In May 1942 work commenced on the construction of a U-boat bunker in Nordrevågen, Laksevåg just west of Bergen. Only seven out of the planned ten pens were finally constructed, of which one was used for fuel storage, 3 were wet pens and 3 were dry pens. The wet pens on the north side of the bunker were each 11 meters wide and the dry pens were 17 meters wide. The roof was up to 6 meters thick and the walls were up to 4 meters thick. The entrances to the pens were protected by 3cm thick steel doors formed by hanging, overlapping plates. The overall size of the bunker was 130 metres by 143 meters.
The bunker was the home of 11 Unterseebootflotille for most of the war. The bunker took on an even greater strategic importance towards the latter stages of the war after the French bases were, one by one, closed down and abandoned.
The first bombing raid to destroy the bunker was scheduled for 24 July 1943 when 41 B-17’s from USAAF 4 th Bomber Wing headed for Bergen, but had to return to base because of bad weather over Bergen. The first major bombing raid, comprising over 130 RAF bombers, took place on 4 October 1944. The attack ended in a disaster when 193 Norwegians, among them 61 children at a nearby school, were killed. The bunker took several hits, but remained intact. Only two U-Boats were damaged.
The next major attack was carried out on 29 October 1944 and saw almost 250 RAF aircraft involved, though less than 50 eventually found and bombed the target. During this raid a Lancaster bomber, ND332, was hit by AA shells and crashed in Store Lungegårdsvann after dropping its bombs over Nøstet causing a lot of destruction.
The third and final raid on 12 January 1945 was launched by 32 RAF bomber carrying Tallboy bombs attacked the base. The bunker took 3 direct hits. One of the bombs penetrated through the roof, damaged two U-Boats and killed 20 Germans.
One source suggests that representatives from the British military suggested using the bunker for target practice after the war. Politically this was probably a non-starter, so shortly after the end of the war troops of the Royal Engineers demolished a large part of the Bergen U-boat bunker complex. In 1949, however, the Royal Norwegian Navy repaired and refitted the dry-dock facilities and at the same time infilled pens 4, 5 and 6, forming a quay alongside the dry-dock facilities.
In 2004 the bunker was declared a listed building, but to this day is still used by the Norwegian Navy.