of alluvial gravel was acceptable for an airstrip and the south-eastern orientation of the high ground did not impede wireless communication with Banak in Norway; the settlement of Longyearbyen was close by. The site received the code-name (from Banak and Spitzbergen Öya) and ferry flights of men, equipment and supplies began on 25 September. The British followed events from Bletchley Park through Ultra and four British minesweepers were diverted to investigate and reached Isfjorden on 19 October. A 5 aircraft crew spotted the ships and the thirty men at Adventfjorden quickly were flown to safety by the aircraft and two Junkers Ju 52 transport aircraft. Adventfjorden was deserted when the British arrived but some code books were recovered; the Germans returned once the ships had departed. Dr Albrecht Moll and three men arrived to spend the winter of 1941–1942 transmitting weather reports. On 29 October 1941, Hans Knoespel and five weathermen were installed by the at Signehamna, a small bay on Lilliehöökfjorden, a branch of Krossfjorden in the north-western Spitzbergen. An automatic weather station () with a thermometer, barometer, transmitter and batteries arrived at Banak, to be flown to and the Moll party brought back. It took until 12 May for favourable weather and a Heinkel He 111 and a Junkers Ju 88 were sent with supplies and the technicians to install the . In April 1942, Operation Fritham the landing of a Norwegian force at Barentsburg to occupy the islands. The operation met with disaster but by the summer of 1943, the later Allied Operation Gearbox and Operation Gearbox II secured control of the islands. Prelude The decided to evacuate the weather station during the summer of 1942, since the ice-free season made it vulnerable to Allied attack. The submarine (K Siegfried Strelow) was ordered to recover the six men. On 23 August 1942, Strelow took aboard the party at Ebeltofthamna in Krossfjorden on the Mitra peninsula, without Allied interference and arrived at Narvik on 31 August. After the replacement of (Grand Admiral) Erich Raeder by Karl Dönitz in January 1943, command arrangements in northern waters were changed. The posts of Flag Officer Northern Waters at Narvik was merged with Group North, which brought the commander of the German ships at Alte Fjord under the command of Otto Schniewind at Kiel. Dönitz persuaded Hitler not to scrap the surface fleet and made plans to demonstrate the value of the