Since submarines became part of the United States Naval Service in 1900, the United States Submarine Force has lost 65 submarines, and more than 4,027 crewmembers remain on final patrol. Those remembered include losses from 1915 through 1968, from USS F-4 and USS F-1 to USS Thresher and USS Scorpion, spanning accidents and wartime sinkings across the history of the service.