Constructed in 1903 across the entrance passage into the North Dock (nprn 34207).
(Field notes by D.J.Roberts, RCAHMW, 08 December 1977).
The pair of steel gates were operated with hydraulic power from the North Dock Engine House (nprn 34208).
B.A.Malaws, RCAHMW, 17 June 2010.