Originally Posted by Randomizer

The book Type VII U-Boats by Robert Stern states that physical changes were required to both the attack computer and torpedo tube to accommodate FaT's. Further modifications were needed to use LuT's and by July 1944 some fifty boats had been refitted for them. The implication seems to be that the modifications were exclusive and a LuT boat could not necessarily launch FaT's or vice versa.

SH3 allows you to use both types interchangably and I have had good success using them against convoys late in the war and avoiding counter-attacks.