Not every Navy vessel, just the nuclear-powered ones, which only make up about 40% of the fleet.
Oops, I stand corrected, there’s stt=ill like a dozen oilers left in service. But I still don’t think the total comes to half the fleet. Th rest run on gas turbines.
Sorry, didn’t realize so many ships have switched to gas turbines. But the point stands—any problems with steam have been solved, and if it is sufficient to use in a fleet that has millions of miles traveled, then it should be considered for smaller vehicles.