Jun 1940 Mar 1941 Apr 1941 Dec 1941 Jan 1942 Jul 1942 Aug 1942 May 1943 Jun 1943 Aug 1943 Sep 1943 May 1945 convoy system was still being built up and the ocean still carried a large proportion of independently routed merchant ships the number of easy targets had presented many opportunities to skilled commanders to amass a considerable tonnage to their personal credit. The U-boat commanders themselves referred to the first year and a half of the war as 'the happy time. By February 1941 the three greatest of the U-boat 'aces were Gunther Prien who had sunk the Royal Oak in Scapa Flow and claimed over 150,000 tons of merchant shipping and Joachim Schepke and Otto Kretschmer both of whom claimed over 200000 tons of Allied shipping sunk. All three of them had been decorated by Hitler with the Knights Cross with Oak- leaves for their outstanding success and all three were men from whom other U-boat commanders drew their inspiration. But by March all three had been eliminated from the battle. Prien in U-47 was sunk on March 7 by the corvettes Arbutus and Camellia and the destroyer Wolverine Schepke in U-100 was sunk on March 17 by the Walker and Vanoc and on the same night these same destroyers sank U-99, taking Kretschmer prisoner ashe escaped from his sinking U-boat. It was a heavy blow for Germany for these three had been widely recognised in Germany as the cream of the U-boat commanders. March 1941 saw the virtual end of the independent U-boat attack. As more and more merchant ships were brought into the convoy organisation and as the range of convoy was extended farther across the Atlantic, the day of the individual U-boat was over. The British adoption and extension of convoy forced the U-boat command to workout new tactics and it was from this situation that the pack attack at night was developed. There was nothing basically new in this. A rudimentary form of pack attack had been evolved during the last year of the First World War but had not been very successful because wireless signals necessary for control of the pack were still relatively speaking in their infancy. Tentative pack- tactics had appeared in the Atlantic in 1940, but had not been developed because the individual U-boat operating in a fixed area was still finding sufficient targets to make its presence there well worthwhile. Those days, however were now over for good although in early 1942 the U-boats experienced another brief 'happy time. This followed the entry of the United States into the war, when a small number of U-boats concentrated on the eastern American seaboard and took a heavy toll of the unescorted shipping there. Six months later when this shipping too was organised into convoys these U-boats withdrew abruptly. In the organisation of the pack attack the U-boat command relied on one U-boat of the pack shadowing a convoy during daylight and homing in the remainder by directional wireless as night approached. All attacks were then made on the surface during the hours of darkness when the tiny superstructure of the U-boat was well-nigh invisible to the defenders. With her high surface speed and her virtual invisibility, the advantages of night attack to the U- boat were considerable. Yet the whole system had in it one element of weakness. The shadowing U-boat was forced to make a series of wireless signals reporting the convoys position, speed and alterations of course. These signals were invariably picked up by Allied directional-finding stations and the bearings when plotted in the British Admiralty’s U-boat tracking room revealed the position of the shadower. For the Germans the Battle of the Atlantic had two purposes and two phases. At first the Germans were trying to strangle Britain's lifelines across the Atlantic but by 1942 the U-boats were fighting to prevent the establishment of an Allied invasion-force in Britain. Both phases were governed by the ‘Black Gap in mid-Atlantic where Allied escorts could not protect the vital convoys. The occupation of Iceland in 1940 had been the first step towards closing the gap but no positive counterattack could hurt the U-boats until long-range frigates and escort-carriers could shepherd the convoys all the way across. In the spring of 1943 with the Torch landings safely over the attack on the U-boats began in earnest. The diagram below shows how the gap was closed and depicts the major Atlantic convoy routes and U-boat bases S ep 1939 May 1940
We have sought to ensure that the content of this website complies with UK copyright law.
Please note however, that we may have been unable to ascertain the rights holders of some items.
Where we have digitised items, we have done so with items that to the best of our knowledge,
following due investigations, are in the public domain. While the original works are in the public domain
we reserve all rights to the usage of the digital works.