For over half a century, the U.S. has maintained a reserve fleet of older merchant ships (the National Defense Reserve Fleet), to be used in case of a national emergency. Initially, these ships were left over from the thousands produced during World War II. Peak size of this fleet was 2,277 ships in 1950. During the Korean war, 540 ships were mobilized to support military operations, and another 172 were called up during Vietnam. Today, there are 540 ships in this reserve fleet. But 133 of them are awaiting the breakers (being taken apart for scrap metal), 65 are in long term storage and 76 are in the ready reserve fleet (available for moving military cargos on short notice.