This was a Soviet combined air and sea operation against the German convoy routes round the extreme north of German-occupied Norway (10/28 June 1944).
The operation started with the laying of a minefield near Rolfsøy by the submarine L-20, which also undertook a reconnaissance and laid a second minefield on 28 June. S-14, S-104, M-200 and M-201 were positioned to attack any German naval units which tried to intervene.
On 15 June the first German summer convoy from Kirkenes to Petsamo, supported by a strong escort and aided by a succession of smokescreens, got through to its destination without loss despite attacks by Soviet motor torpedo boats and warplanes. On 15 June, off Hammerfest, a Soviet reconnaissance aeroplane spotted a German convoy of 10 transports escorted by M 31, M 35, M154, M 202 and M 252 of Korvettenkapitän Erich Klünder’s 5th Minensuch-Flottille, R 202, R 160, R 223, V 6102, V 6107, V 6110, V 6722, V 6111, V 6725, UJ 1220, UJ 1209, UJ 1219, UJ 1211 and UJ 1212.
The convoy was reported on the evening of 16 June by reconnaissance aircraft in Svaerholthavet. On 17 June M 35, UJ 1220 and UJ 1209 drove off the submarine M-200. In attacks by Ilyushin Il-2 warplanes of the 46th Ground Attack Regiment, the 7,419-ton freighter Florianopolis was hit, and Ilyushin Il-4 torpedo bombers sank the 1,610-ton Dixie. The mines laid by Soviet motor torpedo boats on the convoy’s route off Kirkenes were cleared by motor minesweepers. Soviet bombers made attacks on the convoy and damaged the 1,912-ton freighter Marga Cords. On 16 June M-201 again hit the wreck of the freighter Natal off Makkaur.
A return convoy consisting of five freighters, six patrol boats, five submarine chasers and two motor minesweepers, which had departed Kirkenes on 19 June, was located by Soviet air reconnaissance to the south of Vardo shortly after 24.00 on 20 June during this period of uninterrupted daylight. The submarine M-200, which shortly after this was spotted by a Heinkel He 115 patrol floatplane as it fired, was driven below the surface by UJ 1209, UJ 1219, UJ 1220 and UJ 1222. Relentlessly depth-charged, the submarine nonetheless managed to escape. An attempted attack by S-14 off the Syltefjord was frustrated by the intervention of a Blohm und Voss Bv 138 flying boat. After some of the freighters had departed the area, the submarine S-104 attacked what was left of the convoy, namely Reinhardt L. M. Russ and R 159, R 173, V 6107, V 6111, NKi 08, NKi 12, UJ 1211 and UJ 1209, off Tanafjord and sank UJ 1209. An attack by M-201 was not seen by the German ships.
On 22 June Il-2, Bell Airacobra and Curtiss Kittyhawk fighter-bombers attacked a small convoy near Vardo and damaged the gun ferry AF 39.
On 27 and 28 June Soviet bomber units, covered by fighters, attacked shipping in Kirkenes, and during this attack the 717-ton freighter Herta and Florianopolis were set on fired and soon burned out. Of a six-freighter convoy on passage from Kirkenes to Petsamo, escorted by Kapitänleutnant Heuser’s 7th Räumboots-Flottille and Kapitänleutnant Rössger’s 21st Räumboots-Flottille, the 989-ton Vulkan was sunk by the fire of coastal batteries and the 992-ton Nerissa was sunk by a motor torpedo boat on 28 June.