- 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 - Small cranes used to raise or lower small boats and light items from deck to water level.
Dead Ahead - Directly ahead.
Dead Astern - Directly behind.
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 (window) set into the deck or cabin roof to provide light below.
Dead Reckoning - Also Ded Reckoning. Sometimes believed to be an abbreviation of Deduced Reckoning.
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.
Dismasted - Describes a boat with a mast broken while she was underway.
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.
Double Ender - A boat with a pointed stern. Typical of Norwegian designs.
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, made from Sunbrella fabric with plastic or glass windows, erected to protect the cockpit from spray and wind. These were custom fitted at the factory for each particular boat.
Downhaul - A line used to pull a spar, such as the spinnaker pole, or a sail, particularly headsail, down or toward the deck. In some cases a downhaul is used to tension the luff of the sail thereby changing the sail's shape in response to changing wind speed.
Dorade Box - A box attached to a ventilator, designed to allow air belowdecks while keeping water from getting inside the boat. Named after the first yacht to use this design of vent, the Olin Stephens designed ocean racer Dorade, built in 1929.
Draft - The depth of water a boat draws. As referring to a sail, it is the amount of curvature of the sail in a horizontal cross section. When you "move the draft" fore or aft, you are moving the peak of the curve in the horizontal plane either forward (to power up the sail) or aft (to de-power the sail).
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.
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Ease - To slack or let out a line.
Ebb - A receding current.
Electroless Nickel Plating - an alternative to traditional electro plating. Unlike electro nickel plating, Electroless Plating doesn’t depend on an electric current to apply nickel coating. Instead, a chemical reaction known as catalytic reduction deposits a layer of nickel-phosphorous alloy. Advantages over electroplating include:
• Uniform deposit thickness regardless of part geometry
• Reduced porosity (provides superior corrosion resistance)
• Improved hardness
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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. Also, a distress signal.
Flood - An 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.
Foreguy - A line that runs down the height of the spinnaker pole and is under positive control at all times.
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. See also: Headstay.
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, entangled, or dirtied.
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. (see: Shear)
Furling Drum - The device at the bottom of the furler where the Furling Line attaches to the drum. The Drum is equipped with a guard, basket, or cup that keeps the line in place and prevents multiple wraps of line from falling off of the Drum. It is the Drum that transfers the linear motion of the Furling Line into the rotational motion required to furl the the sail, i.e. when you pull on the line the Drum causes the Furling Gear to rotate. The Torque Tube, a tubular portion at the top of the drum, often covers the forestay turnbuckle hidden inside. It also holds the drum to the Luff Foil and causes the Luff Foil to rotate when the drum rotates. Note: There is no spring or other fancy gear inside of the Furling Drum. When you pull on the Furling Line, the line un-winds from the Drum causing it to rotate and wind up the sail. Un-wind the sail by pulling on the Sheets and the Furling Line agains rolls up on the Furling Drum.
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Gaff - A free swinging spar attached to the top edge of a sail.
Galley - The kitchen area of a boat.
Galling - A mode of failure for a threaded part, most commonly when made of stainless steel. When friction occurs between two threaded stainless steel parts that have not been lubricated, the resulting heat can cause the threads to become damaged and cause the parts to bind. Continued rotation will cause to parts to seize and finally shear off. Stainless steel threads must be lubricated to prevent this failure.
Galvanic Corrosion - The proceess by which one metal corrodes preferentially over another metal that is in contact with the first one. There must be electrical contact between the two metals for this process to occur. The process occurs between two dis-similar metals, or between two different alloys of the same base metal.
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.
Genoa - Properly, any jib sail that overlaps the mains'l when sheeted in. In practice, on Catalinas, the "Jib" is a 110% Genoa, but is referred to as a jib. A Genoa is anything larger. The Genoa JIb was introduced by Raimondo Panario at the 1926 Genoa Winter Regatta on his 6mR "Cora IV". Cora IV handily won the regatta thanks to the additional power of the oversized headsail.
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.
Gudgeon - A fitting on the back of a boat, mounted on the transom, used to connect the rudder to the hull. Most sailing dinghies have two gudgeons.
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.
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Halyard - Lines used to hoist or lower sails or flags.
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.
Headstay - The highest forestay. On Catalinas, which only have one forestay, the terms headstay and forestay are interchangeable.
Headway - Forward motion of boat opposite to sternway.
Helm - The mechanism steering the boat.
Helmsman - Sailor who is in control of the boat.
Hiking Stick - 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.
Hockle - A twisted knob of line that prevents the line from passing through a block or fairlead. In traditional three strand line a hockle forms when the line is twisted opposite the lay. The double braided construction of modern line resists forming hockles since they are equal twists of fiber in each direction. However, improper handling of braided line will also cause hockles. For example, coiling line around one's arm, or pulling new line from the end of a stationary spool rather than unrolling line from a rotating spool, forms one twist per wrap. On a long length of line these many twists cause a hockle to form when the line is put to use.
Hold - A compartment below deck in a vessel, used solely for carrying cargo.
Hull - The main body of a vessel.
Hull Speed - The theoretical top speed of a non-planing boat. It is calculated by multiplying 1.34 by the square root of the length of waterline (measured in feet). The result is given in knots (nautical miles per hour).
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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.
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