sentences:  On the morning of 25 June an armed North Korean steamer (ex US transport of 1000t, taken by South Korean communists to the North in October 1949) tried to disembark about 600 troops 18 miles off Pusan, but it was sighted and sunk by Republic of Korea Navy (ROKN) patrol craft "Bak Du San" ("PC 701").This was the first naval surface action of the war.At the same time North Korean convoy (2 submarine chasers, 1 minesweeper and 20 schooners) started disembarkation of 4 battalions in Kangnung area; another convoy (2 minesweepers, 1 patrol ship, 1 submarine chaser) - disembarkation of communist guerrillas near Samcheok.