The Battle of the Atlantic

Hunter-Killer Groups

From the beginning of the war, German submarines - unterseeboots or u-boats - enjoyed considerable freedom of action in the Atlantic. The u-boats could strike almost at will, and did. Losses of merchant vessels carrying supplies and war materiel to England steadily mounted. The German crews called this "the Happy Time".

The Allies were operating under a number of handicaps:

• Very few ships were available to provide escort for the merchant convoys, and those that were available were ill-equipped for the task, being mostly old World War I types or coastal patrol vessels pressed into convoy service.
• Submarine detection equipment was rudimentary, consisting primarily of hydrophones - microphones lowered into the water to listen for the sounds of u-boats near the convoys. This was of limited use, as many factors - weather, fish, the convoy itself - could mask the sounds of the u-boats.
• Air cover was practically non-existant. Shore-based planes were limited in range, and there were no carriers available for convoy escort duties. A stop-gap measure, the catapult-assisted merchantman (CAM ship), proved of limited value. A catapult would be fitted to the deck of a merchant vessel and equipped with one fighter plane. Upon the detection of a u-boat or the sighting of a German long-range patrol bomber the plane would be launched to attack the target, or at least drive it off and spoil it's attack. As there was no capability to recover the fighter afterward, the pilot would bail out or ditch and (hopefully) be picked up by one of the ships of the convoy. Another near-desperation measure was the Merchant Aircraft Carrier, or MAC ship. A rudimentary flight deck would be built on the deck of a tanker or other bulk carrier, and up to four aircraft would be carried. No catapult, no hangar deck, no maintenance facilities (aside from the ship's regular machine shop) were provided.

As the war progressed, however, these obstacles were eventually overcome. New escort vessels began coming from the shipbuilders, equipped with the latest in detection equipment and weapons. Longer-ranged patrol bombers, operating from new bases around the Atlantic, provided extended air cover to the convoys and restricted the area that the u-boats could operate undetected. New tactics were developed, making the escorts and air patrols more efficient in defending against the attacks of the steel sharks.

But the greatest advantage gained by the Allies was the introduction of the escort carrier. These small ships, based on merchant ship hulls and carrying twenty to twenty-four aircraft, further extended the range of air cover to the entire Atlantic. Initially, escort carriers joined merchant convoys, providing increased defensive capabilities for the cargo ships.

However, the increased availability of the new escort carriers and warships allowed the creation of the most effective means of combatting the u-boat menace: the hunter-killer task group. An escort carrier would be teamed with up to a half-dozen destroyers and destroyer escorts. This formation would then seek out the u-boats in the formerly safe mid-Atlantic area, denying them the ability to operate unopposed.

Typical Escort Carrier Hunter-Killer Group

Task Unit 21.13, 14 November 1943
Bogue-class escort carrier:	CVE-9 USS Bogue
Clemson-class destroyers:	DD-186 USS Clemson, DD-196 USS George E. Badger, DD-255 USS Osmond Ingram
Wickes-class destroyer:	DD-152 USS DuPont

The first of these groups was formed around the new escort carrier CVE-9 USS Bogue in February 1943. Others soon followed. The "Happy Time" had come to an end.

One escort carrier, CVE-60 USS Guadalcanal, is credited with the only combat capture of a German submarine by the U.S. Navy during WWII - indeed, the only at-sea capture of an enemy combatant vessel since the War of 1812. On 4 June 1944, USS Guadalcanal, with the assistance of destroyer escorts DE-149 USS Chatelain and DE-133 USS Pillsbury, captured the German submarine U-505 off the coast of Africa.

Three other escort carriers -- CVE-13 USS Core, CVE-11 USS Card and CVE-9 USS Bogue -- along with their destroyer escorts are credited with the sinking of 16 combat U-boats and 8 milch cows (supply and refuelling submarines) over a three-month period.

In total, the escort carriers, their air groups and destroyer escorts accounted for fifty confirmed kills of German u-boats. Uncounted others were damaged and forced to return to base, or were prevented from accomplishing their missions. Additionally, attacks by land-based aircaft on the u-boat bases and on u-boats in coastal waters became more effective. In all, over 740 u-boats were sunk in all theatres.

These losses eventually led to the near-total cessation of German submarine activity in the Atlantic.

It should be noted that, despite the depredations of the u-boats, over 95% of merchant ships sailing the Atlantic during this period arrived at their destinations. The primary threat was not the immediate loss of ships and cargoes, but the political and psychological damage done by the sinkings. Politically, Allied leaders needed to be seen as expending maximum effort to defeat the enemy; u-boat sinkings of merchant vessels belied this impression. Psychologically, merchant seamen needed to be reassured that they would survive their service, or they would refuse to go to sea; ineffective defense of convoys did not help.

U-Boat Losses Credited to U. S. Escort Carrier Hunter-Killer Groups

Summary of U-Boat Sinkings by U. S. Escort Carrier Groups

Sources

Original table extracted from The Death of the U-Boats by Edwin P. Hoyt Hunter-Killer by William T. Y'Blood Escort Carriers in action (Warship book 9) by Al Adcock Hitler's U-Boat War: The Hunters, 1939-1942 by Clay Blair Hitler's U-Boat War: The Hunted, 1942-1945 by Clay Blair Clear the Decks by Daniel Gallery, Rear Admiral, USN (Ret.) U-505 by Daniel Gallery, Rear Admiral, USN (Ret.) The Battle of the Atlantic by Terry Hughes and John Costello World War II: America at War 1941-1945 by Norman Polmar and Thomas B. Allen

To Die Gallantly: The Battle of the Atlantic edited by Timothy J. Runyan & Jan M. Copes The Battle of the Atlantic by Andrew Williams The Little Giants by William T. Y'Blood Destroyers Online - Histories of decommissioned destroyers, destroyer escorts and frigates Escort Carrier Sailors & Airmen Association - Organisation of ship and air crews of United States Navy escort carriers Uboat.net: The U-boat War - 1939-1945 - German U-boat operations during the Battle of the Atlantic World War II Warships Archives - A brief history of the Atlantic War

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