LARC-V

The LARC-V took the DUKW's job and built it from aluminum, which spares it the rust that eats steel amphibians. It carries 5 tons, or up to 20 passengers, and manages about 7.5 knots in the water and 30 mph on land. The US Army used it extensively for supply over the beach in Vietnam, where about 500 were destroyed, most of them scuttled during the American withdrawal, but the survivors outlasted the war. Navy beachmaster units and the Army Corps of Engineers have kept it in use, the Navy has run a service life extension program for its fleet, and it is still in service with several countries. A cargo amphibian that is still working decades after it was designed is exactly the kind of proof this list looks for.