The Navy first started with using sail for power, but then when fosial fuel was discovered they changed for sail to gasoline. There was one problem with gas, it put of harmful fumes that would get trapt in the submarine and harm the crews lungs. After a while diseal was discovered and the Navy started using diesal fuel instead of gasoline. Diesal doesn't put off the fumes that gasoline does but it still doesn't burn underwater because there's no oxygen for the spark plugs to spark. The Navy stoped using fosial fuel around 1954, in 1954 the Navy set their first Nuclear Submarine to sail.