The Shetland Bus (Norwegian Bokmål: Shetlandsbussene, def. pl.) was the nickname of a clandestine special operations group that made a permanent link between Mainland Shetland in Scotland and German-occupied Norway from 1941 until the surrender of Nazi Germany on 8 May 1945. From mid-1942, the group's official name was the Norwegian Naval Independent Unit (NNIU). In October 1943, it became an official part of the Royal Norwegian Navy and was renamed the Royal Norwegian Naval Special Unit (RNNSU). The unit was operated initially by a large number of small fishing boats and later augmented by three fast and well-armed submarine chasers – , and . Crossings were mostly made during the winter under the cover of darkness. This meant the crews and passengers had to endure very heavy North Sea conditions, with no lights and constant risk of discovery by German aircraft or patrol boats. There was also the possibility of being captured whilst carrying out the mission on the Norwegian coast. Early on it was decided that camouflage was the best defence, and the boats were disguised as working fishing boats and the crew as fishermen. The fishing boats were armed with light machine guns concealed inside oil drums placed on deck. The operation was under constant threat from German forces, and several missions went awry, of which the Telavåg tragedy in spring 1942 was a prime example. Several fishing boats were lost during the early operations, but after receiving the three submarine chasers there were no more losses. History Norwegian arrival When Germany launched Operation Weserübung, the invasion of Norway on 9 April 1940, French and British troops and ships were sent to help the Norwegians. Several coastal towns were bombed and destroyed by the Germans, and during April and May, the British ships had to retreat from mid-Norway. On 29 April, left the devastated city of Molde with King Haakon VII, Crown Prince Olav, members of the Norwegian Government, and most of the gold from the Norwegian National Bank. In northern Norway, the fighting lasted for another month. A few weeks after the occupation began, the first boats of an "armada" of fishing vessels and other boats began to arrive in Shetland. Some boats made several journeys across the North Sea carrying refugees. Many of the boats were "Hardanger Cutters", with a straight bow and long stern from the Bergen area, others the more rounded "Møre Cutters",