Monohull

A monohull has a single hull. To resist the force of the wind in the sails, which makes it heel (lean over), it relies on ballast placed low under the hull: the keel. The more the boat heels, the more that weight pulls it back upright, so a monohull rights itself after a capsize, unlike a multihull.

In offshore racing, the IMOCA, Class40 and Figaro classes are monohulls. The most recent add foils to lift the hull and go faster.