Gaff
A spar to support the head of a gaff sail.

Gaff Rig
Four-sided mainsail defined by two booms, one located on the bottom, perpendicular to the mast, and another, located on top, at an angle from the mast.

Galley
The kitchen area of a boat.

Gangway
The area of a ship's side where people board and disembark.

Gear
A general term for ropes, blocks, tackle and other equipment.

Give-Way Vessel
A term used to describe the vessel which must yield in meeting, crossing, or overtaking situations.

Grab Rails
Hand-hold fittings mounted on cabin tops and sides for personal safety when moving around the boat.

Ground Tackle
A collective term for the anchor and its associated gear.

Gunwale
The upper edge of a boat's sides.

Halyard
Line which pulls up the sail.

Harbor
A safe anchorage, protected from most storms; may be natural or manmade, with breakwaters and jetties; a place for docking and loading.

Hard Chine
An abrupt intersection between the hull side and the hull bottom of a boat so constructed.

Hatch
An opening in a boat's deck fitted with a watertight cover.

Head
A marine toilet. Also the upper corner of a triangular sail.

Heading
The direction in which a vessel's bow points at any given time.

Headway
The forward motion of a boat. Opposite of sternway.

Helm
The wheel or tiller controlling the rudder.

Helmsperson
The person who steers the boat.

Hitch
A knot used to secure a rope to another object or to another rope, or to form a loop or a noose in a rope.

Hold
A compartment below deck in a large vessel, used solely for carrying cargo.

Hull
The main body of a vessel.

Hypolimnion
The layer of water in a thermally stratified lake that lies below the thermocline, is non-circulating, and remains perpetually cold.

Hypothermia
A life threatening condition in which the body's temperature is subnormal and the entire body cools.