The Merchant Tanker that was Built to Fight

[By William Thiesen, Ph.D., Coast Guard Atlantic Area Historian]

During World War II, the U.S. Navy operated a number of armed merchant ships, or “Q-ships,” in the Battle of the Atlantic. Q-ships were heavily armed merchant ships whose guns were hidden so that they could lure unsuspecting German submarines to the surface, then unmask the guns and attack the U-boats. As an answer to the Nazi strategy of concentrating U-boat attacks on oil tankers, none was more formidable than the Q-ship USS Big Horn.

The oil tanker SS Gulf Dawn undergoes conversion to the “Q-Ship” USS Big Horn (USN)

Big Horn was built in 1936 as the commercial tanker SS Gulf Dawn. Its conversion to a Q-ship began in March 1942 at the Bethlehem Shipyard, in Brooklyn, New York, and continued at the Boston Navy Yard where the work was completed in July 1942. The 425-foot tanker had a crew of 240 officers and enlisted men and could steam at 13 knots. The ship carried watertight barrels stored in cargo areas to provide added buoyancy if torpedoed and was equipped with underwater listening gear. Its armament included one 5-inch gun, four hidden 4-inch guns, and Hedgehog anti-submarine depth charges. Big Horn completed its final shakedown cruise in late August 1942.

Two of Big Horn's 4-inch guns are visible at bottom left and bottom right, concealed from surface view by false bulkheads (Courtesy USCG Cmdr. Douglas L. Jordan, ret'd.)

On its first cruise under the Navy, Big Horn operated out of Trinidad on the aluminum ore route. Later, the ship traveled in convoy between Trinidad and Norfolk and on at least one occasion was prevented from attacking Nazi submarines because convoy ships crossed through its line of fire.

After January 1943, when German submarines left U.S. waters, Big Horn began operations with a small task group of submarine chasers. In May, the crew of Big Horn sighted a periscope off their starboard bow and attacked the undersea contact, dropping depth charges for a four-hour period. During the attack, there was a heavy swirl as a U-boat dove below the surface and, later, an oil patch was visible over a wide area, indicating that a submarine had been hit.

In mid-summer 1943, Big Horn served as the flagship of another small task group, which patrolled the Atlantic north of the Azores and as far south as Brazil and West Africa. This was the last Q-ship patrol in which Big Horn participated.

One of Big Horn’s 4-inch deck guns is un-masked for gunnery drills. (Courtesy of USCG Cmdr. Douglas L. Jordan, ret'd.)

The Navy command cancelled the Q-ship program after it showed meager results. On Jan. 1, 1944, after completing its final cruise under Navy control, Big Horn was re-assigned to the Coast Guard for weather patrol duty. A Coast Guard crew boarded the ship on Jan. 7, 1944, and performed North Atlantic weather patrols for the next year. With armament intact, the crew of Big Horn could attack any U-boat that threatened them while carrying out their mission. Homeported in Boston, the crews continued to perform weather patrols in the North Atlantic until January 1945 and then returned to Navy control.

Crews fire Big Horn’s bow-mounted Hedgehog anti-submarine weapons during drills. (Courtesy USCG Cmdr. Douglas L. Jordan, ret'd.)

With the need for oil to fuel the final bloody campaigns in the Pacific, the Navy re-assigned Big Horn to tanker duty. Even though the cutter had officially returned to Navy service, the Coast Guard crew remained aboard. In March 1945, the crews took on a load of oil at Aruba and steamed through the Panama Canal for Pearl Harbor and on to the Marshall Islands. For the rest of the war, they supplied oil to the major battlefronts in the Philippines and Okinawa. After the war ended in August, Big Horn was temporarily stationed in Japan before returning to the U.S. in the spring of 1946. Big Horn decommissioned later that year.

USS Big Horn was one of several Q-ships operated by the U.S. Navy in the early part of the war. Among the others was USS Atik, sunk in March 1942 by a U-boat while on a shakedown cruise. Another was USS Asterion, which served as a Q-ship between March 1942 and October 1943. Like Big Horn, Asterion was re-assigned to the Coast Guard for weather patrol duty later in the war.

USS Big Horn marked a unique chapter in Coast Guard history. The ship was one of the only Coast Guard-manned Q-ships and, over the length of its service career, the crews performed combat missions, weather patrols and tanker duty. Big Horn and its crews are a part of the legend and lore of the U.S. Coast Guard.

This article appears courtesy of Coast Guard Compass and may be found in its original form here.