[2] The Mercury 18 is a recreational keelboat, originally built predominantly of plywood and, starting in 1952, from fiberglass with wood trim.

The single chined hull has a spooned raked stem, a raised counter transom, a keel-hung rudder controlled by a tiller and a fixed long keel.

[1] For sailing the design is equipped with two jumper stays, the topmost or which is angled forward, plus a backstay.

[2] The design is supported by an active US west coast type club, the Mercury Class, that organizes racing.

[7] In a 1994 review Richard Sherwood wrote, "this classic-design, full-keel sloop is usually found in the [United States] Northeast or on the West Coast.