and allocated numbers in the range U-5501 to U-6442. Operational service The first Seehund operation took place on 31 December 1944, when 18 craft set out from IJmuiden in the Netherlands. However, this was a disaster – the submarines encountered a storm and only two returned. The first sinking by a Seehund did not occur until February 1945, when a freighter was sunk off Great Yarmouth. Seehunds operated mainly around the German coast and in the English Channel, and could attack on the surface in turbulent weather, but had to be almost stationary for submerged attacks. From January to April 1945 Seehunds performed 142 sorties, and accounted for about 93,000 gross tons of shipping (British sources estimate 120,000 tons). Administratively, the Seehunds were under the command of Lehrkommandos, which were part of the German Navy's special operations branch. Within each Lehrkommando were subordinate K-Flotilla; K-Flottille 311 was specifically designated to oversee deployment of the Hecht miniature submarine while the Seehund submarines were dispersed between K-Flottille 312, 313, and 314. From the Allied point of view, the Seehunds small size made it almost impossible for Asdic to get a return from her hull, while her very quiet slow-speed running made her almost immune to detection by hydrophone. As Admiral Sir Charles Little, Commander-in-Chief, Portsmouth, put it, "Fortunately for us these damn things arrived too late in the war to do any damage". The last Seehund sorties took place on 28 April and 2 May 1945, when two special missions were performed to resupply the besieged German garrison at Dunkirk with rations. The boats carried special food containers (nicknamed "butter torpedoes") instead of torpedoes, and on the return voyage used the containers to carry mail from the Dunkirk garrison. The French navy received four units as war reparations, and commissioned them as S 621, S 622, S 623 and S624. They were used until August 1953. Survivors One of the boats used by the French navy post-war, U-5622, is preserved and on display at the Musée national de la Marine in Brest, France. U-5075 is on display at the United States Naval Shipbuilding Museum, part of the Massachusetts Military Research Center, in Quincy, Massachusetts. Occasional amateur radio events are conducted by this museum ship, using the callsign WW2MAN. In Germany, Seehunds are displayed at several museums, the Technik Museum Speyer, the Deutsches Museum, Munich, the Marinemuseum Wilhelmshaven and the German Maritime Museum