In actual practice many torp attacks vs ships on the high seas were done at minimal ranges, since the ships were free to manuever. You got in close and released at a few hundred yards out, just long enough for the torp to arm and get going at proper depth. Otherwise the PK was rather low, especially with AAA and maybe fighters around. I doubt too many torp crews were fying nice and straight doing math as the sky erupted in fire and smoke from the shrapnel of the picket ships.
Vs ships in harbor, it was just a matter of a proper release, didnt require any special calcs, ie Taranto, Pearl Harbor, and other raids done vs merchant vessels, ect, and of course Subs had TDCs, which greatly improved the practicality of lining up a target and engaging quickly, that and they had the time and cover to set up attacks, unlike a/c flying in low under fire.
