Back; towards the stern, as opposed to forward towards the bow.

Air vent in a hose with or without check valve; usually installed in half loop in a hose terminating below the waterline. Air vent prevents water from siphoning back into the vessel.

Valve with internal body ball shaped; used to control water flow on a thru-hull fitting.

Standing rigging (wire or rod) that supports bowsprit vertically to lower part of stem.

A mechanical or hydraulic system attached to the boom to control the sail shape by downward pull between forward part of boom and lower part of mast.

Fiberglass strips used to join bulkheads, floor timbers and hull liners to the hull of the vessel. Also may be referred to as fillet bonds or tabbing.

Forward end of the hull as opposed to the aft end, the stern.

Hairline cracks in fiberglass or plexiglass.

bearing Rubber bearing in bronze shell; supports propeller shaft in strut and/or stern tube (water cooled).

Separation of some or all layers in laminated fiberglass or plywood; often caused by impact or water penetration.

To make smooth by sanding and/or filling, following the contour of the vessel.

The curved section between the hull and the keel. In wooden boats, the name given to the planks in same area.

Device allowing items to swing to a level position when vessel heels. Stoves and kerosene lanterns are commonly gimbaled on sailing vessels.

Attachment fitting between boom and mast, usually a universal type joint. gunwale Uppermost part of hull sides (topsides) along deck level. Pronounced gun'l.

Opening used for paying out or storing anchor rode below.

Radiator normally using water instead of air for cooling. Used on fresh water cooled engines by circulating raw water with a separate pump through a heat exchanger that isolates the fresh water from the raw water. Heat exchangers may also be used for oil and transmission cooling.

Board or canvas installed inboard on bunk to prevent user from falling out of bunk in a seaway.

Small valve used to drain fluid; often installed on the bottom of a secondary fuel filter, in engine block or heat exchanger.

To use a sealant to prevent water intrusion to a seam or joint.

Line used for anchoring.

A drain or opening in the rail, gunwale or planking of a boat to permit accumulated water to flow overboard.

Quarter turn valve usually attached to a thru-hull fitting below the water to control water flow into and out of the vessel's plumbing.

Cover over forward part of sliding companionway hatch; makes companionway more water resistant.

Often used to describe non adhesion of two surfaces caused by an external applied force; like separation of fiberglass skin from balsa core.

The vessel's leading edge; the very forward vertical part of the bow. On wooden boats, the timber to which the forward portion of the planks are fastened on the bow. stern Aft end of hull, as opposed to forward end, the bow.

Appendage attached to bottom of hull to help support propeller shaft.

The portion that makes up the aft end of the hull, as opposed to the stem.

A track allowing sheets to slide across the vessels centerline. Mostly used for main sheet, provides more sail control than fixed sheet position.

An exhaust driven pump that forces additional air into the cylinders of the engine; normally used to increase horse power. On diesel engines, the turbo will also increase specific efficiency.

Line or device from boom to mast, cleat or rail. Often used as a preventer to avoid accidental jibes. Also see boom vang.

Air bubble built into laminate or gelcoat at time of construction. Size can vary from tiny bubbles to areas several feet in diameter. Small voids generally do not affect structural integrity.