At this point, the main force of the Soviet Baltic Fleet stationed at Leningrad and some in the Kronstadt advanced post were: 2 battleships, Marat
and October Revolution
, 2 cruisers, 2 flotilla leaders, 12 destroyers, 28 MTBs (Motor Torpedo Boats), 35 submarines and several other support ships.
Given the very bad weather situation, the Germans soon detected the Soviet Navy's strategy which consisted of sending its entire fleet of submarines and MTB to try to localize the German ships and damage them with torpedos. This action would also be only possible unti8l the end of the year, before the ice covered that part of the Baltic Sea. The first section of the German flotilla to detect Soviet submarines were the ships stationed at the entrance of the twisted Viborg bay. Captain Harald Netzband of Gneisenau
had ordered some of the destroyers of his flotilla to take position near the small town of Viborg, as previously said to attack the Soviet bombers with their AA artillery, while DD Köln
and four other destroyers remained near the mouth of said bay. It were these vessels that on the 6th December spotted Soviet submarines with their GHG and sonar devices. While one of the four destroyers remained near Köln
, the other three were sent out to attack said submarines with depth charges. Results are unknown since it was imopossible to see any debris coming up to the surface, should any submarine have been hit. Through their radar set in at close range, the destroyers detected also some of the MTB and here they could witness the destruction of at least eight of them, since the Germans could detect the MTB but the opposite was not possible for the Soviets. Visibility at sea level rarily was over 300 meter, on many occasions the German destroyers fired "blind" into the hail and snow, only guided by the radar data (bearing and aproximate range).
This fact led the DKM command at Kiel to speed up the installation of radar sets of the type FuMO 30 Seetakt
aboard the German submarines because with these devices, suited for closer ranges than the radar sets of the destroyers, tracking would become easier. Six of the German submarines belonging to the German flotilla had already these radar devices installed and they began immediately to operate in the Viborg area although operating their 8,8cm guns on the deck was more often than not impossible due to the waves washing the entire decks of the U-boats. Only the smaller 20mm cannons mounted above, on the bridge's level, could safely be operated. And success they had! Another eight MTB could be destroyed before the ice season began; a fact which led the Soviets to drastically diminish their activities on this level.
FuMO 30 antenna installed on an U-Boot