Wolfpack (naval tactic)

During the Handelskrieg (German war on trade) Allied ships travelled independently prior to the introduction of the convoy system and were vulnerable to attacks by U-boats operating as 'lone wolves'.

By gathering up merchant ships into convoys the British Admiralty denied them targets and presented a more defensible front if found and attacked.

In May 1918 six U-boats under the command of KL Rucker, in U-103, were operating in the English Channel; U-103 made contact with a troop convoy but was rammed and sunk by the troopship Olympic before she could attack.

[6] With the outbreak of the Second World War the U-boat Arm found the success of the pre-war trials had created some complacency; when these tactics were first tried in October 1939 (Hartmann's wolfpack) they were a failure; Hartmann found he was unable to exercise any tactical control from his boat at sea and the convoy attack was unsuccessful, while three U-boats were lost in the operation.

The revised approach saw Dönitz micromanaging operations at sea from his headquarters in occupied France, relying on the supposedly unbreakable Enigma code to transmit and receive orders and co-ordinate movements.

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.

As packs got larger the risks from this lack of co-ordination increased, such as overlapping attacks, collision or friendly fire incidents (in May 1943 for example, two U-boats stalking a Gibraltar convoy, U-439 and U-659 collided, with the loss of both).

Time and again escort groups were able to fight off numerically superior packs and destroy attackers, until the rate of exchange became ruinous.

Donitz’s pack tactic envisaged a patrol line of six to ten boats (later, twenty to thirty or more) across a convoy route to search for targets.

This situation improved with the fall of France and the occupation of the French Atlantic ports but U-boat construction had barely kept pace with losses and it was not until the summer of 1941 that several patrol groups were possible, creating the need to differentiate them.

At first this was by location (West, Centre, South, Greenland) but in August BdU began to assign codenames, chosen for their historical or cultural value.

[9] American wolfpacks, 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, Shad and Grayback – from Midway on 1 October 1943.

With trade returned to peacetime conditions and the end of convoying, the submarine ceased to be a commerce raider and moved to a range of more traditional military roles, such as scouting, intelligence-gathering, clandestine transport and in the event of a full-scale war, fleet operations.