I don't think the game cares much. In real life, however, the boat had to be stopped in calm weather. A small tripod with a winch had to be set up. Each torpedo had to be winched out of the external casing and then lowered through the Torpedo Loading Hatch and into the boat. Then the torpedo had to be stowed in the housing cradle in the torpedo room. Each torpedo weighed more than a ton. And all this had to be done while sitting still.
If the boat should be attacked during the process it was helpless. The torpedo might be halfway down the hatch, in which case it couldn't be dumped overboard, and the hatch into the torpedo room was stuck open, so the boat couldn't dive either.
This page has some good photos of how the process worked.
https://forum.axishistory.com/viewtopic.php?t=203947