The ''Ruler'' class of escort aircraft carriers served with the

Royal Navy during the Second World War The Royal Navy was an important component of the Allied forces during the Second World War and made a significant contribution to the victory over the Axis powers. Its main tasks included the protection of merchant ships in the Atlantic against ...

. All twenty-three ships were built by the

Seattle-Tacoma Shipbuilding Corporation The Seattle-Tacoma Shipbuilding Corporation (also operating as Todd Pacific) was an American corporation which built escort carriers, destroyers, cargo ships and auxiliaries for the United States Navy and United States Merchant Marine, merchant ...

in the United States as escort carriers, supplied under

Lend-Lease Lend-Lease, formally the Lend-Lease Act and introduced as An Act to Promote the Defense of the United States (),3,000 Hurricanes and >4,000 other aircraft) * 28 naval vessels: ** 1 Battleship. (HMS Royal Sovereign (05), HMS Royal Sovereign) * ...

to the United Kingdom. They were the most numerous single class of aircraft carriers in service with the Royal Navy. As built they were intended for three types of operations, "Assault" or

strike Strike may refer to: People *Strike (surname) * Hobart Huson, author of several drug related books Physical confrontation or removal *Strike (attack), attack with an inanimate object or a part of the human body intended to cause harm * Airstrike, ...

convoy A convoy is a group of vehicles, typically motor vehicles or ships, traveling together for mutual support and protection. Often, a convoy is organized with armed defensive support and can help maintain cohesion within a unit. It may also be used ...

escort, or

aircraft An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, i ...

ferry. After the Second World War some of the escort carriers were

scrapped Scrap consists of recyclable Recycling is the process of converting waste materials into new materials and objects. This concept often includes the recovery of energy from waste materials. The recyclability of a material depends on i ...

, while others had their

flight deck The flight deck of an aircraft carrier is the surface on which its aircraft take off and land, essentially a miniature airfield at sea. On smaller naval ships which do not have aviation as a primary mission, the landing area for helicopters ...

s removed and were converted to

merchant ship A merchant ship, merchant vessel, trading vessel, or merchantman is a watercraft that transports cargo or carries passengers for hire. This is in contrast to pleasure craft, which are used for personal recreation, and naval ships, which are ...

s (and all eventually scrapped by the 1970s).

Design and description

These ships were all larger and had greater aircraft capacity than all preceding American built escort carriers. They were laid down as escort carriers and were not converted

s. All the ships had a complement of 646 men and an

overall length The overall length (OAL) of an ammunition cartridge is a measurement from the base of the brass shell casing to the tip of the bullet, seated into the brass casing. Cartridge overall length, or "COL", is important to safe functioning of reloads i ...

of , a

beam Beam may refer to: Streams of particles or energy *Light beam, or beam of light, a directional projection of light energy **Laser beam *Radio beam *Particle beam, a stream of charged or neutral particles **Charged particle beam, a spatially lo ...

of and a draught of .Cocker (2008), p.82.

Propulsion Propulsion is the generation of force by any combination of pushing or pulling to modify the translational motion of an object, which is typically a rigid body (or an articulated rigid body) but may also concern a fluid. The term is derived from ...

was provided by one

shaft Shaft may refer to: Rotating machine elements * Shaft (mechanical engineering), a rotating machine element used to transmit power * Line shaft, a power transmission system * Drive shaft, a shaft for transferring torque * Axle, a shaft around whi ...

, two

boiler A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, centra ...

s and a

steam turbine A steam turbine or steam turbine engine is a machine or heat engine that extracts thermal energy from pressurized steam and uses it to do mechanical work utilising a rotating output shaft. Its modern manifestation was invented by Sir Charles Par ...

giving , which could propel the ship at .Cocker (2008), p. 79. Aircraft facilities were a small combined

bridge A bridge is a structure built to Span (engineering), span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, whi ...

–flight control on the

starboard Port and starboard are Glossary of nautical terms (M-Z), nautical terms for watercraft and spacecraft, referring respectively to the left and right sides of the vessel, when aboard and facing the Bow (watercraft), bow (front). Vessels with bil ...

side, two aircraft lifts, one

aircraft catapult An aircraft catapult is a device used to help fixed-wing aircraft gain enough airspeed and lift for takeoff from a limited distance, typically from the deck of a ship. They are usually used on aircraft carrier flight decks as a form of assist ...

and nine

arrestor wires An arresting gear, or arrestor gear, is a mechanical system used to rapidly decelerate an aircraft as it lands. Arresting gear on aircraft carriers is an essential component of naval aviation, and it is most commonly used on CATOBAR and STOBA ...

. Aircraft could be housed in the hangar below the flight deck. Armament comprised: two /50-calibre

dual purpose gun A dual-purpose gun is a naval artillery mounting designed to engage both surface and air targets. Description Second World War-era capital ships had four classes of artillery: the heavy main battery, intended to engage opposing battleships and ...

s in single mounts, sixteen Bofors

anti-aircraft gun Anti-aircraft warfare (AAW) is the counter to aerial warfare and includes "all measures designed to nullify or reduce the effectiveness of hostile air action".AAP-6 It encompasses surface-based, subsurface ( submarine-launched), and air-ba ...

s in twin mounts and twenty Oerlikon anti-aircraft cannon in single mounts. They had a maximum capacity for twenty-four

carrier-based aircraft A carrier-based aircraft (also known as carrier-capable aircraft, carrier-borne aircraft, carrier aircraft or aeronaval aircraft) is a naval aircraft designed for operations from aircraft carriers. Carrier-based aircraft must be able to launch i ...

which could be a mixture of

Grumman Martlet The Grumman F4F Wildcat is an American carrier-based fighter aircraft that entered service in 1940 with the United States Navy, and the British Royal Navy where it was initially known as the Martlet. First used by the British in the North Atla ...

, an American carrier-based

fighter aircraft Fighter aircraft (early on also ''pursuit aircraft'') are military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air supremacy, air superiority of the battlespace. Domina ...

, or

Vought F4U Corsair The Vought F4U Corsair is an American fighter aircraft that saw service primarily in World War II and the Korean War. Designed and initially manufactured by Vought, Chance Vought, the Corsair was soon in great demand; additional production con ...

, another type of American carrier-based fighter aircraft, or

Hawker Sea Hurricane The Hawker Hurricane was a British single-seat fighter aircraft designed and predominantly built by Hawker Aircraft. Some models were built in Canada by Canadian Car and Foundry. British variants Hurricane Mk I Hurricane Mk I (Early producti ...

fighter aircraft (a

navalised A navalised aircraft (or navalized aircraft) is an aircraft that has been specifically designed for naval use, in some cases as a variant of a land-based design. An aircraft based on an aircraft carrier is called carrier-based aircraft. Characte ...

Hawker Hurricane fighter aircraft), and

Fairey Swordfish The Fairey Swordfish is a retired biplane torpedo bomber, designed by the Fairey Aviation Company. Originating in the early 1930s, the Swordfish, nicknamed "Stringbag", was principally operated by the Fleet Air Arm of the Royal Navy. It was a ...

torpedo bomber A torpedo bomber is a military aircraft designed primarily to attack ships with aerial torpedoes. Torpedo bombers came into existence just before the World War I, First World War almost as soon as aircraft were built that were capable of carryin ...

, or

Grumman Avenger The Grumman TBF Avenger (designated TBM for aircraft manufactured by General Motors) is an American World War II-era torpedo bomber developed initially for the United States Navy and Marine Corps, and eventually used by several air and naval av ...

torpedo bomber /

anti-submarine An anti-submarine weapon (ASW) is any one of a number of devices that are intended to act against a submarine and its crew, to destroy (sink) the vessel or reduce its capability as a weapon of war. In its simplest sense, an anti-submarine weapon ...

aircraft.

Ships

First group

* * (crewed by the

Royal Canadian Navy The Royal Canadian Navy (RCN; , ''MRC'') is the Navy, naval force of Canada. The navy is one of three environmental commands within the Canadian Armed Forces. As of February 2024, the RCN operates 12 s, 12 s, 4 s, 4 s, 8 s, and several auxiliary ...

) * * * ^X * ^XX * * ^X

Second group

* * ^XX * ^X * ^X * ^XX * * ^X * ^X (crewed by the

) (torpedoed 22 August 1944, by ''U-354'' west of the North Cape) * ^X * ^X * * * ^XX * ^X * (torpedoed 15 January 1945, by ''U-1172'' in the Clyde estuary).Cocker (2008), p.83. :^X = Fitted for

warfare. :^XX = Fitted for strike-operations. :All the others were mainly used for aircraft transport with an added strike capability.

Notes

Bibliography

* {{WWII British ships Escort aircraft carrier classes