The weapon is the famous (or infamous) Russian VA-111 Shkval rocket torpedo and its variants, capable of speeds of more than 200 knots underwater. This speed is achieved by the rocket pushing the sharply tapering, flat-tipped torpedo so fast that a vacuum bubble forms around the body of the weapon, greatly reducing water resistance -- the process, for the uninitiated, is called supercavitation.
hardly a wwII torpedo... did you guys see, in a config somewhere, that theere was already a slot for a "missile submarine" ? so next you'll get the cold war game, AND the torpedo pictured above, which was sold to china btw....
more info :
http://www.military.com/soldiertech/...hkval,,00.html