Wolf Pack

Extract from ‘Tactics and Operations: The U-Boat Campaign’

Tactics

Before considering the actual U-boat campaigns, a brief examination of the tactics employed may be useful to understanding the operations.At the onset of war, Hitler had insisted that U-boats, and indeed surface ships also, should operate within the terms of the Prize Ordinance. The German rules, or to give them their correct title, ‘Article 74 of the German Prize Ordinance’, was based on an agreement which became effective in 1936, the Procès Verbal to the Rules of Submarine Warfare set forth in Part IV of the Treaty of London of 22 April 1930. This stated: Except in the case of persistent refusal to stop on being duly summoned, or of active resistance to visit or search, a warship, whether surface vessel or submarine, may not sink or render incapable of navigation a merchant vessel without having first placed passengers, crew and ship’s papers in a place of safety. For this purpose the ship’s boats are not regarded as a place of safety unless the safety of the passengers and crew is assured, in the existing sea and weather conditions, by the proximity of land, or the presence of another vessel which is in a position to take them on board.

This highly restrictive set of rules required that any suspect ship be stopped and searched, and then sunk only if it were found to be carrying contraband. Even then, the crew had to be evacuated and its safety assured before the sinking. Whilst the first part of this rule created problems which, while difficult, were not insurmountable, it was almost impossible for a U-boat to assure the safety of the crew of a ship it had sunk. Placing the crew into lifeboats was not sufficient to comply with these rules, as there was no guarantee that the survivors in the lifeboats would subsequently be picked up. Clearly the restricted space within a U-boat precluded taking the enemy crew on board, and this left the U-boat captain in an almost impossible situation. Unless the lifeboats were within easy rowing distance of land, or on a busy shipping lane where their rescue in a short period of time was almost certain, the U-boat captain would almost certainly find himself in breach of Prize Ordinance rules. Moreover, some merchantmen would attempt to ram the U-boat if the chance arose, and would certainly send off a warning signal by radio which could bring swift attention from enemy ships or aircraft, so that a leisurely stop and search routine was hardly a viable option. Although the liner Athenia was sunk in the opening days of the war by Kapitänleutnant Fritz-Julius Lemp of U-30, who had mistaken her for a troopship, German adherence to these rules continued for some time. Hitler was keen not to sink ships which might be carrying neutrals such as Americans, and thereby risk the USA being drawn into the war in a repeat of the Lusitania incident in World War I. Nevertheless, restrictions on attacking enemy ships were gradually eased, though adherence to the Prize Ordinance continued to a considerable degree until as late as August 1940. Ships travelling in convoy however, were soon considered fair game for the U-boat commander.

Restrictions were first eased on 23 September when U-boats were given permission to attack any ship using its wireless to summon aid. On the following day, restrictions against attacks on French vessels were lifted. On the last day of the month, the application of Prize Rules was lifted against vessels encountered in the North Sea. A further extension of the area in which the use of Prize Rules was to be lifted was declared on 2 October and on 17 October U-boats were permitted to attack all ships positively identified as ‘hostile’. Attacks on liners, previously prohibited, were permitted from 17 November if the vessel was identified as ‘hostile’.

In the early part of the war, U-boats tended for the most part to act alone, patrolling designated areas in search of the enemy. This was as much due to the sheer lack of available numbers as to any other factor. In the early months of the war it is estimated that there were rarely ever more than around half a dozen U-boats at sea at any one time. Notwithstanding the small numbers of boats available, a number of notable successes were scored within weeks of the outbreak of war. In mid-September, British attempts to beef up the strength of convoy escorts by adding small aircraft carriers were thwarted when the carrier Courageous was sunk by U-9, and barely one month later Kapitänleutnant Günther Prien in U-47 penetrated the fleet anchorage at Scapa Flow and sank the battleship Royal Oak.

Although the convoy system had already been introduced at the start of the war, lack of suitable numbers of escort vessels meant that the bulk of shipping was still sailing independently, many vessels depending on their relatively fast speed to keep them out of danger. The older, slower vessels, too, were left out of convoys lest they slow them down too much, the convoy only being able to proceed at the speed of the slowest ship if it was to stay together.

What has become universally known as the ‘Wolf pack’ originated in World War I, though during that conflict it was never fully developed. There is considerable argument over who was responsible for the introduction of the tactic, Dönitz himself claiming credit whilst others scorn his claim and suggest that Kommodore Bauer may have been the originator. Given that military units operate in groups (battalions, regiments, etc.), aircraft fly in groups (squadrons, wings, etc.) and even surface ships rarely operate solo but in concert with other craft from their flotilla, the concept of operating U-boats in groups must have been one which many U-boat commanders saw as having definite advantages. Dönitz, however, in his capacity as BdU was certainly the one who was in a position to implement and develop the tactic.

Initially, the early version of what has generally become known as wolf pack tactics consisted of attacks on Allied convoys by groups of U-boats. When one boat spotted a convoy, other boats within striking distance would be instructed to join in the attack. These boats before and after the attacks operated independently and so the ‘pack’ only existed for the duration of the attack. True wolf packs, where the boats operated as a group from the outset, only came into general use in 1941.

During the first part of the war, the ‘group’ tactic worked relatively well and some considerable successes were achieved. Many of the better commanders, however, developed their own tactics. The perceived wisdom at the time was that a U-boat would stand off from the convoy by a couple of kilometres or more, submerged, and fire a ‘spread’ of torpedoes at the convoy, anticipating at least some hits. Aces like Otto Kretschmer, however, found that at night, with the U-boat being such a small vessel, he could approach a convoy on the surface and even penetrate into the convoy without detection. From such a close range, he would be almost guaranteed a hit with each torpedo. Barring faulty torpedoes, Kretschmer’s goal of ‘one torpedo – one ship’ was attainable.