Chine (boating) - Reasons For Chines

Reasons For Chines

The oldest type of engineered boats are dugout canoes, which were built by hollowing out a log. These designs generally had rounded bottoms, which made best use of the round shape of the logs. Traditional planked hulls in most cultures are built by placing wooden planks oriented parallel to the waterflow and attached to bent wooden frames. This also produced a rounded hull, generally with a sharp bottom edge to form the keel. Planked boats were built in this manner for most of history.

The first hulls to start incorporating hard chines were probably shallow draft cargo carrying vessels used on rivers and in canals. The barge and later the scow used a flat bottom and near vertical sides, which provided the maximum cargo carrying capacity (in both space and displacement) available for a given depth of water.

Once sufficiently powerful marine motors had been developed to allow powerboats to plane, it was found that the flat underside of a chined boat provided maximum hydrodynamic lift, while the sharp discontinuity at the chine enabled spray to be deflected away as opposed to riding up the sides of the boat. Consequently, almost all boats designed for high speed on the plane are nowadays of hard chine construction.