LYRA Sailing Sign Dictionary Explore 78 essential sailing terms with definitions and visual American Sign Language guidance from AIST and LYRA. Hull — The watertight body of a boat.Bow — The front end of a boat.Stern — The rear end of a boat.Starboard — The right side of a boat when looking toward the bow.Port — The left side of a boat when looking toward the bow.Keel — The fin-like structure below a boat that provides stability and resists leeway.Rudder blade — The steering blade at the stern of a boat.Mast — The vertical spar that supports the sails and rigging.Boom — The horizontal spar attached to the mast that supports the foot of the mainsail.Spreaders — Horizontal struts on a mast that hold the shrouds out.Bowsprit — A spar projecting from the bow to carry a headsail.Retract bowsprit — Bring a retractable bowsprit back into the boat.Forestay — A wire support running from the masthead to the bow.Shroud — A side wire support running from the mast to the side of the boat.Mainsail — The primary sail attached to the mast and boom.Jib — A forward sail attached to the forestay.Gennaker — A large asymmetric downwind headsail.Luff — The leading edge of a sail.Leech — The trailing edge of a sail.Foot — The lower edge of a sail between tack and clew.Leech line — A small line in the leech used to adjust its tension.Head — The upper corner of a sail.Tack — The forward lower corner of a sail.Clew — The aft lower corner of a sail where sheets attach.Batten pocket — A sleeve in a sail that holds a batten.Telltale — A small yarn or ribbon that indicates airflow over a sail.Leech line — A small line in the leech used to adjust its tension.Sheet — A line used to control a sail.Halyard — A line used to raise a sail.Downhaul — A line or tackle that pulls a sail or spar downward.Jib sheet — The sheet that controls the jib.Mainsheet — The sheet that controls the mainsail.Gennaker sheet — The line used to control a gennaker.Jib halyard — The halyard that raises the jib.Main halyard — The halyard that raises the mainsail.Gennaker halyard — The halyard that raises the gennaker.Boom vang — A tackle that pulls the boom down and controls leech tension.Cunningham — A downhaul used to tension the luff near the tack.Outhaul — The control that tensions the foot of a mainsail along the boom.Backstay — A wire support running from masthead to stern.Tie a knot — Form a knot in a line.Untie a knot — Release or undo a knot.Figure-eight stopper knot — A stopper knot that prevents a line running out of a block.Figure-eight on a bight — A figure-eight knot that creates a fixed loop.Square knot — A knot joining two ends of the same line.Slipped reef knot — A quick-release knot used to reef or temporarily shorten a sail.Bowline — A non-slip loop knot.Single block — A pulley block with one sheave.Vertical double block — A block with two sheaves arranged vertically.Horizontal double block — A block with two sheaves arranged side by side.Cam cleat — A spring-loaded cleat that grips a line between two cams.Clam cleat — A toothed cleat that holds a line in a slot.Horn cleat — A deck fitting around which a line is secured.Bitts (vessel) / bollard (dock) — Paired posts used to secure a line on a vessel or a dock.Carabiner — A metal clip with a spring gate.Shackle — A U-shaped connector closed with a pin.Fender — A protective cushion hung outside the hull.Buoy — A floating marker or warning device.Trim in — Pull a sail control line to increase tension.Ease slightly — Release a small amount of a sail control line.Ease fully — Release a sail control line completely.Tie — Form a knot in a line.Untie — Undo a knot in a line.Hoist — Raise a sail or other equipment.Head up — Turn the bow closer to the wind.Bear away — Turn the bow away from the wind.Tack / jibe — select maneuver — A wind-crossing maneuver: tack is bow-first and jibe is stern-first.Layline — An imagined line from which a boat can reach a mark without another tack.Helmsman — The crew member steering the boat.Sail trimmer — The crew member controlling sheets and sail shape.Bowman — The crew member working at the bow.Regatta — A series of sailboat races.In irons — A boat positioned directly into the wind and unable to sail forward.Close-hauled — Sailing as close to the wind as possible, roughly 30–45 degrees off it.Beam reach — Sailing with wind at 90 degrees to the boat's side.Broad reach — Sailing downwind at an oblique angle, between a reach and a run.Running / dead run — Sailing directly downwind, with the wind from astern.Wind — Air in natural motion near the earth's surface.