forecastle

Forecastle, also forecastle, is the forward part of a ship's upper deck or the forward section of its superstructure. On traditional sailing vessels it is the portion of the main deck forward of the foremast, often raised as a forecastle deck above the waterline. The term derives from fore + castle, alluding to a forward, fortress-like area of the ship.

Historically, the forecastle housed the crew's living quarters and stores, and it contained equipment for handling the anchor, such as the windlass and chain lockers. It could also serve as a workspace for deck crews and, on warships, a place for mounting light weapons. The forecastle head is the upper interior portion of the bow area, and the term fo'c'sle is the common nautical contraction of forecastle.

In modern ships the forecastle generally denotes the forward portion of the ship's superstructure or deck. It may include the crew's accommodation, the forward mess, and various storage spaces. The traditional forecastle is more prominent on old sailing ships, while some contemporary vessels use the term mainly for historical or architectural reference.

The phrase on the forecastle is used in nautical speech to describe conditions at the bow, typically exposed and weather-weary areas during heavy seas.