HMS Ark Royal (1914) - Design and Description

Design and Description

The Royal Navy had conducted trials in 1913 with a modified cruiser, Hermes, to evaluate the ability of seaplanes to work with the fleet. They were successful enough that the Admiralty allocated £81,000 in the 1914–1915 Naval Programme to purchase a merchant ship for a more thorough modification than had been possible with Hermes to better accommodate seaplanes. A tramp steamer was purchased in 1914 that had just begun construction at the Blyth Shipbuilding Company so it could be easily modified to suit its new role.

Extensive changes to the ship were made in converting her to a seaplane tender, with the superstructure, funnel, and propulsion machinery moved aft and a working deck occupying the forward half of the ship. The deck was not intended as a flying-off deck, but for starting and running up of seaplane engines and for recovering damaged aircraft from the sea. The ship was equipped with a large aircraft hold, 150 feet (45.7 m) long, 45 feet (13.7 m) wide and 15 feet (4.6 m) high along with extensive workshops. Two 3-long-ton (3.0 t) steam cranes on the sides of the forecastle lifted the aircraft through the sliding hatch of the hangar onto the flight deck or into the water. She carried 4,000 imperial gallons (18,000 l; 4,800 US gal) of petrol for her aircraft in standard commercial 2-imperial-gallon (9.1 l; 2.4 US gal) tins.

She could carry five floatplanes and two to four regular, wheeled aircraft. The latter would have to return to land after launch, but the seaplanes would take off and land in the water alongside the carrier, lifted on and off the ship by the cranes. Her original complement of aircraft consisted of a Short Folder, two Wight Pushers, three Sopwith Type 807 seaplanes and two to four Sopwith Tabloid wheeled aircraft.

Ark Royal had an overall length of 366 feet (111.6 m), a beam of 50 feet 10 inches (15.5 m), and a draught of 18 feet 9 inches (5.7 m). She normally displaced 7,080 long tons (7,190 t), with a displacement of 7,450 long tons (7,570 t) at deep load. The ship had one vertical triple-expansion steam engine driving one propeller shaft. The ship's three cylindrical boilers generated enough steam to produce 3,000 indicated horsepower (2,200 kW) from the engine. The ship had a designed speed of 11 knots (20 km/h; 13 mph), but she made a speed of 10.64 knots (19.71 km/h; 12.24 mph) during her sea trials with 2,675 shaft horsepower (1,995 kW) in December 1914. Ark Royal carried 500 tonnes (490 long tons) of fuel oil, enough to give her a range of 3,030 nautical miles (5,610 km; 3,490 mi) at 10 knots (19 km/h; 12 mph).

The ship was armed with four QF 12-pounder 12 cwt guns and two machine guns. Including 60 aviation personnel, her crew totalled 180 officers and men. "Her truly unique feature was the steadying sail on the mizzen to help keep her head to the wind; she remains the only aircraft carrier to have been fitted with a sail."

Ark Royal was laid down on 7 November 1913 by the Blyth Shipbuilding Company in Blyth, Northumberland, as a freighter, probably intended for the coal-for-grain trade in the Black Sea. She was purchased in May 1914 and was launched on 5 September 1914. The ship was commissioned on 10 December 1914.