The Norwegian Marine forces
The Norwegian Navy was built up heavily at the end of the 19th and beginning of 20th century, first due to the tension around the break of the union with Sweden, then around WW1. After that, not very much had happened, and that was apparent in 1940.
From the outbreak of WW2 the Naval forces had been deployed for neutrality watch. That is escort duty and patrol. As a consequence the units were dispersed along the coast when the invasion came. After the initial German landings they had not only lost many of their best ships. They were also deprived of their main bases and were split up into small units that were unable to concentrate into any strong striking forces. Nevertheless the Norwegian Navy had some influence over the following campaign, especially around Bergen and north of Trondheim.
On the day of invasion the navy didn't accomplish much. The patrol vessels usually made their duty as planned and reported the ships passing by. The information was however to imprecise and the general situation too confused to allow the headquarters to act quickly. Thus the main units of the navy usually took no part in the first actions. The two armoured ships in Narvik were quickly sunk by the German destroyers. At Trondheim the naval units were inactive while the German invasion fleet passed by and occupied Trondheim and the coastal fortress Agdenes. At Bergen the event was much like in Trondheim except that a mine layer did lay out a small mine field in the sea lane to Bergen. At Stavanger a destroyer did sink a German cargo ship before getting sunk by German aircrafts. At Kristiansand the naval units were inactive while the coastal fortress fended off repeated attempt by the German invasion fleet to reach the harbour. When the Germans finally managed to break through, the naval units surrendered together with the coastal fortress. In Egersund the torpedo boat Skarv was taken completely by surprise by the Germans. In Oslofjord, the only naval action in the initial stage was when Olav Tryggvason and the mine sweeper Rauma successfully fended of the German force aimed at the main Norwegian naval base. This was however to no avail as the base surrendered to a small infantry force, at the threat of bombardment of the city from air and heavy cruisers.
The situation for the Norwegian Navy after the morning of the 9th of April was thus that the main bases had fallen to the aggressors, most of the bigger units of the fleet were lost and the rest of the units were scattered outside the bridgeheads held by the Germans.
After the initial landings the German Navy withdrew most of their bigger ships to Germany, leaving behind smaller units, like minesweepers (R-boote) and MTBs (S-boote). Exceptions were the ten destroyers trapped in Narvik and two destroyers at Trondheim. There were also a few bigger vessels, like the artillery training ship Bremse in Bergen. Thus the difference in force were no longer as fundamental as it had been at first. Along the south coast (1.S.F.D area) a small force gathered in the Larvik-Sandefjord area. They did not dare to act in the face of German air-force, and acted as a force in being, waiting for a British intervention that never materialized, while the Germans picked their bases one after another. In the Bergen area most of the surviving Norwegian units were located. Here they were a valuable part of the Norwegian defences around the German held city of Bergen, securing the north flank in Sognefjord and the south in Hardangerfjord. The German air-force was a major nuisance here as well, but not decisive. After a number of small actions between old Norwegian torpedo boats and German S-boote and other smaller units, the Germans finally managed to break the Norwegian resistance in Hardangerfjord, quickening the collapse of the Norwegian land forces defending Moss. Hopefully I'll be able to write about a few of this actions at some time.
The most valuable task of the Norwegian navy during the war, was perhaps the patrolling made by various patrol vessels, preventing sea transport to, and supply of, the German bridgeheads and advanced columns, along the west coast and in northern Norway. A number of German cargo ships were caught by the Norwegian patrol vessels during the war.
Organization of the Norwegian marine and a listing of all marine units
List of all ships and boats in the Norwegian Navy
Ranks of Norwegian navy