Wolfpack (naval tactic)

• 1. Introduction

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  The wolfpack, in October 1918, was costing the man who would later perfect it his freedom. Two German submarines attempted a co-ordinated attack on a convoy in the Mediterranean. One boat was sunk. Its commander, an officer named ObLt Karl Dönitz, was taken prisoner. The tactic he had just failed to execute would occupy the rest of his career.

  Rudeltaktik was the name Dönitz would eventually give to his refined version of the idea. It translates as "pack tactic," and he chose the name deliberately. German submariners already called their boats graue Wölfe, grey wolves. One submarine would find a convoy, radio its position to headquarters, and hold contact while others converged for a combined strike.

  Germany entered the Second World War with just 27 ocean-going U-boats. That number was barely enough to mount a single patrol line across the Atlantic. It would shape every calculation about where and how the wolfpack could fight.

• 2. The Channel's First Lesson

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  In early 1917, Hermann Bauer proposed the original version of the idea. As Führer der Unterseeboote, commander of the High Seas U-boats, Bauer envisioned patrol lines of submarines stretched across convoy routes. A headquarters vessel stocked with radio equipment, fuel, and torpedoes would support them. A shore station would monitor enemy transmissions. When a convoy appeared, the boats would mass and strike together.

  In May 1918, six U-boats under KL Rucker tested that plan in the English Channel. U-103 made contact with a troop convoy but was rammed by the troopship before it could fire. UB 72 was caught on the surface by a British submarine and torpedoed and sunk. When the operation ended, 19 homeward-bound and 11 outward-bound convoys had passed through the patrol area without a single loss. Two of the six boats, a full third of the force, had been destroyed.

  Germany would be forbidden from operating U-boats in the years that followed. The wolfpack idea went into suspension, waiting for a different kind of war.

• 3. A Tactic Rebuilt

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  Germany's navy began re-arming in 1935, ending the post-war prohibition on U-boats. Karl Dönitz, serving as FdU, drew on Bauer's 1917 plan and developed co-ordinated attack tactics from his own experience. His 1936 exercises of the new approach proved successful, but complacency from that pre-war success would prove costly.

  October 1939 brought the first operational test, a mission that became known as Hartmann's wolfpack. It failed. Hartmann found he was unable to exercise any tactical control from his boat at sea. Three U-boats were lost in the operation. A further attempt the following month also failed.

  Rösing's wolfpack, mounted in June 1940 following the Norwegian campaign, failed as well. Three consecutive failures in under a year forced a complete rethink of German tactics. The answer came from moving command entirely off the ocean, to headquarters on the shores of occupied France.

• 4. Command from Kerneval

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  U-boat Command, known as BdU, ran all wolfpack operations from Kerneval in occupied France. Dönitz micromanaged the campaign from there, transmitting and receiving orders through what the Germans believed was the unbreakable Enigma code.

  Dönitz envisaged patrol lines of six to ten boats, and later twenty to thirty or more, strung across likely convoy routes. Boats patrolled alone until one of them made contact with a convoy. BdU would then direct the others to break their individual patrols and close on the target.

  BdU gave commanders on scene a probable count of U-boats expected to arrive. Once in contact with the convoy, they made call signs to confirm how many had assembled. If that number looked sufficient against the expected escort strength, they attacked. Individual commanders were otherwise free to move against the convoy as they saw fit.

  Successful pack attacks in the latter half of 1940 led U-boat crews to call this period "the Happy Time."

  Until the summer of 1941, packs were named after the skipper who had found the target convoy, and patrol lines had no names at all. Growing U-boat numbers then made several simultaneous patrol groups possible, creating a need to distinguish them. BdU first used location designations like West, Centre, South, and Greenland. Then in August 1941, the command began assigning codenames drawn from history and culture.

  The Goeben group was assigned to enter the Mediterranean and support operations there rather than hunt convoys. Eisbär group was dispatched to the waters off South Africa, where its boats operated independently. The last named U-boat group would be Seewolf, seven boats sent against the North American coast and countered by the US Navy with Operation Teardrop.

• 5. The Radio Trap

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  The High Frequency Direction Finder, known to Allied sailors as Huff-Duff, allowed Allied forces to determine the location of any U-boat transmitting. Every radio message sent to co-ordinate an attack could reveal the position of the boat that sent it. Allied naval forces could then move to attack that boat before it struck.

  In May 1943, two U-boats stalking a Gibraltar convoy collided and both were lost. As packs grew larger, the risks from overlapping attacks, collisions, and friendly fire incidents multiplied. Escort groups responded by developing organized group tactics against U-boat attack, gaining a systematic advantage that unco-ordinated wolfpack commanders could not match.

  Escort carriers and blimps extended Allied reach still further. Long-range aircraft equipped with radar could spot U-boats while they shadowed a convoy, waiting for the cover of night to attack. The expansion of the escort force, combined with well-organized escort groups, pushed the rate of exchange until it became ruinous for Germany.

  Operation Drumbeat, off the US eastern coast in early 1942, had used individual U-boat patrols rather than packs. So had Operation Neuland in the Caribbean. The South Atlantic and the Indian Ocean saw the same lone-wolf approach. After the spring of 1944, the German submarine arm abandoned pack attacks entirely, shifting to individual patrols in British coastal waters.

  In the Pacific, the United States Navy was building a co-ordinated submarine force of its own. It had a different answer to every flaw the German wolfpack had exposed.

• 6. The American Answer

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  On the 1st of October 1943, the first American wolfpack departed from Midway. The officer who devised the tactics, known as "Swede" Momsen, led that mission personally. His approach addressed the central problem the German version never fully solved: how to make command at sea actually work.

  American coordinated attack groups usually comprised three submarines, operating in close company. They formed before leaving port and sailed under the command of the senior captain of the three. Stable, small groups could develop genuine group tactics against Japanese convoys. The German wolfpack had relied on whichever boats arrived acting independently.

  Rear-Admiral Ralph Christie, commanding the South West Pacific force from Brisbane and Fremantle, preferred individual patrols. Rear Admiral Charles Lockwood at Pearl Harbor, running SubPac, was the wolfpack's strongest advocate in the Pacific. The two commands maintained different approaches for much of the war.

  Cdr. "Ben" Oakley's group became known as "Ben's Busters." Another group was called "Blakely's Behemoths." Naming the groups was part of building esprit de corps. The American submarine force devastated the Japanese merchant marine during the war years, though the wolfpack tactic was one factor among several.

  Soviet ballistic missile submarines, during the Cold War, operated in well-protected bastions rather than open packs. The US Navy deployed its attack submarines on individual patrols, with one or rarely two assigned to each carrier strike group. The world's navies have continued that practice to this day.