Hildur-class monitor
The Hildur-class monitors consisted of seven monitors built for the Swedish Navy in the 1870s. They were sold in 1919 and most were converted into fuel oil barges. One such ship,, has been converted into a museum ship.
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. The ships were long overall and had a beam of. They had a draft of and displaced. The crew of the first two monitors, Hildur and Gerda, numbered 42 officers and men, the others had 48-man crews. Hildur and Gerda only had a stern rudder, the other had rudders at bow and stern. Bow rudders were fitted to the older ships when they were reconstructed.The Hildurs had a pair of two-cylinder horizontal-return connecting-rod steam engines, each driving a single propeller using steam from two cylindrical boilers. The engines produced a total of in the first two ships and in the later ones which gave the monitors a maximum speed of. The ships carried of coal.
The monitors were equipped with one M/69 rifled breech loader, mounted in a long, fixed, oval-shaped gun turret. The gun weighed and fired projectiles at a muzzle velocity of. At its maximum elevation of 7.5° it had a range of. The gun and its turret in Folke were oriented to the rear. Hildur and Gerda were rearmed with a quick-firing gun as well as three quick-firing guns 1890; the other were similarly rearmed later in the 1890s or the early 1900s.
Most of the ships of the Hildur class had a complete waterline armor belt of wrought iron that was thick with a deck. Bjorn and Ulf had a belt while Folkes belt ranged from forward to 76 mm aft. The face of the gun turret was protected by of armor, while its sides were thick. The conning tower protruded from the top of the turret and was protected by of armor.