thumb|Turret of , one of the first turret-armed warships
Turret ships were a 19th-century type of warship, the earliest to have their guns mounted in a revolving gun turret, instead of a broadside arrangement.
Background
thumb|[[HMS Prince Albert (1864)|HMS Prince Albert, a pioneering turret ship, built by naval engineer Cowper Phipps Coles.]]
Before the development of large-calibre, long-range guns in the mid-19th century, the classic ship of the line design used rows of port-mounted guns on each side of the ship, often mounted in casemates. Firepower was provided by a large number of guns which could only be aimed in a limited arc from one side of the ship. Due to instability, fewer larger and heavier guns can be carried on a ship. Also, the casemates often sat near the waterline, which made them vulnerable to flooding and restricted their use to calm seas.
Turrets were weapon mounts designed to protect the crew and mechanism of the artillery piece and with the capability of being aimed and fired in many directions as a rotating weapon platform. This platform can be mounted on a fortified building or structure such as an anti-naval land battery, or on a combat vehicle, a naval ship, or a military aircraft.
Origins
Designs for a rotating gun turret date back to the late 18th century. Practical rotating turret warships were independently developed in Great Britain and the United States with the availability of steam power in the mid-19th century.
British developments
thumb|left| was one of the first ocean-going turret ships.
During the Crimean War, Captain Cowper Phipps Coles of the British Royal Navy constructed a raft with guns protected by a 'cupola' and used the raft, named Lady Nancy, to shell the Russian town of Taganrog in the Black Sea. Lady Nancy "proved a great success", and Coles patented his rotating turret after the war. Following Coles' patenting, the British Admiralty ordered a prototype of Coles' design in 1859, which was installed in the floating battery vessel, , for trials in 1861, becoming the first vessel to be fitted with a revolving gun turret. Coles' design aim was to create a ship with the greatest possible all round arc of fire, as low in the water as possible to minimise the target.
The British Admiralty accepted the principle of the gun turret as a useful innovation, and incorporated it into other new designs. Coles submitted a design for a ship having ten domed turrets each housing two large guns. The design was rejected as impractical, although the Admiralty remained interested in turret ships and instructed its own designers to create better designs.
Coles enlisted the support of Prince Albert, who wrote to the First Lord of the Admiralty, the Duke of Somerset, supporting the construction of a turret ship. In January 1862, the Admiralty agreed to construct a ship, , which had four turrets and a low freeboard, intended only for coastal defence. Coles was allowed to design the turrets, but the ship was the responsibility of the Chief Constructor Isaac Watts. Ericsson designed USS Monitor in 1861. Erickson's most prominent design feature was a large cylindrical gun turret mounted amidships above the low-freeboard upper hull, also called the "raft". The raft extended well past the sides of the lower, more traditionally shaped lower hull. A small armoured pilot house was fitted on the upper deck towards the bow, however, its position prevented Monitor from firing her guns straight forward. One of Ericsson's prime goals in designing the ship was to present the smallest possible target to enemy gunfire.
The turret's rounded shape helped to deflect cannon shot. A pair of donkey engines rotated the turret through a set of gears; a full rotation was made in 22.5 seconds during testing on 9 February 1862. When not in use, the turret rested on a brass ring on the deck that was intended to form a watertight seal. In service, however, this proved to leak heavily, despite caulking by the crew. Direct hits at the turret with heavy shot also had the potential to bend the spindle, which could also jam the turret.
The turret was intended to mount a pair of smoothbore Dahlgren guns, but they were not ready in time and guns were substituted. They could fire a round shot or shell up to a range of at an elevation of +15°.
Culmination
thumb| incorporated hydraulic mechanisms into the turret, and marked the transition toward the modern [[battleship.]]
of 1871 and of 1872 represented the culmination of this pioneering work. These ironclad turret ships were designed by Edward James Reed. They were also the world's first mastless battleships, built with a central superstructure layout, and became the prototype for all subsequent warships, leading directly to the modern battleship.
Surviving examples
- The only preserved steam and sail turret ship in Europe is the mid 19th century Dutch ironclad HNLMS Schorpioen.
- The Chilean and Peruvian flagship Huascar is a memorial at Talcahuano.
- A replica of the Chinese battleship Dingyuan was built as a museum ship in 2003.
See also
- Barbette ship