It sank on a training voyage and killed its crew, then got raised back up and put back into service, then it went out on another training voyage where it sank killing its crew and also its creator, then was put back into service where it blew up a US navy ship, sank and killed it’s crew.

Thing was a marvel, not so much of engineering but of pig-headed determination in the face of every possible sign from the universe telling you to stop.