Placed in service again, "YMS-402" departed New York on 30 October and moved north to the St. Lawrence, whence she proceeded to Buffalo, where she served as a naval reserve training ship until after the outbreak of war in Korea. Named USS "Seagull" and redesignated AMS-55 on 1 September 1947 and recommissioned on 10 May 1950, the former YMS returned to the Atlantic in September 1951 and took up training duties in the 5th Naval district. Initially based at Norfolk, Virginia, and then at the Mine Warfare School, Yorktown, Virginia.