I’m watching a ton of WW2 documentaries and can’t help but think why they didn’t make a counter to the German Uboats other then depth charges and the hedgehog. Surely with the money and resources the US or other countries could of made a sub during that time.
In: 12
One nuance not really mentioned yet is that submerged submarines of the time were much slower than surface ships.
To sink a submarine, first you have to find it, then chase it down, then cause enough concussive force in the water to break it up. In World War II, the allies used aircraft and their fastest surface ships (destroyers) to do the finding and chasing. Looking down from a couple of miles (and eventually using radar), the aircraft had a better chance of spotting the U boats than another submarine whose search would be limited by its slow speed. The fast destroyers then could do the chasing and bombing (though some aircraft could drop a couple of charges) while the aircraft kept the quarry in view.
The strategy of the U-boat was to sail on the surface toward an area where a convoy of enemy ships could be expected. Then the U-boat would submerge and lay in wait until a target was in range, take one shot, and run like hell. But “like hell” was about 1/3 the speed of the American destroyers! So they were really relying on stealth and hoping to get away through a combination of hiding underwater and speeding away on the surface when no one was looking.
Out of curiosity what docs are you watching?
Others have well covered the sub v sub history, so let me cover some details.
WWII [Liberty ship](https://en.wikipedia.org/wiki/Liberty_ship) – 441 Ft / 136 M long, 27 Ft / 8.5 M draft
WWII [Balao class](https://en.wikipedia.org/wiki/Balao-class_submarine) sub (USA) – 331 Ft / 101 M long, 27 Ft / 8.5 M draft
Note the Liberty ship would cruise at 10 Kt (convoy) which means it moves it own length every 26 seconds. The Balao could move about half that speed submerged (8 Kt emergency, usually 5 or less), so 20 seconds to move it’s own length at 5 Kt.
Combat: The surface ship is a 30 foot high x 400 foot long target as seen from torpedo view. Set the weapon to 20 feet and fire. Unless it changes course, you win. The USA [Mk 14 Torpedo](https://en.wikipedia.org/wiki/Mark_14_torpedo) (similar numbers for German) moved at 31 or 46 Kt for long/short attacks out to 9000/4500 yards. This meant a run of roughly 600 or 195 seconds at maximum. A long attack vs a Liberty ship means 23 ship lengths, short 7.5. Lots of things can go wrong. Plus, you are moving well into the gun range of escort destroyers and similar.
Now combat vs sub: Similar numbers, but only if the target is surfaced. If it dives, the Balao now has 20 feet or more or water over the deck, so the torpedo would pass right over unless it hit the conning tower — less than 10% of the overall length. So the problem for sub v sub is where to aim and how deep.
The allies absolutely demolished the U Boats, they couldn’t have made an even better counter than they already had
In the second world war submarines had to operate most of the time on the surface, in order to run internal combustion engines that powered them and recharged the batteries.
The batteries could power the submarine for brief underwater operations, at relatively slow speeds.
To counter submarines it was necessary to first find them. The best ways to do that at the time was radar, detecting the metal hull of the submarine when it was above the water, or visually, by spotting the surfaced sub. Sonar could detect a submerged submarine at short range (at most a few miles).
So the best way to find and kill subs was flying over them. Detecting them with radar or seeing them from above, then radioing surface ships to go there and help kill the submarine. Even if they diden’t get the sub, this was a very effective way to drive it off.
A submerged sub could have sonar, and perhaps detect another submarine at a range of a few miles, but couldn’t get radio transmissions from aircraft to coordinate a hunt or call them back without surfacing, sort of putting them in the same boat* as a surface ship that is cheaper because it’s not made to go under water.
A sub-hunting submarine is more a modern thing, based on modern subs being designed to spend almost all time under water.
*I’m very sorry about this pun.
… We DID use submarines. But Subs were not used to hunt other subs until during the Cold War, and even then instead of sinking it was tail the enemy sub.
Also, WWII subs SUCKED. Couldn’t stay down for long, had VERY small number of torpedoes, and had a very low submerged speed, and a only SLIGHTLY better surface speed.
USA especially during WWII had DOZENS of submarines, we just mainly had then in the Pacific to sink Japanese ships because that was the large naval threat. German U-boats were only a threat to shipping, and that was mitigated by destroyers and armed convey ships
During WW2, torpedoes were not guided. They just went in a straight line. The sub would have to determine the range, speed, and direction of the enemy ship they intended to sink and calculate a firing solution. That’s a lot easier when you don’t have to worry about the targets depth as well. And when they can’t change depth.
Also, the common tactic was to bracket the enemy sub and prevent them from escaping. Back in WW2 subs could only stay under water for a limited amount of time before they’d have to surface again. It was easier and more cost effective to hunt sub with surface ships vs other subs.
The US did have a lot of submarines in WWII. They mostly used them to go after surface ships and to secretly transport Marine Raiders to occupied islands. (Gung Ho!)
Submarines aren’t very good at destroying other submarines. Destroyers with active sonar and depth charges did a good job at hitting submerged ones, and heavy attack aircraft with searchlights early in the war and radar later were good at hitting surfaced ones. And during WWII a submarine couldn’t stay submerged very long. They mostly traveled on the surface and submerged when they needed to hide.
German U boats were used to sink surface ships. British/US surface fleets could already sink any German surface ships. Why build new submarines to do the same thing?
As even any HOI4 player will tell you, submarines are bad at destroying submarines. Hunting them with destroyers was just far, far easier to do.
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