The purpose of the coastal defence ships was to prevent landing operations and naval blockades that threatened vital sea trade. Thanks to the construction of vast defensive systems during the czarist era, Finland had strong coastal artillery in permanent positions. These defenses were to be supplemented with minefields in times of unrest. One of the main purposes of the navy was to buy time for ground forces to deploy to the islands in the Archipelago. In these confined spaces, coastal defence ships armed with 254 mm main artillery would have been a tough opponent for any ship of the era.