The Battle of the Atlantic had been raging for over two years before the U.S. joined the war and Coast Guard operations in the North Atlantic began well before the U.S. entered the war. Cutters performed convoy escort duty side-by-side with British and Canadian ships. Once the U.S. entered the war, the cutters became fully involved in the battle. In the grand scheme of convoy routing, the U.S. was responsible for the western half of the Atlantic. U.S. escort groups escorted convoys from Halifax to the English coast and then pick up a west-bound convoy and escort it to Halifax. Adm. Doenitz’s u-boats waited in the middle.
U-boat tactics called for centralized radio control. The British developed a high-frequency radio direction finder, called “huff-duff” to locate them based on their constant radio use. The Coast Guard manned shore-based huff-duff stations. In 1942, shipboard huff-duff became available making intelligence available to the escorts on scene. The escorts used radar to locate surfaced u-boats and sonar to track submerged ones. The fact that England had broken the German naval code using Ultra technology was counterbalanced by the fact that the Germans had also broken the Allied merchant codes. So, even though the Allies knew the German locations and plans, the Germans also knew the convoy routes and makeups.
The Allies used long-range aircraft fling from land bases in the States and England to cover the convoy for most of its route. But an air gap existed south of Greenland where most of the coming battles were waged. The Germans called it the “Devil’s Gorge”, the Allies, “Torpedo Junction”.
The North Atlantic storms in the winter of 1942-1943 were the worst in 50 years, rendering radar and sonar almost useless. Over 100 u-boats waited in the path of the convoys. The resulting carnage has been called the “Bloody Winter”.
Through 1943, only one escort group, Ocean Escort Group A-3, was under American command. It was commanded by Capt. Paul Heineman, USN, and consisted of USCGC Spencer, USCGC Campbell, one British, and four Canadian corvettes. Ships often transferred between groups and groups, when under threat of attack, were often reinforced by ships held in reserve in Iceland. Ships held in reserve in Iceland included USCGCs Bibb, Duane, Ingham, and Hamilton (lost on 29 January 1942). These six cutters were of the newly commissioned Secretary-class. Spencer and Campbell had shipboard huff-duffs.
The first Coast Guard action came on 17 December 1942 when Ingham, escorting Convoy SC-112, sent U-626 to the bottom with all hands. Later, a wolf pack attacked SC-118, sinking SS Henry Mallory. Bibb and Ingham ignored a British command to maintain course and stopped to assist Mallory’s crew. Coastguardsmen jumped over the side to pull 235 survivors to safety. Bibb then rescued another 33 men from the stricken SS Kalliopi before rejoining the convoy.
In February 1943, Convoy ON-166, bound for Halifax, was attacked. On 20 February, Spencer attacked a radar contact and drove off U-604. On 21 February, Spencer gained a sonar contact, attacked, and sent U-529 to the bottom. Campbell attacked and damaged two u-boats and rescued 50 men from a Norwegian tanker. She then attacked a sonar contact, forced U-606 to the surface, and rammed her, incurring damage to her engine room in the process. She drifted for four days until a tug towed her to Newfoundland. Spencer then attacked and damaged U-454 in the final action of the week-long, 1,000-mile battle.
March was the deadliest month of the war in the North Atlantic. In the first three weeks, the Allies lost 97 ships, and even America’s industrial strength could not keep up. Convoy SC-121 lost 13 out of 59 ships.
On 16 April, Spencer forced U-175 to the surface. After a gun battle, the German crew abandoned their ship. A boarding party led by Lt. Ross Bullard determined that the u-boat could not be salvaged. Bullard became the first American serviceman to board an enemy warship underway at sea since the 19th century. Spencer then rescued the 41 German crewmen.
The Allies added destroyer escorts and patrol frigates to the convoys. A major innovation was the escort carrier, which carried ASW aircraft and eliminated the air gap. In May 1943, the Allies sank 41 u-boats. In July, 45 u-boats went to the bottom taking only 24 cargo ships with them. Doenitz retired his u-boats from the North Atlantic.
By 1944, the Coast Guard manned 30 Edsall-class Destroyer Escorts (DEs) and the entire 75-ship class of Tacoma-class Patrol Frigates (PFs). In March 1944 Leopold became the first Coast Guard DE sunk by a u-boat. In April, Joyce sank U-550.
In 1945, the Navy moved to hunter-killer group. CDR Reginald French commanded Coast Guard-manned Escort Division 46, comprised of Pride, Menges, Mosley, and Lowe. This group accounted for the last three Coast Guard u-boat kills, U-866, U-857, and U-853, in April and May of 1945.
For a complete list of cutters engaged in the Battle of the Atlantic (North Atlantic and Malta) go to this Link.
For a complete list of Navy combatants manned by the Coast Guard go to this Link.