Lock gates usually consist of a pair of leaves turning upon vertical heelposts placed in the hollow-quoin recesses of the side walls, meeting at an angle in the centre of the opening, and shutting, at the same time, against the pointing sill at the bottom. This type of gates offers many advantages as well as some inconveniences, among which are the thrust on the side walls, difficulty in ensuring the complete closing of the leaves and water-tightness along the meeting posts and the sill against which the gates abut.
V. Cherre