Battle of Someri The Battle of Someri was a battle in the Gulf of Finland during World War II on 8 – 9 July 1942 , between the Soviet Union and Finland . Starting as a modest operation to clear a Finnish observation post from a small island , it became one of the largest surface ship engagements in the Baltic theater . Background . During the Russo - Finnish Winter War ( 1939 – 40 ) , Soviet forces captured several Finnish islands in the eastern Gulf of Finland . In March 1940 these were ceded to the Soviet Union in accordance with the Moscow Peace Treaty . The Soviets occupied some of them with small garrisons . When the Continuation War began in June 1941 the islands were generally ignored ; in autumn 1941 , however , the Finnish Navy attempted to occupy the small , rocky island of Someri ( now Sommers , Russia ) , mistakenly thinking it had been abandoned by the Soviets . Coming under fire from the defenders , the small Finnish landing force hastily withdrew . Over the next few weeks the Finns shelled and bombed the island several times in hopes of forcing the Soviet garrison to depart . Finally in December 1941 , as Soviet forces evacuated Hanko and several other islands in the Gulf of Finland , the garrison on Someri was withdrawn to Moshchny Island . Finnish coastal forces occupied the island soon after . It proved to be a good position for observing Soviet movements in the area . Order of Battle . Finnish . The 100 - man Finnish garrison on the island was equipped with two 75 mm field guns , a few 45 mm anti - tank guns and 20 mm automatic cannons , and several machine guns . During the battle the garrison was reinforced with an additional 100 men . The Finnish Navy deployed 3 gunboats ( " Turunmaa " , " Hämeenmaa " , and " Uusimaa " ) , 2 minelayers ( " Riilahti " , and " Ruotsinsalmi " ) , 6 VMV class patrol boat s and 4 motor torpedo boats to the area . In addition , several small minesweepers were used to carry ammunition for the gunboats and reinforcements for the garrison . The Finnish Air Force supported the naval forces and sortied several flights of fighters ( Brewster F2A Buffalo and Fokker D . XXI ) and bombers ( Bristol Blenheim and Dornier Do 17 ) to the area . German . Germany sent two M class minesweepers ( " M - 18 " and " M - 37 " ) and an older minesweeper / tender , the " Nettelbeck " , to support Finnish forces . A converted civilian ship - SAT " Ost " ( Schwere Artillerie Trager - Heavy Artillery Trawler ) - was also moved to the area to counter Soviet naval artillery , which was believed to be superior to that of the Finnish and German ships . Soviet . The original Soviet landing force consisted of 256 lightly - armed men ( later reinforced by an additional 57 men from Moshchny Island ) supported by a force of ~ 30 patrol ( MO ) and motor torpedo ( TKA ) boats . When the initial landing failed to surprise or overpower the Finnish defenders , more naval forces were deployed to the area . These consisted of two large minesweepers ( " T - 205 " , " T - 207 " ) , the Uragan class guard ship " Burya " ( " Буря " ) , the auxiliary gunboat " Kama " ( " Кама " ) , and additional patrol and motor torpedo boats . The Soviet Air Force repeatedly attacked Finnish ships and positions on the island with Il - 4 ( DB - 3F ) & Pe - 2 bombers and Il - 2 ground attack aircraft protected by I - 153 , Yak - 1 and LaGG - 3 fighters . Battle . Shortly after midnight , on 8 July 1942 , Soviet aircraft bombed Someri , causing minor damage , after which 26 Soviet patrol and motor torpedo boats approached the island . Heavy firing erupted as the Soviet landing force moved ashore . Though considerably outnumbered , the heavily - armed Finns , fighting from well - prepared positions , drove off many of the boats and contained the landing force in the eastern half of the island . Alerted by the garrison , a sizable portion of the Finnish Navy , as well as several flights from the Finnish Air Force , came to Someri ' s defense . They were able to clear the immediate vicinity of the island , but , as they drove off Soviet motor torpedo boats , repelled attacking Soviet aircraft , and bombarded Soviet troops ashore , the Finnish gunboats ' ammunition stores dwindled rapidly , and they were forced to depart for resupply . Finnish forces supported by a newly arrived German minesweeper managed to bring reinforcements to the island before noon , but once again , repeated Soviet MTB and air attacks depleted the ammunition stores on the gunboats . Soviet artillery ships started their approach and forced the Finnish ships to depart for resupply , which provided an opening for the Soviet boats to approach and in turn reinforce their landing force . Returning Finnish gunboats drove the Soviet boats away from the island before nightfall . On shore , the Soviet landing force was pushed into a small corner on the east end of the island , but managed to hold its positions there . During the night Soviet ships shelled from a distance , while a few Soviet boats managed to reach the island under cover of darkness . On the morning of 9 July most of the naval activity came to an end as Soviet boats withdrew , though the larger Soviet ships continued shelling the area . Finnish forces , reinforced by the German SAT " Ost " , armed with a single 152mm gun - heavier than any guns aboard the Soviet ships - attempted to drive them away , and the Soviet ships withdrew under cover of smokescreens . This proved to be the final surface action of the battle . During the morning the last Soviet pockets of resistance had been cleared from the island . There were several more Soviet aerial attacks , but no further landing attempts . Results . Finnish and German forces reported sinking over 16 Soviet patrol and motor torpedo boats , and credited the Finnish Air Force with sinking a Soviet auxiliary gunboat ; Soviet reports , on the other hand , claimed that several large vessels ( Finnish gunboats or large German minesweepers ) had been sunk . The relatively weak performance of the Finnish gunboats showed how badly outdated their main armaments had become , and prompted the Finnish Navy to upgrade them ; however , due their old age , weak hulls , and lack of resources , only " Hämeenmaa " and " Uusimaa " were modified before the end of the war . In September 1944 , under the terms of the armistice ending the Continuation War , Someri ( now Sommers ) reverted to Russian sovereignty .