Not sure about WW2 but I think they used seperate fuels for steam and diesel.

These days NATO uses F-76 (or variants of F-76) which is used by Steam/Gas Turbine and Diesel warships.

Ships carrying aircraft have JP-5 (or variants of JP-5) for the aircraft. JP-5 can also be used by the Steam/Gas Turbine or Diesel engines but is usually not because its more expensive. If a ship refuels from a CVN it will get JP-5 since the carrier does not have F-76

Here is a link to a article about fuel oil

Combined Diesel or Gas is Diesel and Gas Turbine and both can use F-76 or less likely JP-5. There is no gas as in gasoline on board most USN ships and if there is then there is very high standards for stowage, either in special cofferdam tanks and sparkless pumps and ventilation or in small quantity rigged in barrels to be dumped over the side since gasoline fumes are very explosive.

Last Edited By: hoist40 Apr 15 16 10:09 PM. Edited 1 time.