They did use them. I've seen pics and film of them doing so. It was quite an operation: They erected a winch over the deck hatch for the stern or bow compartment, retrieved the torpedo from the deck cannister, attached life vests to them in order to increase their buoyancy and floated them to the winch, assisted by running the boat decks awash. In order to retrieve them, the sub would withdraw to a quiet area, which became problematic as the war progressed. By the latter stages of the war, wherein the Allies covered just about every square inch of the ocean with planes and hunters, it was rare for a U-boat to be in the position of having fired off all of its internal torpedoes. Unfortunately, the game's engine does not simulate this in a realistic fashion, at all! For example, if you dive while reloading an external torpedo, all the game does is suspend the activity. When you surface, the countdown resumes from where it was halted. In real life? The sub was very vulnerable to attack; at best, the torpedo was cut adrift. At worst, the sub was lost. Still, I cannot recall having read many accounts, if any, of a U-boat being lost only because it was caught in the act of reloading an external torpedo. The operation was usually done in a quiet area, often at night before the Allies deployed airborne radars. The practical usage of external torpedoes closely paralled the use of the deck gun. If it was safe enough to use a deck gun, it was safe enough to use an external torpedo, and vice versa.
As mentioned earlier, I restrict myself to a more realistic handling of external torpedoes. I withdraw from a convoy if I am in contact, stop or run the boat very slowly in a calm or near calm sea and then reload it. To judge whether it is feasible to reload, I observe the boat from external viewpoint. If the seas are breaking over the deck, I do not reload. If I am jumped, I simulate several minutes of "cutting away the torpedo and abandoning the deck winch." Then I crash dive and make a note that the relevant torpedo is now "lost."
__________________
|