I made a post about this before..
Every Sub book I read, well the two ( Combat Patrol and Submarine ) almost "ALL" night attacks ( and they would shadow a convoy until it was night usually ) was almost all on the surface, I mean they would get as close as 1000 yards and fire a salvo and not get caught, fire 3,3, and then spin around and fire their rear torps.. 3 different ships, "THEN" they would usually just run away, or dive and run that way..
Its weird if you think about it, in one chapter of one of the books they talked about how a submarine was really a surface ship attaker but had the option to dive to avoid getting killed..
They also had ice cream machines on many Gato class subs