of December, impeding the movement of warships; by mid-winter, only ice breakers and submarines could still move. The other reason for low naval activity was the nature of Soviet Navy forces in the area. The Baltic Fleet was a coastal defence force which did not have the training, logistical structure, or landing craft to undertake large-scale operations. The Baltic Fleet possessed two battleships, one heavy cruiser, almost 20 destroyers, 50 motor torpedo boats, 52 submarines, and other miscellaneous vessels. The Soviets used naval bases in Paldiski, Tallinn and Liepāja for their operations. The Finnish Navy was a coastal defence force with two coastal defence ships, five submarines, four gunboats, seven motor torpedo boats, one minelayer and six minesweepers and at least 5 icebreakers. The two coastal defence ships, and , were moved to harbour in Turku where they were used to bolster the air defence. Their anti-aircraft guns shot down one or two planes over the city, and the ships remained there for the rest of the war. At 18 January, Finnish armed icebreaker Tarmo was severely damaged at Kotka, received 2 bombs from a Soviet bomber with 39 Finnish troops killed in action. As well as coastal defence, the Finnish Navy protected the Ålandish and Finnish merchant vessels in the Baltic Sea. Soviet aircraft bombed Finnish vessels and harbours and dropped mines into Finnish seaways. Still, only five merchant ships were lost to Soviet action. World War II, which had started before the Winter War, proved more costly for the Finnish merchant vessels, with 26 lost due to hostile action in 1939 and 1940. Coastal artillery Finnish coastal artillery batteries defended important harbours and naval bases. Most batteries were left over from the Imperial Russian period, with guns being the most numerous. Finland attempted to modernise its old guns and installed a number of new batteries, the largest of which featured a gun battery on the island of Kuivasaari in front of Helsinki, originally intended to block the Gulf of Finland to Soviet ships with the help of batteries on the Estonian side. The first naval battle occurred in the Gulf of Finland on 1 December, near the island of Russarö, south of Hanko. That day, the weather was fair and visibility was excellent. The Finns spotted the Soviet cruiser and two destroyers. When the ships were at a range of , the Finns opened fire with four coastal