The Navy already is investing in fusion research through the Polywell design. Nuclear reactors on ships are big, heavy maintenance intensive, relatively fragile

The Navy already is investing in fusion research through the Polywell design. Nuclear reactors on ships are big, heavy maintenance intensive, relatively fragile, and require a rather involved port call for refuelling. Any sort of fusion-powered craft would be quite literally floating on its own fuel supply, making it cheaper to operate, safer, and cleaner, which makes the end of life costs for a ship lower.