Psilander commanded a ship-of-the-line in the Battle of Køge Bay, becoming Deputy Superintendent of the Royal Navy shipyard in Karlskrona the same year. Promoted to Schoutbynacht and Admiralty Commissioner in 1712, he was also ennobled the same year. Favoured by the King's patronage since the 1704 battle, he was promoted to Vice-admiral and superintendent of Karlskrona shipyard 1714, and full Admiral in 1715. In 1716 he became governor of Gotland. The Swedish island in the Baltic was under increasing threats from the ascending Russian Navy, which was repeatedly launching raids upon it. Psilander's mission was to organize the local population in a homeland defence, but this proved unfeasible when the Russian galley fleet under Admiral Fyodor Apraksin in July 1717 carried out a week-long looting of parts of the island. He then had to devote himself to recruiting personnel and obtaining supplies and tax funds for the King's last military operations.