Second Battle of Svensksund

9–10 July 1790, Svensksund, near present-day Kotka

Decisive Swedish victory; the Russian galley fleet destroyed

After the breakout Gustav took the archipelago fleet back to Svensksund, where it anchored in an L-shaped line across the sound, with the bigger ships in the centre and the galleys and gunboats on the wings, sheltered from the rising south-west wind. Nassau-Siegen, eager to finish the Swedes off before they could recover, attacked on the morning of 9 July, the anniversary of Catherine the Great's accession, without waiting for his whole force or for the weather to ease. His ships went in against the wind into a concentrated fire, and as the day went on the heavy sea broke up his line and drove the Russian galleys and frigates onto each other and onto the rocks. The Swedes counter-attacked, and by the next morning the Russians had lost some fifty to eighty vessels, among them about a dozen frigates and xebecs and Nassau-Siegen's flagship Catharina, and some 6,000 men taken prisoner. It was the largest naval battle ever fought in the Baltic and Sweden's greatest naval victory. Five weeks later Catherine agreed to the Treaty of Värälä.