Admiral Karl Dönitz, commander of the German submarine force, recognized that unless the U-boats could overcome the defenses of Allied merchant convoys, the tonnage war would inevitably be lost. His solution was a concept that came to be called Rudeltaktik, or wolf pack attack—a method for U-boats to penetrate a convoy's antisubmarine defenses and destroy the merchant ships. Once a U-boat located an Allied convoy, other submarines would be vectored to that location. Groups of U-boats would then attack on the surface at night at relatively high speeds, maximizing the effect. U-boats would operate in a "hit-and-run" manner, launching their attack and then fleeing on the surface before the convoy's surface escorts could react.
Dönitz's intelligence staff also broke the British convoy codes and supplied specific information concerning departure and arrival schedules, escort strength, and weather reports from all ocean areas. Success in the intelligence war was critical in locating targets for U-boat concentrations.
By late 1942, Dönitz had over 200 operational U-boats with which to implement wolf pack operations. Some Italian submarines also participated. A wolf pack generally consisted of 6 to 9 U-boats, but some utilized as many as 20 to 30. Wolf packs were identified with code names, such as lowenherz ( lionheart) or streitaxt (battle axe), giving the submariners a sense of cohesion and collective focus for the operation. Each pack deployed into a concave patrol line with about 10 miles between each pack member. Using darkness, the U-boats would operate on the surface to lessen the effectiveness of Allied asdic, and the compact silhouette of the U-boat helped provide natural protection. The patrol line combed the Atlantic in an east or west direction, maintaining radio silence while under control by radio from Dönitz's command post at Lorient, France.
When an individual submarine sighted a convoy, it would immediately radio the convoy's position and course to Dönitz's headquarters, which would then relay orders for the pack to concentrate the line inward on the projected course of the convoy. The U-boat that originally established contact would shadow the convoy at a safe distance and keep headquarters advised of any change in the convoy's course.
When at least three U-boats came in contact with the convoy, the attack began, and Dönitz turned immediate control of the battle over to the individual U-boat commanders. The wolf pack, however, had little opportunity to cooperate tactically, as Allied radio detection prohibited communications between individual boats. However, the multiboat attack would confuse and disrupt the escorts, thereby improving each boat's chance of gaining an effective position from which to launch an attack. The U-boats would fire a "fan" or salvo of three or four torpedoes along several paths to increase the chances of a hit. Because the convoy formed a compact target, a single salvo might result in several hits on different ships within the formation. After their attacks, the U-boats submerged to escape counterattack.
Unless the convoy managed to elude the wolf pack by a radical change of course, the merchant ships might be hounded by the pack over several successive nights. The action would be broken off only when the U-boats had exhausted their torpedoes or the convoy reached a point where continuous air cover could be provided. These tactics resulted in the sinking of almost 400,000 tons of Allied shipping a month during late 1942, with a peak occurring in November when 118 ships were sunk for a total of 743,321 tons.
The Achilles heel of the wolf packs, however, was the radio communication between the U-boats and Dönitz's headquarters. The Allies introduced high-frequency direction finding (HF/DF) equipment in faster Allied escort vessels to drive away the shadowing U-boat, thereby forcing it to submerge or destroying it with depth charges or air attack. Allied technical superiority, the use of long-range aircraft, and code breaking culminated in May 1943 when the Allies destroyed over 40 German submarines. "Black May" signaled the defeat of the wolf packs as the ratio of Allied tonnage produced to tonnage sunk by the U-boats tipped against the Germans.
During World War II, over 130 wolf packs operated against Allied shipping, sinking more than 2,759 Allied merchant ships and 138 warships and killing almost 60,000 seamen. Of the 1,170 U-boats Dönitz employed throughout the war, 753 were lost, along with some 29,000 crewmen.
Steven J. Rauch
Edwards, Bernard. Dönitz and the Wolf Packs. London: Cassell, 1999.; Time-Life Books. Wolf Packs. Alexandria, VA: Time-Life Books, 1989.; Von der Porten, Edward P. The German Navy in World War Two. New York: Ballantine Books, 1974.