Japanese Cruiser Itsukushima - Design

Design

Itsukushima differed from her sister ship Hashidate primarily in that her windows were square instead of rectangular, and in that Hashidate had a stronger engine.

Itsukushima had a steel hull with 94 frames constructed of mild steel, and a double bottom, divided into waterproof compartments, with the area between the bulkheads and armor filled with copra. The bow was reinforced with a naval ram. The vital equipment, including boilers and ammunition magazines, were protected by hardened steel armor, as were the gun shields. The main armament consisted of one breech-loading 320-mm Canet gun mounted in the bow of the ship, which could fire 450-kg armor-piercing or 350-kg explosive shells at an effective range of 8000 meters. The maximum rate of fire was two rounds per hour, and the ship carried 60 rounds. Secondary armament consisted of eleven QF 4.7 inch Gun Mk I–IV Armstrong guns, with a maximum range of 9000 meters and maximum rate of fire of 12 rounds/minute. Ten were mounted on the gun deck, five to each side, with the 11th gun located on the upper deck of the fantail. Each gun was equipped with 120 rounds. Tertiary protection was by six QF 6 pounder Hotchkiss mounted in sponsons on the upper deck, with a maximum range of 6000 meters and rate of fire of 20 rounds/minute. Each gun had 300 rounds. In addition, eleven QF 3 pounder Hotchkiss were mounted at various locations, with range of 2200 meters rate of fire of 32 rounds/minute and 800 rounds per gun. Each ship in the class also had four 356-mm torpedo tubes, three in the bow and one in the stern, with a total of 20 torpedoes carried on board. The weight of all of this weaponry led to the design becoming dangerously top-heavy, and armor was sacrificed in an effort to reduce weight.

The ship was driven by two horizontal triple expansion steam engines. However, the design had problems with seaworthiness, and the design speed was seldom attained in operation.