As in all of America's modern wars, in Korea the U.S. Navy and allied navies had to eliminate the enemy presence at sea before concentrating on the conflict ashore. Soon after the North Korean invasion of June 25, 1950, the Republic of Korea Navy (ROKN), comprised of submarine chaser Bak Du San (PC 701), 1 tank landing ship, 15 minesweepers and minelayers, and 7,000 men, sortied from port in search of enemy forces. It did not take long for Bak Du San, whose crew had only recently brought their ship (formerly USS Whitehead) to South Korea from the United States, to find its prey. Bak Du San discovered a North Korean 1,000-ton steamer with hundreds of troops embarked off the east coast in the vicinity of the South Korean port of Pusan. The ROKN combatant sank the Communist ship, perhaps preventing seizure of the one port that would become vital to the UN forces fighting ashore.
United Nations help was on the way. With the outbreak of war, Vice Admiral C. Turner Joy, Commander Naval Forces, Far East, dispatched his 1 light cruiser, 4 destroyers, 4 amphibious ships, 1 submarine, 10 minesweepers, and an attached frigate of the Royal Australian Navy to Korean waters. Almost simultaneously, Admiral Arthur W. Radford, Commander in Chief, U.S. Pacific Fleet, transferred his subordinate Seventh Fleet to Admiral Joy's operational control. That fighting fleet, under Vice Admiral Arthur D. Struble, steamed from its Subic Bay, Philippines, home port on June 27, 1950, made a show off force off the coast of the bellicose People's Republic of China, and headed for Korean waters. Struble's aircraft carrier Valley Forge, heavy cruiser Rochester, 8 destroyers, 3 submarines, and a number of logistic support ships would be most welcome in the combat theater. The British Commonwealth soon complemented these American naval forces with aircraft carrier Triumph, 2 light cruisers, 3 destroyers, and 3 frigates. In July, the United States strengthened the ROKN with the provision of three decommissioned U.S. submarine chasers, more LSTs, and logistic ships and craft.
In the early hours of July 2, as the allied fleets converged on Korea, U.S. cruiser Juneau, British cruiser Jamaica, and British frigateBlack Swan discovered 4 torpedo boats and 2 motor gunboats of the North Korean navy that had just finished escorting ten craft loaded with ammunition south along the coast in the Sea of Japan. The outgunned North Korean torpedo boats turned and gamely pressed home a torpedo attack, but before they could launch their weapons, the Anglo-American flotilla ended the threat; only one torpedo boat survived U.S.-British naval gunfire to flee the scene. After this one-sided battle and for the remainder of the war, North Korean naval leaders decided against contesting control of the sea with the UN navies. The surviving units of the North Korean navy eventually took refuge in Chinese and Soviet ports.
Freed early from the threat of attack by enemy combatants, the allies' major warships could concentrate on the ground campaign. At this critical time for UN ground troops-then fighting to hold a precarious lodgment in South Korea-the fleet's carrier-based aircraft, battleships, cruisers, and destroyers poured bombs and shells on North Korean troops, tanks, and logistic vehicles pushing down both coasts of South Korea.
The allied navies still had much to do to deny the enemy use of the sea, however. During July, August, and early September, UN combatants, especially ROKN ships, were needed to disrupt the enemy's seaborne attempts to resupply the fast-advancing North Korean ground forces. Early in July, ROKN minesweeper YMS 513 sank three Communist supply craft at Chulpo on the southwestern coast and on the other side of the peninsula Juneau located and destroyed the ammunition vessels that figured in the 2 July sea battle. On the 22nd of July, YMS 513 sank another three enemy supply vessels near Chulpo. Five days later, submarine chasers PC 702 and PC 703, newly-provided by the United States, steamed up the west coast and sank twelve enemy sampans loaded with ammunition west of Inchon. During the first week of August, YMS 302 and other ROKN units destroyed another thirteen Communist logistic craft on the west coast. Between August 13 and 20, the ROKN engaged enemy supply vessels five times. In one instance, YMS 503 sank 15 enemy vessels and captured 30.
Combat action was especially heavy on the south coast during the last week of August, when the North Korean command was desperate to reinforce and resupply their troops trying to penetrate the Pusan Perimeter. Motor minesweepers YMS 503, YMS 504,YMS 512, and YMS 514, and PC 702 sank numerous enemy craft, many of whose embarked troops drowned, and captured many others. At the end of the month, the South Korean navy frustrated an enemy attempt to seize the port of Pohang on the Pusan Perimeter with troop-laden small boats. Finally, as the UN navies converged on Inchon for the amphibious assault that would turn the tide in the fall of 1950, PC 703 sank an enemy mine laying craft and three other vessels in waters off the Yellow Sea port.
Having secured control of the sea off Korea, the UN command could proceed with exploitation of that strategic advantage. With little fear from North Korean counteraction at sea, UN naval forces under Admiral C. Turner Joy deployed U.S. marine and army troops and South Korean soldiers ashore at Inchon on 15 September, landed other ground forces at Wonsan in northeastern Korea during October, and safely withdrew those forces from Hungnam in December when China's entry into the war once again altered the strategic balance. While the fortunes of war on the ground changed a number of times before the armistice of July 27, 1953, the UN allies never lost control of the sea.
Reproduced with permission from: Tucker, Spencer C. ed. Encyclopedia of the Korean War: A Political, Social, and Military History. Santa Barbara, CA: ABC-CLIO, 2000.