The term wolfpack refers to the mass-attack tactics against convoys used by German U-boats of the Kriegsmarine during the Battle of the Atlantic, and by submarines of the United States Navy against Japanese shipping in the Pacific Ocean in World War II.
Karl Dönitz used the term Rudeltaktik to describe his strategy of submarine warfare—Rudeltaktik translates best as "tactics" of a "pack" of animals and has become known in English as "wolfpack" (Wolfsrudel), a more accurate metaphoric, but not literal, translation.
U-boat movements were controlled by the Befehlshaber der Unterseeboote (BdU; English translation: "Commander of Submarines") much more closely than American submarines, which were given tremendous independence once on patrol. Accordingly, U-boats usually patrolled separately, often strung out in co-ordinated lines across likely convoy routes (usually merchants and small vulnerable destroyers), only being ordered to congregate after one located a convoy and alerted the BdU, so a Rudel consisted of as many U-boats as could reach the scene of the attack. With the exception of the orders given by the BdU, U-Boat commanders could attack as they saw fit. Often the U-Boat commanders were given a probable number of U-Boats that would show up, and then when they were in contact with the convoy, make call signs to see how many had arrived. If their number were sufficiently high compared to the expected threat of the escorts, they would attack.
Although the wolfpacks proved a serious threat to Allied shipping, the Allies developed countermeasures to turn the U-boat organization against itself. Most notably was the fact that wolfpacks required extensive radio communication to coordinate the attacks. This left the U-boats vulnerable to a device called the High Frequency Direction Finder (HF/DF or "Huff-Duff"), which allowed Allied naval forces to determine the location of the enemy boats transmitting and attack them. Also, effective air cover, both long-range planes with radar, and escort carriers and blimps, allowed U-boats to be spotted as they shadowed a convoy (waiting for the cover of night to attack).
American wolfpacks, officially called coordinated attack groups, usually comprised three boats that patrolled in close company and organized before they left port under the command of the senior captain of the three. "Swede" Momsen devised the tactics and led the first American wolfpack – composed of Cero (SS-225), Shad (SS-235), and Grayback (SS-208) – from Midway on 1 October 1943.
Wolfpacks fell out of use during the Cold War; modern submarines have far better weapons and underwater speed than those of World War II, so there is no need for them to operate in large groups. Instead, the United States Navy deploys its attack submarines on individual patrols, with the exception of one or (rarely) two attack submarines in each carrier strike group.
American ballistic missile submarines have always operated alone, while Soviet ballistic missile submarines operated in well-protected bastions.
With the opening shots of the Iraq War in March, 2003, the term "wolfpack" was brought back into use to describe the fleet of American and British nuclear submarines which operated together in the Red Sea, firing Tomahawk missiles at Iraqi targets. USS Providence was the first boat to fire its entire load of missiles and earn the nickname "Big Dog of the Red Sea Wolf Pack."
Recently the phrase "wolfpack" has been applied to possible Iranian missile boat tactics in the event of a hypothetical clash with the U.S. Navy; a massive attack of small boats armed with missiles and torpedoes on a single (or a few) ships in order to overrun or saturate the Aegis defense system. Such attacks allow the possibility of effective sacrificial boat deployment.