Glossary

Abaft:

Behind, as in a direction.

Abeam:

Towards or on the side of the boat.

Aft:

Towards the back (after) end or stern of the boat.

Aloft:

Up, usually into the rigging.

Athwartships:

In a direction 90-degrees from the centerline of the boat, that is towards the side of the boat.

Ballast:

Weight placed low in the boat or on the keel to lower the center of gravity and increase stability.

Barge:

A rectangular shaped vessel, usually having sloped panels on the bottom forward and aft.

Belay:

To tie off a line. Or to stop an action.

Belaying Pin:

Pin used for tying off a line. Usually arranged in a row in a pinrail around a mast or along a bulwark.

Beam:

The greatest width of the boat. Usually taken to the structure of the boat, not over the guardrails.

Bobstay:

Rigging support from the end of the bowsprit down to the stem, attaching close above the waterline.

Boom:

Spar on the bottom edge of the sail.

Boomkin:

Spar projecting aft from the stern that provides a base for a sheet.

Bootstripe:

Painted line on the boat above the waterline, separating the bottom paint from the topside paint. Usually has some sheer to it, at least the top edge of it.

Bow:

The front end of the boat.

Bowsprit:

Spar projecting forward from the bow, primarily to move the sails forward for sailing balance.

Brace:

Line controlling rotation of a yard.

Bulwark:

A solid panel, extending upwards from the deck, providing shelter and security for the people on deck. Often it is an extension of the hull sides, usually with tumblehome.

Cathead:

Shorter spars angled outward, near the bow, for attachment of whisker shrouds and/or lifting the anchor.

CB:

Center of Buoyancy. Geometric center of the immersed volume of the boat's hull.

CG:

Center of Gravity. Geometric center of the weights of the boat.

Chainplates:

Strong attachment points for the shrouds and runners.

Chine:

The angular joint, joining two hull panels, where the bottom and sides meet. That is, the ribs of the boat have an angular joint in them.

CL:

Centerline

Coaster:

A vessel that usually cruises along the coast. This can and does involve open water passages. Not intended to imply a lack of seagoing ability or capability.

Cutter:

Single masted sailboat with the mast set well aft and two or more headsails.

Displacement, cruising trim:

The weight of the boat with its usual load of people and supplies aboard. The boat displaces it's own weight in water - the volume of water displaced equals the boat's weight.

Displacement-length ratio:

Non-dimensional ratio indicating whether boat is "Ultralight" (under 150) and possibly driven quite fast, "light" (under 250) or "heavy" (over 350) and better suited to slower speeds. "Heavy" is likely to have more comfortable motion underway and at anchor, with its weight damping the motion.

Dolphin Striker:

Spar projecting downward from the bowsprit, to give a wider angle to the bobstay.

Double-ended:

A boat with no transom at the stern, but rather having the sides coming back together at the centerline.

Downhaul:

Line used to pull downward.

Draft:

Distance the deepest part of the boat is immersed in the water.

D/W:

Dishwasher

DWL:

Designed or datum water line.

English:

See Imperial.

Fantail:

An overhanging counter stern, usually elliptical in plan view.

Fin Keel:

Appendage below the hull, shaped like a short wing, to provide lateral resistance when sailing. Usually also the ballast keel.

Flare:

The outward slope of the hull sides, most often found at the bow.

Foc'sle:

A contraction of forecastle, the forward or bow cabin.

Fore and aft:

In the direction parallel to the centerline of the boat, towards where the boat is headed or where it has been.

Forward:

Towards the front end or bow of the boat.

Freeboard:

The distance from the water's surface to the deck (sometimes measured to the top of the hull or top of the bulwark.)

Fuel tankage:

Total capacity of the fuel tanks aboard.

Furling:

Gathering up or rolling up a sail for storage.

Gaff:

Spar at the top of a quadrilateral sail.

Galley:

The "kitchen" on the boat.

GM:

Distance from the center of gravity (G) to the Metacenter (M). The higher this number the greater the initial stability and ability to carry sail.

Guard Rails:

Outward structural projections to provide protection for the planking, usually heavily built.

Halyard:

Line used to raise and lower a sail.

Hanging Locker:

A closet for clothes.

Head:

The "bathroom" on the boat. Sometimes used to specifically note the water closet or toilet.

Headroom:

Clear vertical distance inside the boat for people to move about inside the boat without bumping their heads.

Headsails:

Sails set forward of the mast.

Headstay:

Forwardmost stay.

Imperial:

Measurements taken in units of feet, inches, pounds and gallons. Also known as the English system of measurement.

Keel:

The longitudinal member of the structure providing strength along the centerline of the vessel.

Ketch:

Two-masted vessel in which the after one is shorter, and located forward of the after end of the waterline and forward of the rudderpost.

Knockabout:

Sailing vessel with headsails set no further forward than the stemhead, not on a bowsprit.

Lateral Resistance:

Force from the shape of the boat and/or appendages to keep the boat from sliding to leeward under sail.

Lazyjacks:

Lines used to hold the sail in place as it is lowered so that it is held off the deck.

LCB:

Longitudinal Center of Buoyancy. Fore and aft position of geometric center of volume.

LCG:

Longitudinal Center of Gravity. The fore and aft location of the center of weights of the boat.

Leeward:

The downwind direction.

Length overall:

Total length of the structure. Does not usually include portions of the boat that hang beyond the main part of the structure, such as bowsprits.

Length designed waterline:

Total length of the boat measured where it meets the surface of the water.

Lift:

Line controlling vertical position of the yard.

Lkr.:

Abbreviation for locker.

LOA:

See Length Over All.

Metacenter:

(M) The point on the boat's vertical centerline about which it heels. The higher it is the more stable the boat. It moves up and down as the boat changes its angle of heel.

Metric:

Measurements taken in units of meters, kilograms and liters.

Off the wind:

Sailing with the wind coming from abaft the beam.

On the wind:

Sailing with the wind coming from forward.

Packet:

Traditionally, a vessel carrying freight, usually on a set route and schedule.

Particulars:

A table of measurements.

Peak:

The upper aft corner of a gaff sail.

Pilothouse:

The space aboard devoted to the controls for operating the boat.

Planking:

The outer skin of the boat. Also called plating on a metal boat.

Plating:

See Planking.

Port:

The left hand side of the boat when facing forward. Also, an opening in the side of the boat.

Portlight:

An opening port (window).

Prismatic coefficient:

The ratio of the area of a prism, with a section equal to the largest cross-section of the boat, to the total volume of the boat. The lower the number the more easily driven at lower speeds. A higher number, over 0.7, is usually associated with boats intended for higher speeds.

P/S:

Port and Starboard.

Rabbet:

The joint where the planking or plating joins the keel.

Raised Deck:

A style of design in which the deck is raised above the sheer line to create a more voluminous interior.

Ribs:

Transverse, or athwartships, structural framing members.

Round bilged:

The hull shape where the ribs are smoothly curved, with no breaks in them, from keel to sheer.

Rudder:

The movable blade, located directly aft of the propeller, that redirects the water flow and causes a reaction that steers the boat.

Rudder Post:

The part of the rudder that extends upwards for attachment of the tiller or steering gear.

Runners or Running Backstays:

Movable shrouds, set up to windward in heavier weather when tacking or on a reach. They would be in the way when off the wind.

Running Rigging:

Portions of the rigging that are adjustable.

Sail:

Cloth panel shaped to catch or redirect the wind.

Saloon:

Main living space aboard, like a living room ashore. Large ships sometimes also have dining saloons, where people congregate to be fed. Contrast with Salon, a place to have one's hair styled.

Schooner:

Vessel with two or more masts of either equal height or with the taller one aft.

Sheer:

The top edge of the hull at the side. Usually it's the widest part of the boat, unless it has tumblehome, and sweeps from bow to stern. Also, the sweeping curvature, when viewed from the side, of the top edge of the hull or some other portion of it.

Sheet:

Line used to control sail position.

Shelf-top Locker:

A locker that has a shelf on top of it. Sometimes there will be a port over the locker.

Shroud:

Supporting part of the standing rigging running athwartships.

Single Screw:

A single propeller on centerline of the boat.

Sloop:

Single masted rig with single headsail.

Spinnaker:

A headsail set flying, usually cut very full or rounded or lightweight cloth.

Spreader:

Athwartships spars on the sides of the mast to widen the angle of the shrouds.

Spud:

A vertically movable pole that drops through a tube built into the hull ("stick-in-the-mud") to hold the boat fixed in position, or to provide a point for a pivoting maneuver. Most useful in shallower waters or in areas with smaller tidal ranges.

Square Rig

:

Rig type that has horizontal spars crossing the mast to support the sails that are hung from them. The spars are adjustable from the horizontal by the lifts and in athwartships rotation by the braces.

Standing Rigging:

Rigging supports that are fixed in position.

Starboard:

The right hand side of the vessel when facing forward.

Stay:

Supporting part of the standing rigging running fore and aft.

Stem:

The leading edge of the hull, the extension of the keel that sweeps up and rises to join the deck.

Stern:

The back end of the boat.

Tankage:

The capacity of the tanks.

T/C:

Trash compactor.

Throat:

The upper forward corner of a gaff sail.

Tiller:

Handle attached to the rudder for steering control.

Topping Lift:

Line used to control height of end of boom.

Topsail:

Sail set above the gaff or the second sail up from the deck on a square-rigger.

Transom:

The panel at the stern, which joins the sides and bottom. It is often curved in plan view for strength and improved appearance.

Tumblehome:

Inward slope of the boat sides, narrowing as it goes up.

Twin Screw:

Two propellers (screws). The use of two usually well-spaced apart props gives good leverage when maneuvering in close quarters.

Wale:

The thicker layer of planking near the deck or a stripe painted to simulate it.

Waterline:

Floatation plane where the vessel sits in the water.

Waterplane:

The outline of the boat at the surface of the water.

Water tankage:

Total capacity of the water tanks aboard.

W/D:

Washer and Dryer.

Whisker Shrouds:

Rigging to support the bowsprit from moving in the horizontal plane.

Windward:

The upwind direction.

Yacht:

A vessel of pleasure or state. May be of any size.

Yard:

Horizontal spars for supporting the sails on a square rig.

Yardarm:

The end of the yard.

Yawl:

Two masted vessel with short mast aft, located aft of the after end of the waterline and/or the rudder post.