[Sailor Steve]

One of the things that slowed them down in real life is reloading torpedoes. There is a chance of a torpedo breaking free of its hoist if the boat is diving steeply, so they were never reloaded while there was a chance of a counter-attack. They would fire all the tubes and then dive deep, and wait for the destroyers to find them. If they came under attack they would try to escape. If, after awhile, they determined that they were safe they would then reload and resume the attack. This meant having to do an end-around on the convoy and start over again. They couldn't just have the crew keep reloading on the fly while they pummelled the convoy over and over again.