The PS Lincoln Castle was the last of the River Humber ferries to be built prior to the construction of the road bridge, which brought the service to a close. One of three sister ships, amazingly all of which have survived, the Lincoln Castle was built in 1940 at the A. & J. Inglis boatyard on the River Clyde in Scotland. Owned by the London and North Eastern Railway Company (LNER) she was 200ft (60.6m) in length, 33ft (10m) across the beam, had a gross tonnage of 598 tonnes, and was powered by a triple expansion diagonal reciprocating steam engine.

Completed after the outbreak of the Second World War, the PS Lincoln Castle's journey to Grimsby was never going to be an easy one. There were only two routes that could be taken. To the south, around the south-west coast of England and up through the English Channel, thereby risking attack by both the German navy and air forces, or to the north around Scotland and into the stormy waters of the North Sea. Deciding on the northern route, the Lincoln Castle soon encountered a severe storm in which she was damaged, forcing her to return to the River Clyde yard for repair. A second attempt was made in the spring of 1941, this time as part of a larger convoy. Although spotted by a German dive-bomber, PS Lincoln Castle arrived safely in Grimsby to begin a busy life transporting troops and supplies along the River Humber to whereever they were needed.