Maumee-class oiler
The Maumee class was a class of four United States Navy fleet oilers in service from the mid-1950s until the mid-1980s. It was the first class of United States Naval Ships.
The Maumee class ships were the first of the Navy's new "supertankers", significantly larger than previously classes. They also were the first U.S. Navy ships specifically designed and launched with an intention that they be operated in a non-commissioned status by the Military Sea Transportation Service, later the Military Sealift Command, with civilian crews working under contract. They thus became the first United States Naval Ships, and the first to be given the designation "USNS" instead of "USS". The "T" appended to the beginning of their hull numbers indicated civilian manning, a convention still in use today. When the lead unit, USNS Maumee, entered service in December 1956, she was the first USNS ship in history.
The ships were not designed for underway replenishment. Rather they were intended to transport bulk petroleum products, such as fuel oil, gasoline, and aviation fuel, to American military forces overseas. At some time after the loss of USNS Potomac in 1961, the three survivors were reclassified as transport oilers, and were redesignated as such by having an additional "T" appended to their hull code.