Fighting the U-boats
Norwegian Naval forces
The Norwegian Navy at the beginning of the war in 1940 consisted of 1 minelayer, 1 escort and 9 submarines. Later the British gave to Norwegians 6 destroyers, a few corvettes and 3 submarines, as the Norwegians lost almost all their fleet during the German invasion when the Germans captured 2 battleships, 4 submarines (3 were scuttled by their own crews) and other smaller vessels.
One submarine, B-1, managed to escape and sailed to England. The Norwegian Navy participated in many operations in the North Sea, the Atlantic and the Arctic Ocean.
Worth to be mentioned is that Norway had the oldest battleships during WWII, the Harald Haarfagre and Tordenskjold were build in 1897 and used as training hulks. They also had 2 coast defence vessels (Eidsvold and Norge). The former 2 were captured by the Germans while the others were sunk at Narvik on April 9, 1940 during the invasion of Norway with the loss of 276 men (105 survivors).
Almost the entire strength of the Royal Norwegian Navy was dedicated to the Battle of the Atlantic. Only two submarines and a flotilla of motor torpedo boats (MTBs) were not employed in the anti-submarine war.
Norwegian Naval successesThe Norwegian submarine Ula sank with a spread of 4 torpedoes the U-974 on 19 April, 1944 near Karsmund.
It has been reported that a few U-boats were sunk by mines near Norway laid by Norwegian vessels (I have no U-boat numbers to match this with though).
Norwegian Naval lossesThe Norwegian destroyer Bath (formerly British, ex "USS Hopewell" 1060 tons) was sunk by U-204 on 19 August, 1941 near the Irish coast.
The Flower class corvette Montbretia (ex br. Montbretia, 925 tons) was sunk by U-624 on 18 December, 1942 in the North Atlantic.
All of these boats, with the exception of B-6, were scuttled by the Germans after being found to be unsuitable for training or any other purpose.
Books dealing with this subject include
Den norske marines bevoktningsfartøyer under første verdenskrig. Wilmar, Atle, 2009.