Grimsby Haven Lock, Lock Hill, Grimsby, North East Lincolnshire
The Grimsby Haven Lock and dock wall was built in 1798-9 by John Rennie, engineer, for the Grimsby Haven Company. This lock separated the tidal haven from the Humber estuary, creating the first dock at Grimsby. This was the Haven Dock, which opened in 1800 and was later incorporated in the Alexandra Dock. The bill for improving Grimsby Haven was passed in 1796. Work started in 1797 and in 1798 John Rennie was called in to rescue the scheme. A key element of Rennie's new design was this large lock which, as well as serving as the dock entrance, was designed to assist in scouring the harbour entrance and keep it clear of silt. To deal with the problem of building retaining walls in the soft ground here, Rennie devised a design using vaulted or "hollow" walls, which have a greater base area and are stronger than solid walls containing the same quantity of material. He subsequently used the method in other pier and harbour works (e.g. the Humber Dock at Hull, built 1803-9).
