In July the U.S. Navy put into service the first of six 22,000-ton T-AO 205 class replenishment oilers (tankers) that refuel warships at sea. The 205 class ships are 227 meters long and operated by a crew of 99 civilian sailors. These ships can be equipped with some defense weapons and systems but are usually unarmed. Each of the 205 class ships cost about $640 million and take about three years to build.
The fleet also has twelve T-AKE type replenishment ships. The 41,000-ton T-AKEs carry cargo and ammunition as part of a larger replenishment fleet required by American warships operating worldwide. There are two additional T-AKEs that transport marine prepositioned equipment so that the marines can just fly in marines to use the vehicles, weapons and equipment aboard the T-AKE.
The navy put four 48,000-ton T-AOE fast (45 kilometers an hour) supply ships into service during the mid-1990s. These were retired because the slower (37 kilometers an hour) T-AKEs and other supply ships got the job done more efficiently and cheaply. This is partly because the United States has access to more overseas ports for resupplying and refueling its carrier task forces.
Modern at-sea replenishment methods were developed out of necessity by the United States during World War II because of a lack of sufficient forward bases in the vast Pacific. The resulting service squadrons (Servrons) became a permanent fixture in the U.S. Navy after the war. Since World War II ships frequently stay at sea for up to six months at a time, being resupplied at sea by a Servron. New technologies were developed to support the effective use of the seagoing supply service. Few other navies have been able to match this capability, mainly because of the expense of the Servron ships and the training required to do at sea replenishment. China is now adopting this capability, which makes their fleet more effective because warships can remain at sea for longer periods. This is especially true for their aircraft carriers, which are not nuclear powered and consume a lot of fuel.