Katsuragi-class corvette

The Katsuragi class (葛城型スループ) was a three-ship class of composite hulled, sail-and-steam corvettes of the early Imperial Japanese Navy.

Design and description
The Katsuragi vessels were designed as iron-ribbed, wooden-hulled, three-masted barque-rigged sloops-of-war, with a basic design based on experience gained in building JAPANESE CORVETTE Kaimon and JAPANESE CORVETTE Tenryū sloops. The planking was a combination of teak and native keyaki wood. The Katsuragi-class ships had an overall length of 61.37 m, a beam of 10.76 m, and a normal draught of 4.65 m. They displaced 1502 LT at normal load. The crew numbered about 231 officers and enlisted men.

Propulsion was by a coal-fired double-expansion reciprocating steam engine with six cylindrical boilers driving a double screw. The engines were rated at 1600 ihp, and designed to reach a top speed of 13 kn.

The Katsuragi-class ships were armed with two Krupp 170 mm Krupp breech-loading guns, five 120 mm Krupp breech-loading guns, one 80 mm Krupp QF gun, four quadruple 1-inch Nordenfelt guns and 380 mm torpedo tubes. A major improvement over previous Japanese corvette designs was the use of recessed gun ports, which allowed the two forward guns to fire on a forward arc instead of only on a broadside.

The design for the Katsuragi-class ships was by British-educated Japanese naval architect Sasō Sachū, director of the Yokosuka Naval Arsenal. Two of the three vessels (Katsuragi and Musashi) were built at Yokosuka, and one (Yamato) by built by the private-contractor, Onohama Shipyards in Kobe (a predecessor of Hitachi Zosen Corporation). In late 1900, the ships were extensively refitted, during which time their sail rigging was removed, and armament changed to eight QF 2.5 pdr guns and six quadruple 1-inch Nordenfelt guns. The torpedoes were upgraded from 15 inch to 18-inch torpedo tubes. However, during the Russo-Japanese War, the ships were regarded as obsolete and were assigned as guard ships in ports in the Japanese home islands.

In 1907, the armament was changed again, this time to four 3-inch and two 2.5-inch guns, and the ships were reclassified as survey ships or as a second-class coastal patrol vessels. Katsuragi was removed from the navy list on 11 April 1913, and Musashi on 1 April 1928. Yamato was removed from the navy list 1 April 1935, but survived as a floating prison until the end of World War II.