|Builder:||Motala Verkstad, Norrköping|
|Displacement:||460 metric tons (450 long tons) (deep load)|
|Length:||39.78 m (130 ft 6 in)|
|Beam:||8.72 m (28 ft 7 in)|
|Draft:||2.7 m (8 ft 10 in)|
|Installed power:||155 ihp (116 kW)|
|Propulsion:||2 shafts, 2 steam engines, 2 boilers|
|Speed:||8 knots (15 km/h; 9.2 mph)|
HSwMS Folke was the last of the seven Hildur-class monitors built for the Swedish Navy in the mid-1870s. Unlike her sisters, her gun turret was fixed to the rear. The ship was placed in reserve in 1919 and ultimately sold in 1942.
Design and description
The Hildur-class monitors were designed by Lieutenant John Christian d'Ailly, from a proposal by John Ericsson, for the defense of Lake Mälaren and the Stockholm archipelago. 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. Folke was designed to protect her sisters in that situation as her turret was fixed to the rear.
Folke was 39.78 meters (130 ft 6 in) long overall and had a beam of 8.72 meters (28 ft 7 in). She had a draft of 2.7 meters (8 ft 10 in) and displaced 460 metric tons (450 long tons). Her crew numbered 48 officers and men. The ship had a rudder at bow and stern.
The Hildur-class ships had two horizontal twin-cylinder steam engines, each driving a single propeller. Their engines were powered by two cylindrical boilers. 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). The ships carried 23–25 metric tons (23–25 long tons) of coal.
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. The gun weighed 14,670 kilograms (32,340 lb) and fired projectiles at a muzzle velocity of 397 m/s (1,300 ft/s). At its maximum elevation of 7.5° it had a range of 3,500 meters (3,800 yd). The ship also mounted two 75-millimeter (3.0 in) guns.
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. The deck was 19 millimeters (0.7 in) thick. The face of the gun turret was protected by 418 millimeters (16.5 in) of armor, while its sides were 356 millimeters (14.0 in) thick. The conning tower protruded from the top of the turret and was protected by 254 millimeters (10 in) of armor.
Construction and service
Folke was launched in 1875 by Motala Verkstad at Norrköping. She was decommissioned in 1919 and was eventually converted into a heating plant for mothballed submarines. The ship was sold in 1942 for conversion to a barge.
- Harris, pp. 30–32
- Harris, pp. 30–31
- Gardiner, p. 362
- Bojerud, p. 177
- Harris, p. 32
- Harris, pp. 31–32
- Bjoerud, Stellan (1986). "Monitors and Armored Gunboats of the Royal Swedish Navy, Part 1". Warship International. Toledo, Ohio: International Naval Records Organization. XXIII (2): 167–80. ISSN 0043-0374.
- Gardiner, Robert, ed. (1979). Conway's All the World's Fighting Ships 1860–1905. Greenwich: Conway Maritime Press. ISBN 0-8317-0302-4.
- Harris, Daniel G. (1994). "The Swedish Monitors". In Roberts, John. Warship 1994. Annapolis, Maryland: Naval Institute Press. pp. 22–34. ISBN 1-55750-903-4.