[1] The first attempt to breach Sölfverarm's position happened on 18 July when 6 Russian gun sloops unsuccessfully tried to get past the Swedes in what has become known as the Battle of Tallholmen.

[1] Sölfverarm continued to strengthen his defenses and constructed an artillery battery on an island in the middle of the narrow passage.

In addition to naval assets, the Russians had 1 six-gun and 1 four-gun batteries, 2 field guns, and six companies of infantry in support.

Though several of their gun sloops were forced to withdraw from the battle line, the Swedes managed to beat back the initial Russian attack.

[2] While the naval battle was being fought at Sandöström, another Swedish unit was performing landing operations on the island of Kimito.