Lock Gates (Minic Ships 844)
Lock Gates (Minic Ships 844)(i)
Rather cleverly, the gates each have a hinge consisting of an arm terminating in a ring that can be threaded onto one of the many supporting "legs" of a Wharf or Pier, so with two parallel wharf or pier pieces, one has a wide choice of mounting/hinge points for the gates.
In the museum
The way that ours are displayed is less successful, as we have them between a wharf and the rubber "Dover Cliffs" shop-window display unit ... so while the "wharf-attached" gate is properly connected, the one by the rubber seafront doesn't have anything to mate with, so the hinge is visible.