You use a special Uboat for those, I forgot what is called though. To use them simply be moving at like, 2 knots, and then fire them away. I set mine to contact, and the depth matters on what your trying to sink. By default I just set them as high as possible. Its really awsome when you plant a field infront of a task force, and watching it get blown to nothing while the destroys enter a panic as they cant find you
