A
Abaft: Toward the rear (stern) of the boat. Behind.
Abeam: At right angles to the keel of the boat, but not on the boat.
Aboard: On or within the boat.
Above Deck: On the deck (not over it: see ALOFT)
Abreast: Side by side; by the side of.
Adrift: Loose, not on moorings or towline.
Aft: Toward the stern of the boat.
Aground: Touching or fast to the bottom.
Ahead: In a forward direction.
Alee: Away from the direction of the wind. Opposite of windward.
Aloft: Above the deck of the boat.
Amidships: In or toward the center of the boat.
Anchorage: A place suitable for anchoring in relation to the wind, seas and bottom.
Astern: In back of the boat, opposite of ahead.
Athwartships: At right angles to the centerline of the boat; rowboat seats are generally athwart ships. Aweigh: The position of anchor as it is raised clear of the bottom.

B
Backstay: A wire support for the mast, usually running from the stern to the head of the mast.
Bale: A fitting on the end of a spar, such as the boom, to which a line may be led.
Ballast Weight: usually metal, placed low in a boat to provide stability.
Barber Hauler: A line attached to the jib or jib sheet, used to adjust the angle of sheeting by pulling the sheet toward the centerline of the boat.
Battens: Flexible strips of plastic, fiber glass or Carbon fiber, most commonly used in the mainsail and non-overlapping jibs to support the aft portion, or roach, so that it will not curl.
Beat: (beating) To sail in the direction from which the wind is blowing by making a series of tacks.
Batten Down: Secure hatches and loose objects for approaching bad weather.
Beam: The maximum width of the boat.
Beam Reach: A point of sail where the boat is sailing at a right angle to the wind (wind coming from abeam).
Bearing: The direction of an object expressed either as a true bearing as shown on the chart, or as a bearing relative to the heading of the boat.
Bight: The part of the rope or line, between the end and the standing part, on which a knot is formed.
Bilge: A rounding of the hull along the length of the boat where the bottom meets the side.
Bilge Boards: Similar to centerboards, and used to prevent lee way.
Bilge boards: are on either side of the centerline at the bilges.
Binnacle: A support for the compass, raising it to a convenient position.
Bitter End: The last part of a rope or chain. The inboard end of the anchor rode.
Board boat: A small boat, usually mono rig. May have a shallow cockpit well. Typically has almost no freeboard.
Boat Hook: A short shaft with a fitting at one end shaped to facilitate use in putting a line over a piling, recovering an object dropped overboard, or in pushing or fending off.
Bobstay: Wire Stay underneath the bowsprit; helps to counteract the upward pull exerted by the forestay.
Boom Crutch: Support for the boom, holding it up and out of the way when the boat is anchored or moored. Unlike a gallows frame, a crutch is stowed when boat is sailing.
Boom: free swinging spar attached to the foot of the sail with forward end pivoting on the mast.
Boom Vang: A system used to hold the boom down, particularly when boat is sailing downwind, so that the mainsail area facing the wind is kept to a maximum. Frequently extends from the boom to a location near the base of the mast. Usually tackle- or lever-operated.
Boomkin: (bumpkin) Short spar extending aft from the transom. Used to anchor the backstay or the sheets from the mizzen on a yawl or ketch.
Boot Top: A painted stripe that indicates the waterline.
Bow: The forward part of a boat.
Bowline: Knot used to form a temporary loop in a line.
Bow Line: A docking line leading from the bow.
Bowsprit: A short spar extending forward from the bow. Normally used to anchor the forestay.
Brale: Partially furling sails to lessen wind resistance or partially unfurling sails to make them ready for instant use. On a square sail this is accomplished with leech and clew lines. See “Scandalize”.
Bridge: The location from which a vessel is steered and its speed controlled. “Control Station” is really a more appropriate term for small craft.
Bridge Deck: The transverse partition between the cockpit and the cabin.
Bridle: A short length of wire with a line attached at the midpoint. A bridle is used to distribute the load of the attached line. Often used as boom travelers and for spinnaker down hauls.
Brightwork: Varnished woodwork and/or polished metal.
Bulkhead: An interior partition commonly used to stiffen the hull. May be watertight.
Bullseye: A round eye through which a line is led, usually in order to change the direction of pull.
Bulwark: A vertical extension above deck level designed to keep water out of and sailors in the boat.
Bunk: Sleeping Berth.
Buoy: An anchored float used for marking a position on the water or a hazard or a shoal and for mooring.
Burdened Vessel: That vessel which, according to the applicable Navigation Rules, must give way to the privileged vessel. The term has been superseded by the term “give-way”.

C
Cabin: A compartment for passengers or crew.
Cap: A piece of trim, usually wood, used to cover and often decorate a portion of the boat, i.e., caprail.
Capsize: To turn over.
Capstan: drum like part of the windlass used for winding in rope, cables, or chain connected to cargo or anchors.
Cast Off: To let go.
Catamaran: A twin-hulled boat, with hulls side by side.
Centerboard: A board lowered through a slot in the centerline of he hull to reduce sideways skidding or leeway. Unlike a daggerboard, which lifts vertically, a centerboard pivots around a pin, usually located in the forward top corner, and swings up and aft.
Chafing Gear: Tubing or cloth wrapping used to protect a line from chafing on a rough surface.
Chain plate: The fitting used to attach stays to the hull.
Charley Noble: Galley stove pipe.
Chart: A map for use by navigators.
Chine: A line, running along the side of the boat, where the bottom forms an angle to the side. Not found on round-bottom boats.
Chock: A fitting through which anchor or mooring lines are led. Usually U-shaped to reduce chafe.
Cleat: A fitting to which lines are made fast. The classic cleat to which lines are belayed is approximately anvil-shaped.
Clew: For a triangular sail, the aftmost corner.
Clove Hitch: A knot for temporarily fastening a line to a spar or piling.
Coach Roof: Also trunk. The cabin roof, raised above the deck to provide headroom in the cabin.
Coaming: A vertical extension above the deck to prevent water from entering the cockpit. May be broadened to provide a base for winches.
Cockpit: An opening in the deck from which the boat is handled.
Code Zero (sail): a Cross over between a Genoa and spinnaker. Typically used to go upwind in very light air and to reach as the wind refreshes. Made of very light laminate fibers is the “must have” sail for fast racing sailboats and multihulls where the apparent wind angle never goes beyond 135 degrees.
Coil: To lay a line down in circular turns.
Companionway: The main entrance to the cabin, usually including the steps down into the cabin.
Counter: At the stern of the boat, that portion of the hull emerging from below the water, and extending to the transom. Apr to be long in older designs, and short in more recent boats.
Course: The direction in which a boat is steered.
Coxswain: Sailor in charge of and steering a small boat.
Crosstrees: Horizontal members attached to the mast acting as spreaders for the shrouds.
Cuddy: A small shelter cabin in a boat.
Cunningham: A mainsail control device, using a line to pull down the mainsail a short distance from the luff to the tack. Flattens the sail.
Current: The horizontal movement of water.

D
Daggerboard: A board dropped vertically through the hull to prevent leeway. May be completely removed for beaching or for sailing downwind.
Danger Zone: The area encompassed from dead ahead of your boat to just abaft your starboard beam. You must stand clear of any boat in the “danger zone”.
Davits: cranes used to raise or lower small boats and light items from deck to water level.
Dead Ahead: Directly ahead.
Dead Astern: Directly aft.
Dead-Eyes: Blocks in the shroud rigging used to adjust tension.
Deadlight: Either a cover clamped over a porthole to protect it in heavy weather or a fixed light set into the deck or cabin roof to provide light below.
Deck: A permanent covering over a compartment, hull or any part thereof.
Dinghy: A small open boat. A dinghy is often used as a tender for a larger craft.
Displacement: The weight of water displaced by a floating vessel, thus, a boat’s weight.
Displacement Hull: A type of hull that plows through the water, displacing a weight of water equal to its own weight, even when more power is added.
Ditty Bag: Small bag used for carrying and stowing small personal items or kits.
Dock: A protected water area in which vessels are moored. The term is often used to denote a pier or a wharf.
Dolphin: A group of piles driven close together and bound with wire cables into a single structure.
Dodger: A screen, usually fabric, erected to protect the cockpit from spray and wind.
Downhaul: A line used to pull a spar, such as the spinnaker pole, or a sail, particularly the mainsail, down.
Draft: The depth of water a boat draws.
Dry Sailing: When boats, especially smaller racers, are kept on shore instead of being left anchored or moored, they are dry sailed. The practice prevents marine growth on the hull and the absorption of moisture into it.

E
Earrings: Small lines, by which the uppermost corners of the largest sails are secured to the yardarms.
Ease: To loosen. To let out the line of a sail.
Ebb: A receding current.
Embayed: The condition where a sailing vessel (especially one which sails poorly to windward) is confined between two capes or headlands by a wind blowing directly onshore.
EPIRB: Emergency Position Indication Radio Beacon. Radio signaling aid that allows the transmission of emergency position calls.
Even keel: When a boat is floats evenly to its waterline, well balanced.
Eye: Loop, often in the end of a line; as in: The sewn in eye in the dock line is very handy.
Eye splice: (knots) Braiding the end of a line into itself to form a loop.

F
Fairlead: A fitting used to alter the direction of a working line, such as a bullseye, turning block, or anchor chock.
Fathom: Six feet.
Fender: A cushion, placed between boats, or between a boat and a pier, to prevent damage.
Fid: Tool used by riggers in splicing line.
Figure Eight Knot: A knot in the form of a figure eight, placed in the end of a line to prevent the line from passing through a grommet or a block.
Flare: The outward curve of a vessel’s sides near the bow. Or A distress signal.
Flood: A incoming current.
Fluke: The palm of an anchor.
Fo’c’sle An abbreviation of forecastle. Refers to that portion of the cabin which is farthest forward. In square-riggers often used as quarters for the crew.
Following Sea: An overtaking sea that comes from astern.
Foot: For a triangular sail, the bottom edge.
Fore And Aft: In a line parallel to the keel.
Foremast: vertical spar most forward.
Forepeak: The compartment farthest forward in the bow of the boat. Often used for anchor or sail stowage. In larger ships the crews quarters.
Foresail: lowest square sail on the foremast.
Forestay: Wire, sometimes rod, support for the mast, running from the bowsprit or foredeck to a point at or near the top of the mast.
Foretriangle The triangle formed by the forestay, mast, and fore deck.
Forward: Toward the bow of the boat.
Fouled: Any piece of equipment that is jammed or entangled, or dirtied. When racing, a boat victim of another’s boat rule breakage.
Fractional Rig: A design in which the forestay does not go to the very top of the mast, but instead to a point 3/4~ 7/8’s, etc., of the way up the mast.
Frames: Ribs that form the shape of the hull.
Freeboard: The distance between the deck and the waterline. Most often it will vary along the length of the boat.

G
Gaff: a free swinging spar attached to the top edge of a sail.
Galley: The kitchen area of a boat.
Gangway: The area of a ship’s side where people board and disembark.
Garboard: Used in conjunction with strake. Refers to the planks, or strakes, on either side of and adjacent to the keel.
Give-Way Vessel: A term used to describe the vessel which must yield in meeting, crossing, or overtaking situations.
Give Way Together: Command used by Coxswain in larger rowing boats.
Gollywobbler: A full, quadrilateral sail used in light air on schooners. It is flown high, between the fore and main mast, and is also known as a fisherman’s staysail.
Gooseneck: The fitting that connects the boom to the mast.
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.
Gunter Rig: Similar to a gaff rig, except that the spar forming the “gaff” is hoisted to an almost vertical position, extending well above the mast.
Gunwale: Most generally, the upper edge of the side of a boat.
Guy: A line used to control the end of a spar. A spinnaker pole, for example, has one end attached to the mast, while the free end is moved back and forth with a guy.

H
Halyards: Lines used to hoist or lower sails or flags. Lines used to haul up the sail and the wooden spars (boom and gaff) that hold the sails in place.
Hard Chine: An abrupt intersection between the hull side and the hull bottom of a boat so constructed.
Hatch: an opening in the deck for entering below.
Head: For a triangular sail, the top corner. Also a marine toilet.
Headfoil: a grooved rod fitted over the forestay to provide support for luff of the sail or help support the forestay.
Head Knocker: A block with a jam cleat, located on the boom and used to control the main sheet on small boats.
Heading: The direction in which a vessel’s bow points at any given time.
Headsails: Any sail forward of the foremast.
Headway: Forward motion of boat opposite to sternway.
Helm: The wheel or tiller controlling the rudder.
Helmsman: Sailor who steers the boat.
Hiking Stick: (tiller extension) An extension of the tiller that enables the helms man to sit at a distance from it.
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 vessel, used solely for carrying cargo.
Hull: The main body of a vessel.

I
In Irons: A sailboat with its bow pointed directly into the wind, preventing the sails from filling properly and stopping the boat.
In the Offing: In the water visible from on board a ship, now used to mean something imminent.
Inboard: More toward the center of a vessel; inside; an engine fitted inside a boat.
Inspection Port: A watertight covering, usually small, that may be removed so the interior of the hull can be inspected or water removed.
Iron Topsail: An auxillary motor on a schooner.
Iron wind: What sailors call inboard engines

J
Jacklines: or jack stays. Lines, often steel wire with a plastic jacket, from the bow to the stern on both port and starboard. The Jack Lines are used to clip on the safety harness to secure the crew to the vessel while giving them the freedom to walk on the deck.
Jacobs Ladder: A rope ladder, lowered from the deck, as when pilots or passengers come aboard.
Jam Cleat: A cleat designed to hold a line in place without slipping. -It consists of two narrowing jaws with teeth in which the line is placed.
Jetty: A structure, usually masonry, projecting out from the shore; a jetty may protect a harbor entrance.
Jettison: To throw overboard.
Jib: A triangular foresail in front of the foremast.
Jib Halyard: The line that raises and lowers the jib.
Jib Sheet: A line that controls the jib; as in: Trim the jib sheet according to the telltales.
Jibe: To turn the stern of the boat through the eye of the wind; as in: To jibe under control we first trim the mainsheet.
Jibboom: A spar used to extend the bowsprit.
Jiffy reefing: A fast method of reefing. Lines pull down the luff and the leech of the sail, reducing its area.
Joggle: A slender triangular recess cut into the faying surface of a frame or steamed timber to fit over the land of clinker planking, or cut into the faying edge of a plank or rebate to avoid feather ends on a strake of planking. The feather end is cut off to produce a nib. The joggle and nib in this case is made wide enough to allow a caulking iron to enter the seam.
Jumper Stay: A short stay supporting the top forward portion of the mast. The stay runs from the top of the mast forward over a short jumper strut, then down to the mast, usually at the level of the spreaders.
Jumbo: The larger of the headsails.

K
Kedge Off: Using an anchor to pull the boat into deeper water; as in: If we run aground we might be able to kedge off.
Keel: The timber at the very bottom of the hull to which frames are attached.
Keelson: A structural member above and parallel to the keel.
Ketch: A type of boat with two masts the second of which is lower and is stepped forward of the rudder post; as in: The ketch design provides a wide variety of possible sail combinations.
Kick-up: Describes a rudder or centerboard that rotates back and up when an obstacle is encountered. Useful when a boat is to be beached.
Knockabout: A type of schooner without a bowsprit.
Knockdown: When the heel of the boat approaches 90°; as in: Most sailors will never experience a knockdown.
Knot: 1. A measure of speed equal to one nautical mile (6076 feet) per hour. 2. A fastening made by interweaving rope to form a stopper, to enclose or bind an object, to form a loop or a noose, to tie a small rope to an object, or to tie the ends of two small ropes together.

L
Lapper: A foresail which extends back of and overlapping the mast, such as a 110% genoa jib.
Latitude: The distance north or south of the equator measured and expressed in degrees.
Lazarette: A storage space in a boat’s stern area.
Lazy Jack: Light lines from the topping lift to the boom, forming a cradle into which the mainsail may be lowered.
Lead: Refers to the direction in which a line goes. A boom vang, for example, may “lead to the cockpit.”
Leech: The aft edge of a triangular sail.
Leech Line: A line running through the leech of the sail, used to tighten it.
Lee: The side sheltered from the wind.
Leeward: The direction away from the wind. Opposite of Windward.
Leeway: The sideways movement of the boat caused by either wind or current.
Lee Boards: Pivoting boards on either side of a boat which serve the same function as a centerboard. The board to leeward is dropped, the board to windward is kept up.
Lie Ahull: A storm tactic whereby no sail is set; as in: We tried to lie ahull but found the motion not to our liking.
Lift: Opposite of header, a wind shift allowing the helmsperson to steer closer to the desired course; as in: If we get a lift we may not need to tack.
Lines: Rope or cordage used for various purposes aboard a boat.
Log: A record of courses or operation. Also, a device to measure speed.
Long Stay: A description for the relative slackness of an anchor chain; this term means taught and extended.
Longitude: Position measured in degrees east or west of the meridian at Greenwich, England.
Loose-Footed: Describes a mainsail attached to the boom at the tack and clew, but not along the length of it’s foot.
Lubber Line: A mark or permanent line on a compass indicating the direction forward parallel to the keel when properly installed.
Luff: The forward edge of a triangular sail. In a mainsail the luff is that portion that is closest to the mast.
Luff or Luffing: when the vessel is brought too far into the wind the trailing edge or Leech of the sail begins to shiver or shake.

M
Mainmast: the tallest mast of the ship; on a schooner, the mast furthest aft.
Mainsail: The lowest square sail on the mainmast.
Marline: A light twine size line which has been tarred.
Marline Selling: A tool for opening the strands of a rope while splicing.
Mast: Main vertical spar used to support sails and their running rigging and in turn is supported by standing rigging.
Mast Step: Fitting or construction into which the base of the mast is placed.
Masthead Rig: A design in which the forestay runs to the peak of the mast.
Mechanical advantage (or purchase): A mechanical method of increasing an applied force. Disregarding the effects of friction, if a force of 100 pounds applied to a tackle is magnified to a force of 400 pounds, the purchase or mechanical advantage is said to be four to one, or 4: 1.
Midship: Approximately in the location equally distant from the bow and stern.
Mizzen: A fore and aft sail flown on the mizzenmast.
Monkey Deck: A false deck built over a permanent deck. Often used in the bow of larger sailing ships, forward of the anchor windlass and provides a working platform around the portion of the bowsprit as it attaches to the ship.
Mooring: An arrangement for securing a boat to a mooring buoy or a pier.

N
Nautical Mile: One minute of latitude; approximately 6076 feet: about 1/8 longer than the statute mile of 5280 feet.
Navigation: The art and science of conducting a boat safely from one point to another.
Navigation Regulations (or COLREGS): The regulations governing the movement of vessels in relation to each other, generally called steering and sailing rules.
Neap-Tide: tide period in which high water is lowest (soon after the moons 1st and 3rd quarter).

O
Oar: Device used to propel small boats by rowing.
Off the Wind: Sailing with the wind coming from the stern or quarter of the boat.
Offshore Wind: A wind blowing off the land, opposite of…
On the Hard: Description of a boat that has been hauled and is now sitting on dry land.
On the Wind: Sailing close hauled. Sailing toward the wind as much as possible with the wind coming from the bow.
Onshore Wind: A wind blowing onto the land
Outboard: Toward or beyond the boat’s sides. A detachable engine mounted on a boat’s stern.
Outhaul: 1. Usually a line or tackle, an outhaul is used to pull the clew of the mainsail towards the end of the boom, thus tightening the foot of the sail. 2. Straightening out misaligned or partially fouled sails and rigging.
Outrigger: A structure which extends outboard to suspend lines or nets over the water or small secondary hull.
Overboard: Over the side or out of the boat.
Overhang: When the bow and or stern extend beyond the waterline; as in: Many older boats have a lot of overhang.
Overpowered: Too much power in the sails producing excessive heel and difficult steering; as in: When the wind speeds up we depower the sails to prevent being overpowered.
Overtake: To come up from behind; as in: When we overtake another vessel we must keep out of her way.

P
Pay Out: to feed line over the side of the boat, hand over hand.
Pedestal: A vertical post in the cockpit used to elevate the steering wheel into a convenient position.
Pier: 1. A loading platform extending at an angle from the shore. 2. A wood, metal or concrete pole driven into the bottom. Craft may be made fast to a pile; it may be used to support a pier (see PILING) or a float.
Piling: Support, protection for wharves, piers etc.; constructed of piles (see PILE).
Pilothouse: a small cabin on the deck of the ship that protects the steering wheel and the crewman steering.
Planking: wood boards that cover the frames outside the hull.
Piloting: Navigation by use of visible references, the depth of the water, etc.
Planing: A boat is said to be planing when it is essentially moving over the top of the water rather than through the water.
Planing Hull: A type of hull shaped to glide easily across the water at high speed.
Port: The left side of a boat looking forward. A harbor.
Privileged Vessel: A vessel which, according to the applicable Navigation Rule, has right-of-way (this term has been superseded by the term “stand-on”).
Pulpit: A metal framework on deck at the bow or stern. Provides a safety railing and serves as an attachment for the lifelines.
Pushpit: pulpit located on the stern.

Q
Quarter: The sides of a boat aft of amidships.
Quartering: Sailing with the wind between the stern and the beam
Quartering Sea: Sea coming on a boat’s quarter.
Queen topsail: small stay sail located between the foremast and mainmast.

R
Rake: The fore or aft angle of the mast. Can be deliberately induced (by adjustment of the standing rigging) to flatten sails, balance steering, etc. Normally slightly aft.
Reef points: A horizontal line of light lines on a sail which may be tied to the boom, reducing the area of the sail during heavy winds.
Rigging: the lines that hold up the masts and move the sails (standing and running rigging).
Roach: The curved portion of a sail extending past a straight line drawn between two corners. In a mainsail, the roach extends past the line of the leech between the head and the clew and is often supported by battens.
Rocker: The upward curvature of the keel towards the bow and stern.
Rode: The anchor line and/or chain.
Rope: In general, cordage as it is purchased at the store. When it comes aboard a vessel and is put to use it becomes line.
Roller furler: Furling unit. Reduces the area of a sail by rolling it around a stay, the mast, or the boom. Most common on headsails.
Rub-rail: Also rubbing strake or rub strake. An applied or thickened member at the rail, running the length of the boat; serves to protect the hull when alongside a pier or another boat.
Rudder: A vertical plate or board for steering a boat.
Run: To allow a line to feed freely.
Running Backstay: Also runner, or preventive backstay. A stay that supports the mast from aft, usually from the quarter rather than the stern. When the boat is sailing downwind, the runner on the leeward side of the mainsail must be released so as not to interfere with the sail.
Running Rigging: The adjustable portion of the rigging, used to control sails and equipment.
Running Lights: Lights required to be shown on boats underway between sundown and sunup.

S
Sail: a piece of cloth that catches or directs the wind and so powers a vessel.
Sailing Rig: the equipment used to sail a boat, including sails, booms and gaffs, lines and blocks.
Scandalize: On a gaff rig the sail is made loose footed, the clew is brought forward along the boom and the sail cloth is drawn up in folds along the gaff and mast. From this position the sail is instantly available for use.
Schooner: Sailing ships with at least 2 masts (foremast and mainmast) with the mainmast being the taller. Word derives from the term “schoon/scoon” meaning to move smoothly and quickly. ( a 3-masted vessel is called a “tern”).
Scope: Technically, the ratio of length of anchor rode in use to the vertical distance from the bow of the vessel to the bottom of the water. Usually six to seven to one for calm weather and more scope in storm conditions.
Screw: A boat’s propeller.
Scupper: Drain in cockpit, coaming, or toe-rail allowing water to drain out and overboard. When in toe rail, properly known as “freeing port”.
Scuttle: A round window in the side or deck of a boat that may be opened to admit light and air, and closed tightly when required.
Seat Locker: A storage locker located under a cockpit seat.
Sea Cock: A through hull valve, a shut off on a plumbing or drain pipe between the vessel’s interior and the sea.
Seat locker: A storage locker located under a cockpit seat.
Self-bailing cockpit: A watertight cockpit with scuppers, drains, or bailers that remove water.
Self-tacking: Normally applied to a sail that requires no adjustment other than sheeting when boat is tacked.
Seamanship: All the arts and skills of boat handling, ranging from maintenance and repairs to piloting, sail handling, marlinespike work, and rigging.
Sea Room: A safe distance from the shore or other hazards.
Seaworthy: A boat or a boat’s gear able to meet the usual sea conditions.
Secure: To make fast.
Set: Direction toward which the current is flowing.
Sheer: The line of the upper deck when viewed from the side. Normal sheer curves up towards the bow and stern. Reverse sheer curves down towards the bow and stern. Compound sheer, curving up at the front of the boat and down at the stern, and straight sheer are uncommon.
Sheer Strake: The topmost planking in the sides, often thicker than other planking.
Sheets: Lines used to control the position of a sail.
Shrouds: Lateral supports for the mast, usually of wire or metal rod.
Ship: A larger vessel usually thought of as being used for ocean travel. A vessel able to carry a “boat” on board.
Shroud: a line or wire running from the top of the mast to the spreaders, then attaching to the side of the vessel.
Skeg: usually refers to a structural support to which the rudder is fastened.
Slab Reefing: Also points reefing, and sometimes jiffy reefing. Reduces the area of the mainsail by partially lowering the sail and re-securing the new foot by tying it to the boom with points, or light lines attached to the sail.
Slack: Not fastened; loose. Also, to loosen.
Sounding: A measurement of the depth of water.
Spar: a pole or a beam.
Spar Poles: most often of wood, aluminum or carbon fiber, used as supports, such as the mast, boom, or spinnaker pole.
Spinnaker: A large, triangular sail, most often symmetrical, flown from the mast in front of all other sails and the forestay. Used sailing downwind.
Spirit: The spar that supports the peak of a spritsail.
Splashboard: A raised portion of the hull forward of the cockpit intended to prevent water entering.
Spreaders: Also crosstrees. Short horizontal struts extending from the mast to the sides of the boat, changing the upward angle of the shrouds.
Spring Line: A pivot line used in docking, undocking, or to prevent the boat from moving forward or astern while made fast to a dock.
Spritsail: A four-sided fore and aft sail set on the mast, and supported by a spar from the mast diagonally to the peak of the sail.
Standing Rigging: Permanent rigging used to support the spars. May be adjusted during racing, in some classes.
Stay: a line or wire from the mast to the bow or stern of a ship, for support of the mast (fore, back, running, and triadic stays).
Staysail: A sail that is set on a stay, and not on a yard or a mast.
Stem: the timber at the very front of the bow.
Strake: On wooden boats, a line of planking running from the bow to the stern along the hull.
Squall: A sudden, violent wind often accompanied by rain.
Square Knot: A knot used to join two lines of similar size. Also called a reef knot.
Standing Part: That part of a line which is made fast. The main part of a line as distinguished from the bight and the end.
Stand-On Vessel: That vessel which has right-of-way during a meeting, crossing, or overtaking situation.
Starboard: The right side of a boat when looking forward.
Stem: The most forward vertical structural member in the bow.
Stern: The after part of the boat.
Stern Line: A docking line leading from the stern.
Stow: To put an item in its proper place.
Strake: On wooden boats, a line of planking running from the bow to the stern along the hull.
Swamp: To fill with water, but not settle to the bottom.
Sweat And Tail: Sweat is the act of hauling a halyard to raise a sail or spar done by pulling all slack outward and then downward. Tail is controlling, coiling, and securing the running end of the halyard.

T
Tabernacle: A hinged mast step located on deck. Since it is hinged, the mast may be lowered easily.
Tack: On a triangular sail, the bottom forward corner. Also, to turn the bow of the boat through the wind so the wind exerts pressure on the opposite side of the sail.
Taffrail: The rail at the stern of the boat.
Tang: A fitting, often of sheet metal, used to attach standing rigging to a spar, or to the hull.
Thwart: A transverse structural member in the cockpit. In small boats, often used as a seat.
Thwartships: At right angles to the centerline of the boat.
Tide: The periodic rise and fall of water level in the oceans.
Tiller: A bar or handle for turning a boat’s rudder or an outboard motor.
Toe-rail: A low rail, often slotted, along the side of the boat. Slots allow drainage and the attachment of blocks.
Topmast: a second spar carried at the top of the fore or main mast, used to fly more sail.
Topping Lift: A line or wire rope used to support the boom when a boat is anchored or moored.
Topsides: The sides of a vessel between the waterline and the deck; sometimes referring to onto or above the deck.
Trampoline: The fabric support that serves for seating between the hulls of a catamaran.
Transom: The flat, or sometimes curved terminating structure of the hull at the stern of a boat.
Trapeze: Wire gear enabling a crewmember to place all of his weight outboard of the hull, thus helping to keep the boat level.
Traveler: A fitting across the boat to which sheets are led. In many boats the traveler may be adjusted from side to side so that the angle of the sheets can be changed to suit conditions.
Trim: Fore and aft balance of a boat.
Twing / Tweaker: Similar to a Barberhauler, a twing adjusts the angle of sheeting.

U
Under Bare Poles: To have no sails up.
Underway: Vessel in motion, not moored or aground
Uphaul: A line or wire used to control the height of a spinnaker pole
Upwind: Any course closer to the wind than a beam reach

V
V Bottom: A hull with the bottom section in the shape of a “V”.
V-Hull: The shape of a boat or ship in which the contours of the hull come in a straight line to the keel.
Van: A device, usually with mechanical advantage, used to pull the boom down, flattening the sail.
Vang: A line used to stabilize the boom.
Vanishing Angle: The maximum degree of heel after which a vessel becomes unable to return to an upright position.
Veer: To change directions suddenly. To change direction clockwise.
Ventilator: Construction designed to lead air below decks. May have a cowl, which can be angled into or away from the wind; and may be constructed with baffles, so that water is not allowed below, as in Dorade ventilator.
Vessel: Any kind of boat, ship or yacht.

W
Wake: Moving waves, track or path that a boat leaves behind it, when moving across the waters.
Warp: Heavier lines (rope or wire) used for mooring, anchoring and towing. May also be used to indicate moving (warping) a boat into position by pulling on a warp.
Waterline: A line painted on a hull which shows the point to which a boat sinks when it is properly trimmed (see BOOT TOP).
Way: Movement of a vessel through the water such as headway, sternway or leeway.
Wheel: device used for steering a boat.
Widow-maker: a term for the bowsprit (many sailors lost their lives falling off the bowsprit while tending sails).
Whisker Pole: A short spar, normally kept stowed, which may be used to push the clew of a jib away from the boat when the boat is running downwind.
Window: A transparent portion of a jib or mainsail.
Windward: Toward the direction from which the wind is coming.
Wishbone: A boom composed of two separate curved pieces, one on either side of the sail. With this rig, sails are usually self tending and loose-footed.

Y
Yacht: A pleasure vessel, a pleasure boat; in American usage the idea of size and luxury is conveyed, either sail or power.
Yankee: a fore-sail flying above and forward of the jib, usually seen on bowsprit vessels.
Yard: A rod or spar fastened across a mast to support a sail.
Yaw: To swing or steer off course, as when running with a quartering sea.
Yawl: Boat: smaller powered boat used to provide steerage-way when not under sail. Rig: two masts, aft one is smaller (shorter) and located astern of rudder post.

Z
Zephyr: 1. A gentle breeze. 2. The west wind.