In the 1950s and 1960s the U.S. Navy developed a multi-product supply ship that could deliver fuel, ammunition and stores while underway. These ships saw the introduction of a transfer system using a ram tensioner that keeps the highline between the ships tensioned, allowing for smooth transfer, as well as taking into account any movement of the ships in the water. Over time this method evolved into the Standard Tensioned Replenishment Alongside Method (STREAM). The STREAM rig is preferred over other connected replenishment methods as it permits a greater separation between the ships.