Planing (boat)

Many forms of marine transport make use of planing, including fast ferries, racing boats, seaplanes, and water skis.

The earliest documented planing sailboat was a proa built in 1898 by Commodore Ralph Munroe.

A simple model of this effect is a solid slab of material that is heavier than water (like a steel plate) but is shaped and oriented to have a positive angle of attack.

(Exceptions to this include surfboards and other recreational planing hulls, which utilize rocker throughout for enhanced maneuverability when banking through turns.)

In contrast, in a displacement, or non-planing hull, the bottom is curved in side view (the curvature is called "rocker") all the way from bow to stern, in order to minimize wave drag.

In front view, the sections in the aft area may be straight, as in a racing hydroplane, to maximize planing forces and speed, but for practical reasons of stability and comfortable ride are often V-shaped, especially in boats intended for offshore use.

They utilize the push of the waveform more or less in combination with gravity and specific angles of attack for the hydrofoil to maximise propulsive force and reduce the net downforce and thus achieve planing lift.