Hull difference....german, american

[Palidian]

However if the hull is close to being round, size should not matter. Try smashing an egg with your hand.

http://www.wonderquest.com/egg-pressure.htm

Originally Posted by Penelope_Grey

Semi-True, however the Gato has a larger surface area, therefore the total area of pressure is greater than that of a U-Boat. as in.... Pressure per square inch is the same, but a Gato has a lot more inches than a U-Boat does. So will naturally not be able to go as deep due to being larger.