Found out by accident how to resupply torpedos. When you start your next patrol in the admirals office you will see a submarine model on his desk. Click on it and it will take you to a screen which shows torpedos on the left side. (You might have to click on a picture of torpedos on the upper right screen to get there. Once you get to the torpedos just drag each one to its place in the tubes and in reserve. You'll see MK 10 and Mk 14 torpedoes. I think you can only use the Mk 10's with the S boats and the Mk 14's with the other boats. I had the same problem myself and went on a Luzon straits patrol with only 2 fish. (very much red faced). Hope that answers your question
