All the ships had a complement of 646 men and an overall length of 495 feet 8 inches (151.1 m), a beam of 69 feet 6 inches (21.2 m) and a draught of 24 ft 8 in (7.5 m). Propulsion was provided by two boilers connected to a steam turbine, which drove one shaft giving 8,500 shaft horsepower (6,300 kW). This arrangement could propel the ship at 18 knots (33 km/h; 21 mph).[3]
Tracker was laid down 3 November 1941, under a Maritime Commission (MARCOM) contract, MC hull 233, by Seattle-Tacoma Shipbuilding in Tacoma, Washington. She was originally intended to be the 2nd replacement merchant ship Mormacmail for Moore-McCormack Lines, Inc., however, before completion, the vessel was purchased by the US Navy. In 1942, she was given the designation BACV-6 and converted into an escort carrier at Willamette Iron & Steel, Portland, Oregon. She was launched on 7 March 1942, and commissioned 31 January 1943; she was transferred to the Royal Navy and renamed HMS Tracker.[3]
On 10 June 1944, while part of the antisubmarine screen of the Western Approaches Command for the D-Day landings, she collided with a River-classfrigate of the Royal Canadian Navy, HMCS Teme, causing damage to both ships. HMS Tracker continued operations despite stove-in bows until 12 June 1944. Thereafter, she was repaired and partially refitted in Liverpool, until 7 September 1944. On 8 December 1944, the ship sailed to the US to be used as an aircraft transport, and spent the remainder of the war ferrying aircraft and personnel in the Pacific.
In August 1945, she made a final trip to the UK, being returned to the US Navy in November 1945. She was sold in November 1946, and entered service as the merchant ship Corrientes, based in Argentina. She was scrapped in 1964.