[7] A part of the Swedish battlefleet, 12 ships of the line and 5 frigates under the command of Prince Charles, Duke of Södermanland, had set sail from Karlskrona on 9 June 1788.

While Prince Charles had overall command of the fleet, he was assisted by Admiral Anton Johan Wrangel (the younger) and had the experienced naval officer Lieutenant Colonel Otto Henrik Nordenskjöld as his flag-captain.

Already before the war had started, the fleet had intercepted a small Russian squadron of 3 ships of the line and 4 frigates headed for Denmark and demanded of these to salute his flag, which was in direct contradiction of the treaties of 1743.

[8] After being notified that a state of war was in effect on 7 July, the Swedish fleet headed for Helsingfors to wait for reinforcements.

Before reaching their destination, the Swedes intercepted and promptly captured two Russian frigates, which were unaware of the war and got caught by surprise.

Already on 4 July 1788, Admiral Samuel Greig moved his fleet of 12 ships of the line, 5 frigates and 3 cutters out of Kronstadt.

As most of the sailors had been recruited shortly beforehand and had no experience in maritime matters, Greig made efforts to exercise his subordinates to improve their skill levels.

The Russian fleet responded in kind but the turn had reversed their intended battle line and caused some disorder in the vanguard which forced four ships to leave the others behind.

[15] The Russian fleet under Admiral Greig had been unable to chase the Swedish and was forced to lay anchor at the site of the engagement.

The situation was aggravated when a small Russian squadron under James Trevenen blockaded Hangö, cutting the coastal sea route and causing considerable problems for Swedish material deliveries from Sweden.

[17] Admiral Greig hurried the repairs of the Russian fleet and constructed a forward base on the island of Seskar to accomplish this.

It encountered a Swedish squadron which had been tasked with investigating the status of the Russian fleet outside of Sveaborg in the early hours of 6 August.