First Battle of Svensksund The First Battle of Svensksund , also known as the First Battle of Rochensalm from the Russian version of the Finnish : " Ruotsinsalmi " , was a naval battle fought in the Gulf of Finland in the Baltic Sea , outside the present day city of Kotka , on August 24 , 1789 during the Russo - Swedish War ( 1788 - 1790 ) . Order of battle . Swedish fleet at Svensksund consisted of 1 light , shallow draft , frigate , 6 turuma , 1 hemmema , 3 udema , and 1 pojoma archipelago frigate , 20 gun sloops , 4 mortar longboats , 4 cannon longboats and 5 galley s . Without taking account the auxiliaries and transports the fleet had 5000 men . Swedish strength had been depleted since it had to defend the whole length of the coast since the open sea fleet had failed to defeat Russian fleet at Öland and was therefore unable to clear Porkkala region of Russian ships . Russian coastal fleet consisted of a frigate , 8 xebec s , 5 brig s , 3 bomb vessel s , 18 galley s , 29 half - galley s , 12 gun sloops and 3 cutters with total of 12000 men without taking auxiliaries into account . In addition to the coastal fleet Russians were also supported by a squadron from open sea fleet commanded by Ivan Balle consisting of amongst other ships 3 frigates , 7 xebecs , and two dozen smaller ships . First phase of the battle . Swedish fleet was well aware of the Russian numerical superiority and started creating blockades to the narrow passages on 23 August by scuttling some ships . This operation did not succeed as expected since the scuttled ships failed to blockade all the narrow passages . Action between main elements of Swedish archipelago fleet and Russian squadron led by Balle started at 10 : 00 on 24 August and the artillery duel continued for six hours before initial Russian attack from the south was beaten back with Russians losing three ships captured and several other badly damaged . Second phase of the battle . Russian coastal fleet had meanwhile approached from the east and was probing its way through the Swedish blockade under fire . Decisive event happened at 16 : 00 when right wing of the Russian coastal fleet led by Giolio Litta managed to penetrate the narrow passage between Majasaari ( Koiromsari ) and Tiutine which had not been blockaded by the Swedes . Battle which had started well for the defender now turned into attackers favor . Russian attack forced the Swedish ships which had been guarding the blockade to withdraw making it possible to clear the obstacles . Russians captured turuma " Sällan Värre " which had run aground while defending the blockades and hemmema " Oden " which had come to its aid . After it became clear that Russians had beaten the blockade Swedish archipelago fleet withdraw into the safety of fortress at Svartholm . During the withdrawal several other ships were lost , turuma " Björn Järnsida " - which had been the flagship of Ehrensvärd at the start of the battle - run aground and after fighting nearly to the last man it had to struck its colors . Frigate " af Trolle " and turuma " Ragvald " were also captured along with 1 gun sloop . Swedish auxiliaries and transport vessels trapped to the north of island of Kotka were burned to prevent their capture . Aftermath . Swedish losses in total were 3 turuma archipelago frigates , 1 hemmema archipelago frigate , 1 light frigate , 1 galley , 1 half - galley , 1 schooner , 9 gun sloops and 30 transport and auxiliary vessels . Total number of men died , wounded or captured during the battle was roughly 1500 in addition to a field hospital formed for 500 sick which Swedes were unable to evacuate in their hasty withdrawal . Russian losses were in the end only 1 galley and 1 gun sloop , both of which blew up . Russians managed to recapture all ships from Balle ' s squadron that Swedes captured early in the battle . Total number of casualties ( KIA , WIA and captured ) was 1100 . Though Russians had gained a clear victory they had failed to inflict decisive defeat on the Swedish archipelago fleet . One of the reasons for this was the delayed attack by Nassau - Siegen which allowed Swedes to defeat Ivan Balle ' s squadron . Inactivity of the initially beaten Balle ' s squadron during the later phase of the battle allowed most of the Swedish fleet to reach the safety of Svartholm fortress and regroup for later battles . The small galley force commanded by Giulio Litta that was able to navigate the shallow yet unobstructed narrow between Tiutine and Koiromsari was crucial factor in Russian success at Svensksund . There are several reasons for the Swedish defeat . Ehrensvärd ' s preparations for defense were hampered by King Gustav III ' s opposition to his plan which delayed the construction of the obstacles in the straits opening towards Frederikshamn which made it possible for the Russians to clear them so quickly . On the other hand Ehrensvärd ' s decision not to blockade the narrow between Tiutine and Koiromsari due to his belief that it was too shallow to navigate was to prove a crucial error . Furthermore the area had been improperly sounded as proven by the several ships that run aground during the battle even though Svensksund had been selected as a battleground by the Swedes far in advance of the fight . Yet had the king allowed Ehrensvärd to withdraw to Svartholm after defeating Balle ' s squadron like Ehrensvärd had planned in the first place Swedes would have won a solid victory at Svensksund already in 1789 . When King Gustav III gave the order to fight against the main force of the Russian coastal fleet he had already been made aware that fleet was running low on ammunition . Swedish performance was also greatly affected by the successful Russian blockade at Porkala which kept 2 archipelago frigates , roughly 20 galleys and several gun sloops and yawls away from the Svensksund still in August 1789 .