Baltic Sea operations. The German bombardment of the Polish naval garrison at
Westerplatte (Danzig) on 1 September 1939 was the first act of war in the Baltic and one of the first of the
Polish campaign. German naval forces quickly overwhelmed the small Polish Baltic Navy of fifteen warships, though some managed to escape to the UK and thereafter fought on the British side under the direction of the Polish
government-in-exile in London.
In November 1939, at the start of the
Finnish–Soviet war, the Soviet Baltic Red Banner fleet blockaded Finnish sea communications with Sweden and bombarded the Finnish coast. But otherwise there were no naval operations in the Baltic until the German Navy, as a preliminary to Germany's invasion of the USSR in June 1941 (see
BARBAROSSA), moved 48 small warships into Finnish waters to reinforce its small units already in the Baltic. The German Navy also established a naval base at Helsinki, and laid extensive minefields which caused heavy Soviet losses once the
German–Soviet war had begun. Surface actions during the initial phase of this conflict were confined to skirmishes, but Soviet ships were bombed and their bases seized.
amphibious warfare was mostly confined to the capture and recapture of islands in the gulfs of Riga and Finland, though some small amphibious raids were mounted by Soviet forces behind German lines on the mainland. In September 1941 Hitler formed a Baltic fleet, which included the battleship
Tirpitz, to prevent Soviet ships fleeing to Sweden when
Leningrad fell, but the city remained defiant and the fleet proved to be short-lived as its ships were soon needed elsewhere.
On paper the Soviet fleet was much superior to those opposing it. Besides having its own air arm of 656 aircraft, based on coastal airfields, it had 2 old battleships, 2 cruisers, 19 destroyers, 65 submarines, and numerous smaller craft. But its organization was weak, it was operationally inexperienced, and from the start it seemed paralysed by overcaution. When Finland, though still officially neutral, occupied the Åland Islands on the day the German–Soviet war began ( 22 June 1941), both Soviet battleships were nearby, but neither interfered. Instead, they withdrew to Kronstadt and remained there throughout the war, one being subsequently sunk by air attack.
The Soviet fleet's inactivity can be at least partially explained by its early losses from the minefields the Germans laid before they launched BARBAROSSA. These mounted further when the fleet evacuated Tallinn for Kronstadt and Leningrad in August 1941: 5 destroyers, 3 submarines, 10 smaller warships, and 42 merchant ships were sunk by mines off Cape Juminda, and from that time the Soviet High Command appeared unwilling to risk its larger units.
During 1942 Soviet submarines slipped through the minefields into the Baltic and sank 23 German or Finnish ships, and damaged others. Though ten were lost this was a great improvement on 1941, when they sank only one ship. However, they also sank five Swedish ships, forcing the Swedes to introduce escorted convoys. Because of these operations the Germans laid anti-submarine nets across the Gulf of Finland, and until September 1944 no more Soviet submarines entered the Baltic.
In January 1944 the fleet completed lifting by night 44,000 troops from
Leningrad to a beachhead around Oranienbaum, a considerable feat of
deception as the Germans were led to believe that the troops were being withdrawn not landed. This force then participated in the advance which forced the final withdrawal of the Germans from Leningrad. In March the fleet began clearing the German minefields from the Gulf of Finland. The Germans tried to prevent these operations, but Soviet air superiority caused them heavy losses. In September 1944, the month the Finns changed sides to fight with the USSR (see
armistice), the Germans attempted to sieze the Finnish island of Suursaan (Hogland) in the Gulf of Finland, but were repulsed by Finnish and Soviet forces. The same month Soviet troops began clearing the islands in the Gulf of Riga, the largest
amphibious operations in which the Baltic Red Banner Fleet was involved during the war.
Once the Normandy landings of June 1944 had succeeded (see
OVERLORD), the Germans sent all available surface warships, and even some submarines, into the Baltic to delay the advancing Red Army. Mines dropped by the RAF in the western Baltic hampered this move, but the heavy cruiser
Prinz Eugen and the pocket battleships
Lützow and
Admiral Scheer were employed to cover the German Army's retreat, and German troops were evacuated from besieged Baltic ports. By May 1945 about one million Axis servicemen and 1.5 million refugees had been rescued, the largest evacuation in maritime history, during which 15,000 lives were lost. Most of the deaths were caused by the sinking of three rescue ships, including the
Wilhelm Gustloff, by Soviet submarines. But despite Soviet submarine and air attacks the Germans retained their naval supremacy, and they continued to supply their divisions trapped in the Courland peninsula, enabling them to hold out there until the war ended.
Soviet Second World War naval losses have not so far been published but it has been estimated that its Baltic fleet lost a battleship, 15 destroyers, 39 submarines, 40 minesweepers, and numerous smaller ships. The Finns lost a monitor, 6 minesweepers, 39 merchantmen, and about a dozen smaller ships. Germany lost 12 destroyers, 7 submarines, 67 minesweepers, and 129 smaller warships and landing craft, and 160 merchantmen; their single biggest loss was among their last when the old 13,000-ton battleship
Schlesien was sunk by a mine on 4 May 1945.
