[KaleunMarco]

Originally Posted by Hrulj

I’ve been reading a few alt-history timelines dealing with battle of the Atlantic and general idea they go for is to design a subsurface, gunless, schnorkel Walther propulsion submarine with 24” Japanese long lance copy torpedos.

I am by no means an expert but I feel like this design is not really suitable for 1939 (even if it is possible to make it work) and that all it would do is cause earlier development of counter-measures that at the time still don’t exist, to counter the counter measure design for issues that still don’t exist - such as advanced sonars, complete and competent air coverage and more all while giving up on the early war advantage the U-boats had such as “fast” surface movement speed, deck guns that give ability to spare torpedos for more valuable targets at the time when surface ships are still unarmed, and also saves Britain the cost of arming their merchant ships in the first place.

People here are way more knowledgeable than me so I’d ask if you could please, tell me what would be your ideal 3 designs for U-boats meant to act in early - pre 43 and late 43 and onward and criticize my own ideas for it.

Some ideas I’d have is increase the number of torpedo tubes to 6-4, research into posibility of wire-guidance systems for torpedos by slaving the tube/salvo to the periscope, able to adjust their movement underwater to follow the periscope for example. Don’t bother so much with extreme diving depths of early boats and use a simpler easier to produce design. Research into thermal layers, their effects on sonar and produce sensors capable of detecting it.

clone a Balao or Tench class and that is the best of the lot in 1943.
the Germans built some sexy machines late in the war but they little or no action, so one can't really count them as viable.
keep in mind that the famous/infamous IJN Long Lance torpedo was a ship-launched weapon and not a sub-launched weapon. it was almost 30 feet long, 610 mm (vs 533 for sub launched) and weighed 3 tons.
all IJN subs fired a 21 inch/533 mm torpedo(s).

anyway, the Gato/Balao/Tench class was the best of the lot so clone one of those.