explosion was 50 ft. down, they’d be perfectly safe at 150 ft.
Subs were commerce-destroyers during WW2. Their job was typically to sink merchant shipping, not to take on warships mano-a-mano.
Certainly it happened that subs sank warships, but that was not what they were for: and a sub that made it a habit was likely to end up a dead sub.