Underway Replenishment - History

History

Prior to underway replenishment, coaling stations were the only way to refuel ships far from home. This however had two disadvantages: the competition between the colonial powers for suitable sites astride the world's trade routes, and the introduction of a predictable pattern to a nation's naval operations.

Following some early development starting at about 1900 for transferring coal, the technique of underway replenishment was perfected by the United States Navy in the 1920s and 1930s, beginning with the supply ship and receiver ship coming along side each other at full stop in good sea states, but this was found impractical and methods were developed while ships were underway. And these methods developed were used extensively as a logistics support technique in the Pacific theatre of World War II. Since it allowed extended range and striking capability to naval task forces the technique was classified so that enemy nations could not duplicate it. Presently, most underway replenishments for the United States Navy are handled by the Military Sealift Command. It is now used by most, if not all, blue-water navies.

Germany used specialized submarines (so-called milk-cows) to supply hunter U-boats in the Atlantic during World War II. However, these were relatively ponderous, required both submarines to be stationary on the surface, took a long time to transfer stores, and needed to be in radio contact with the replenished boat, all conspiring to make them rather easy targets. Due to this, those not sunk were soon retired from their supply role.

While the United States has invested a great deal of time and effort in perfecting underway replenishment procedures, these are still hazardous operations.