(Crack Comics 001-020, 1940-1942)
The Red Torpedo is Jim Lockhart, a guy who came up with a design for the ultimate one-man submarine and turned that into his whole personality. This is a not-uncommon Golden-Age comics trope that kind of petered out once the world was no longer awash with mechanized combat – Silver Age super-vehicles tended more toward the exploration side of things.
So: Jim Lockhart, young US Navy officer resigns his commission after being told that his submarine design was unworkable. He builds it anyway, with the help of his fiancĂ©, Meg, then seemingly leaves her behind as well – a “Peggy” show up as his assistant a few issues later but after that he’s a strictly one-man operation.
Lockhart shows up here and there in the extended DCU – most notably in a Roy Thomas engineered cull of the old Quality Comics characters in All-Star Squadron back in the day. Like most of the others killed off in that ish, Red Torpedo got better and shows up whenever someone needs a really good submarine for something.
Good luck finding it but the thing that really cemented my love for this guy is the Crack Comics installment of the Next Issue Project. A really lovely, simple, melancholy story about a submarine man.