A Treatise On The Principles And Practice Of Dock Engineering

524 DOCK ENGINEERING. The ram or the connecting-rod, as the case may be, is usually attached to the gate through the medium of a girder or radius arm, one end of which is fixed to the heel-post and the other to a point somewhere about one-third of the length of the leaf from the mitre-post. In this way the pressure of the ram is more effectively applied to the gate, but the faut that the applica- tion of pressure is necessarily above the water line militates against any com- Fig. 520.—Arrangement of Gate Chains—Direct System. Fig. 521. —Overgate System. pletely satisfactory arrangement. The objection has possibly not so much weight in regard to iron and steel gates, which can be suitably stiffened, but is of so great importance to wooden gates as to have rendered the system practically inapplicable to such gates, owing to the difficulty of making them sufficiently rigid. In some cases attachment is made at a point more distant from the heel-post, and the stroke of the ram is correspondingly