As Army Group North advanced through the Baltic states, the Soviets were forced to make a number of sea evacuations along the coast. The German and Finnish navies tried to interfere with these evacuations by laying mines in the approaches to and from the seaports. A total of 3,000 mines were laid outside Tallinn to interfere with the large-scale evacuation from that city. A fleet of 160 ships evacuated 28,000 personnel and 66,000 tons of matériel. This evacuation began on August 27, 1941, despite heavy and almost constant attacks by German aircraft and artillery. The Soviet ships ran into the heavily mined area near Cape Jumida on August 28 while under attack by Finnish and German torpedo boats. Sixty-five of the 160 ships were lost and a large number damaged. Personnel losses were heavy with 16,000 perishing.
Both the German and Finnish navies suffered serious losses on September 14. Three German minesweepers exploded in Helsinki harbor due to unknown causes. On the same day, the Finnish coastal defense ship Ilmarinen struck a mine and sank southwest of Hanko with the loss of 271 sailors.
The Soviets evacuated the islands off Koivisto before the Gulf of Finland froze. These islands would have been very difficult to defend after the ice became thick enough to support troops. The Finns occupied the islands in early November.
Things remained relatively quiet at the leased Soviet naval base at Hanko, which had begun to lose its importance for the Soviets in view of the northward progress of Army Group North. The Soviets did not have the strength to undertake any offensive operations and the Finns confined themselves to keeping the place blockaded from both land and sea. The Soviets decided to evacuate Hanko when the Gulf of Finland began to freeze. They may have assumed that the Finns had delayed any offensive operations against Hanko pending the freeze, which would prevent Soviets from sending reinforcements.
A strong Soviet naval force from Kronstadt Bay set out for Hanko on November 3, 1941. They managed to avoid the minefields and brought off the garrison without interference from the Finns who were taken by surprise. Several Soviet ships heading back to Kronstadt Bay struck mines and sank with heavy losses. The Finns occupied Hanko on December 4.
German naval assault units attacked and occupied the Osmussar Islands off the Estonian coast. They also planned to occupy Suursaari Island (Gogland), important for controlling shipping traffic because of its location more or less in the center of the Gulf of Finland east of Helsinki. The operation was postponed because the necessary forces for a continued occupation were lacking.
The plan to occupy the islands in the Gulf of Finland was revived in early March 1942, this time at the urging of Army Group North. The Finns were also eager to occupy Suursaari Island before the ice disappeared from the Gulf. Suursaari was important for the air defense of Finland and in blockading Leningrad. The participation of German troops in the operation became doubtful by the middle of March since the situation in Army Group North’s area did not permit a withdrawal of forces.
Marshal Mannerheim decided on March 17, 1942 to act alone against Suursaari. Forces from the 18th Finnish Division, commanded by Major General Aaro Olavi Pajari, were assembled near Kotka. German participation was limited to air support.
The Finnish attack on Suursaari began at night on March 26 and the island was secured on March 27. Tytaersaari (Bolshoi Tyuters), a smaller island about 20 kilometers south of Suursaari, was also captured on April 1. A German garrison relieved the Finns on Tytaersaari on April 4 and the Soviets chose that time to launch an attack on the island, which was repulsed. This island remained occupied by the Germans, while Suursaari was occupied by the Finns. These difficult operations were carried out quickly and with relatively light losses. Any delay would have made the operations impossible since the ice in the Gulf of Finland lost adequate carrying capacity within a few days.
The Finnish Air Force was seriously outnumbered by the Soviets but was nevertheless very successful in its operations. Finnish fighter planes contested Soviet air superiority and their pilots showed great ability and courage in numerous air fights. Finnish aircraft gave excellent support to ground operations.
The Finnish anitaircraft artillery forces were stronger and better equipped than they had been in the Winter War. However, their limited size and the vastness of the territory to be defended prevented them from giving adequate protection to some of the cities. For example, an air attack on Helsinki on November 3, 1941, caused severe damage.
The Finnish Air Force had great success over the Gulf of Finland in early 1942. Bitter air battles were fought after the Finnish attacks on Suursaari and Tytaersaari Islands. Finnish fighter planes downed twenty-seven Soviet planes on March 28, 1942. During the entire war, Finnish aircraft and pilots proved themselves superior to their Soviet opponents.
The German Luftwaffe had the dual missions of supporting the fight for Leningrad, and at the same time, conducting air warfare in the arctic. German bombers from the 5th Air Fleet made numerous attacks on Soviet installations along the Murmansk Railroad, trains, the port of Murmansk, and Soviet installations and bases on the Rybachiy Peninsula. The 1st Air Fleet, supporting Army Group North, also flew numerous missions in support of Finnish operations in the Lake Ladoga area and to interdict the Soviet supply route after Lake Ladoga froze in December. It was bombed regularly by German planes.
The Germans, because of their own stretched resources, made frequent requests for Finnish Air Force support in the spring of 1942. The 1st Air Fleet requested Finnish assistance in providing air cover over the Gulf of Finland on April 5. On the same day the 5th Air Fleet (in Norway, and responsible for supporting operations of German forces in Finland) requested that the Finnish Air Force support Army of Lapland operations. The Finns were not able to meet these requests but it revealed to them the fact that the Luftwaffe was overextended as a result of the Soviet winter offensive.
The Finns turned down a request by the Germans to station two bomber groups at the Malmi Airport near Helsinki. The reason for the German request was that stationing the aircraft there would allow them to approach Leningrad from the north. Mannerheim turned down this request for political reasons and to avoid exposing the Finnish capital to Soviet air attacks. The Finns offered the Germans the use of Utti Airport, just east of the town of Kuovola and around 80 kilometers northeast of Helsinki. The 1st Air Fleet used Utti until the end of October 1942.
The 5th Air Fleet had begun an extensive program to enlarge and strengthen its ground support elements in Finland. This program put a strain on the Finnish economy because of the large requests for building material. The Finns were engaged in large programs to fortify the areas they had captured and the German requests competed with these projects.
Lieutenant General Jarl Fritjof Lundquist, the commander in chief of the Finnish Air Force, a very outspoken individual with a growing skepticism about the outcome of the war, gave the German liaison officer at his headquarters an earful about the constant German changes in plans and their extravagant demands on the Finnish economy:
The Finns are beginning to be fed up with being led by the nose by the Germans. Considering the large ground organization needed by the Luftwaffe, we Finns cannot adapt ourselves every four weeks to another plan…. For the time being we shall do nothing but wait and see how the situation develops.23
Lundquist let it be known that the Finns were becoming leery about German ability to encircle Leningrad and thus provide the Finns some security.
General Hans-Jürgen Stumpff, commander of the 5th Air Fleet in Norway, came to the Finnish headquarters in Mikkeli on January 17, 1942, primarily to discuss operations against Belomorsk with the Finnish General Staff and General Lundquist. Both General Stumpff and General Erfurth, who also attended the meetings, came away with the distinct and uneasy impression that the Finnish officers were unusually reserved and noncommittal on all issues.24