Typhoon

Base stats are not affected by Workshop upgrades neither Officer's skills. Typhoon is the biggest submarine ever added to the game and built in real life. Like all submarines, it has the power to dive, becoming invisible for some period of time, before emerging back to the surface. Because of his length, his top part is always visible over the waterline, not really affecting it's ability and the recharge time is about 10 seconds.

Despite it's length and size, the Typhoon doesn't really become a powerful weapon of destruction until you remodel it to one of the upgraded versions or opt for the Premium version of it.