The Liverpool class, designed by James Barnett, was derived from the 35ft 6in Self-righting motor-class lifeboat and had many similarities with it.

Like all early motor lifeboats, the Liverpool class carried an auxiliary sailing rig and had a drop keel just forward of the engine room.

The introduction of tractors to assist with carriage launching enabled the RNLI to consider a heavier, twin-engined version of the Liverpool class and a prototype was ordered but was destroyed in an air raid at the builder's yard at Cowes in May 1942.

Production got underway early in 1945 and the boat was powered by two 18 hp (13 kW) Weyburn AE4 four-cylinder petrol engines mounted in a watertight compartment.

The twin-engined variant was visually very similar but had 8 in (20 cm) more beam and the twin propellers were in protective tunnels.

Sold in 1963 to the Chilean Lifeboat Service, renamed Valparaiso II and stationed at Lirquén, Chile.