Fair

Favourable or clear when describing weather, and smooth or continuously shaped when describing a vessel’s surface or line.

A fair wind assists the intended passage or sailing direction, while fair weather generally means settled or suitable conditions in the stated context. Neither expression defines a wind force, visibility or sea-state threshold.

In boatbuilding, to fair a hull or component is to remove unintended hollows, bumps or abrupt changes so the designed surface or curve flows smoothly. Fairing can involve shaping, filling and sanding, but accuracy and structural limits matter more than achieving a merely glossy finish.