The loss of a South Korean corvette to a torpedo had highlighted the vulnerability of surface ships to this threat. On the night of 26 March 2010 a large explosion blew off the stern of the Republic of Korea Navy corvette Chon An in waters just off the southwest coast of Baengnyeong Island in the Yellow Sea (West Sea). There was no warning and the ship sank in minutes; 46 out of the 104 crew perished.