Sounds about right. Only question back then, for the smaller targets, was "torpedo or guns?"
I doubt guys in my generation thought that up. Probably a hand me down from the old boat guys. They lived and died proving it. Wahoo and Trepang are still on patrol.
Sorry not Trepang, the Tang. Commander Richard O’Kane and his lookouts were knocked off the conning tower when their own torpedo circled back on them and sunk the boat off Japan they were picked up by a Japanese destroyer and treated less than favorably. His book Clear The Bridge recounts his experiences. He served on the Wahoo under Mush Morton as exec. It’s good reading. Eugene Sedges book With The Old Breed is good too. US Marines got to know the Japanese soldiers very well.