for Trondheim. British military intelligence, which was capable of decrypting the Enigma messages sent by the German navy, detected the departure of the vessel, but poor weather in Britain prevented action by the RAF. Admiral John Tovey, the commander in chief of the British Home Fleet, was not made aware of Tirpitzs activities until 17 January, well after the ship had arrived in Norway. On 16 January, British aerial reconnaissance located the ship in Trondheim. Tirpitz then moved to the Fættenfjord, just north-east of Trondheim. The movement was codenamed Operation Polarnacht (Polar Night); the battleship was escorted by the destroyers , , and for the voyage. The Norwegian resistance movement transmitted the location to London. She was moored next to a cliff, which protected the ship from air attacks from the southwest. The ship's crew cut down trees and placed them aboard Tirpitz to camouflage her. The crew also frequently hid the entire ship from aerial reconnaissance and attacks inside a cloud of artificial fog, created using water and chlorosulfuric acid. Additional anti-aircraft batteries were installed around the fjord, as were anti-torpedo nets and heavy booms in the entrance to the anchorage. Tirpitz was known as the "Lonely Queen of the North" because she was so rarely deployed, and life for her crew was very monotonous. Frequent fuel shortages curtailed training and kept the battleship and her escorts moored behind their protective netting. The crew was primarily occupied with maintaining the ship and continuously manning anti-aircraft defences. Sports activities were organised to keep the crew occupied and physically fit. Operations against Allied convoys Several factors hindered Tirpitzs freedom of operation in Norway. The most pressing were shortages of fuel and the withdrawal of the German destroyer forces to support Operation Cerberus, the movement of the battleships and and the heavy cruiser through the English Channel. These caused a planned attack against the outbound convoy PQ 8 at the end of January to be abandoned. A planned British air attack at the end of January by four-engined heavy bombers was disrupted by poor weather over the target, which prevented the aircraft from finding the ship. In early February, Tirpitz took part in the deceptions that distracted the British in the run-up to Operation Cerberus. These included steaming out of the fjord and the appearance of preparations for a sortie into the North Sea. Later that month, the ship was reinforced by