They had fixed turrets mounting 240 mm (9.4 in) guns and someone on the defense staff realized that they could be destroyed while retreating because none of the ships could fire to their rear.

[2] The Hildur-class ships had two horizontal twin-cylinder steam engines, each driving a single propeller.

The engines produced a total of 155 indicated horsepower (116 kW) which gave the monitors a maximum speed of 8 knots (15 km/h; 9.2 mph).

[3] Folke was equipped with one 240-millimeter (9.4 in) M/69 rifled breech loader, mounted in a long, fixed, oval-shaped turret that faced to the rear.

[1] Folke had a complete waterline armor belt of wrought iron that ranged 38 to 76 millimeters (1.5 to 3.0 in) thick from front to rear.