Daggerboard: A type of light centerboard that is lifted vertically; often in pairs, with the leeward one lowered when beating.
Davy Jones' Locker: An idiom for the bottom of the sea.
Day-blink: Moment at dawn where, from some point on the mast, a lookout can see above low lying mist which envelops the ship.
Day beacon: An unlighted fixed structure which is equipped with a dayboard for daytime identification.
Dayboard: The daytime identifier of an aid to navigation presenting one of several standard shapes (square, triangle, rectangle) and colors (red, green, white, orange, yellow, or black).
Dead ahead: Exactly ahead, directly ahead, directly in front.
Deadeye: A wooden block with holes (but no pulleys) which is spliced to a shroud. It is used to adjust the tension in the standing rigging of large sailing vessels, by lacing through the holes with a lanyard to the deck. Performs the same job as a turnbuckle.
Deadrise: The design angle between the keel (q.v.) and horizontal.
Dead run: See running.
Deadwood: A wooden part of the centerline structure of a boat, usually between the sternpost and amidships.
Decks: The top of the boat; the surface is removed to accommodate the seating area. The structures forming the approximately horizontal surfaces in the ship's general structure. Unlike flats, they are a structural part of the ship.
Deck hand, decky: A person whose job involves aiding the deck supervisor in (un)mooring, anchoring, maintenance, and general evolutions on deck.
Deck supervisor: The person in charge of all evolutions and maintenance on deck; sometimes split into two groups: forward deck supervisor, aft deck supervisor.
Deckhead: The under-side of the deck above. Sometimes paneled over to hide the pipe work. This paneling, like that lining the bottom and sides of the holds, is the ceiling.
Derrick: A lifting device composed of one mast or pole and a boom or jib which is hinged freely at the bottom.
Devil seam: The devil was possibly a slang term for the garboard seam, hence "between the devil and the deep blue sea" being an allusion to keel hauling, but a more popular version seems to be the seam between the waterway and the stanchions which would be difficult to get at, requiring a cranked caulking iron, and a restricted swing of the caulking mallet.
Devil to pay (or devil to pay, and no pitch hot): "Paying" the devil is sealing the devil seam. It is a difficult and unpleasant job (with no resources) because of the shape of the seam (up against the stanchions) or if the devil refers to the garboard seam, it must be done with the ship slipped or careened.
Dhow: the generic name of a number of traditional sailing vessels with one or more masts with lateen sails used in the Red Sea and Indian Ocean region, typically weighing 300 to 500 tons, with a long, thin hull. They are trading vessels primarily used to carry heavy items, like fruit, fresh water or merchandise. Crews vary from about thirty to around twelve, depending on the size of the vessel.
Dinghy:
1. A type of small boat, often carried or towed as a ship’s boat by a larger vessel.
2. Also a small racing yacht or recreational open sailing boat, often used for beginner training rather than sailing full-sized yachts.
3. Utility dinghies are usually rowboats or have an outboard motor, but some are rigged for sailing.
Directional light: A light illuminating a sector or very narrow angle and intended to mark a direction to be followed.
Displacement: The weight of water displaced by the immersed volume of a ship's hull, exactly equivalent to the weight of the whole ship.
Displacement hull: A hull designed to travel through the water, rather than planing over it.
Disrate: To reduce in rank or rating; demote.
Dodger: A hood forward of a hatch or cockpit to protect the crew from wind and spray. Can be soft or hard.
Doghouse: A slang term (in the US, mostly) for a raised portion of a ship's deck. A doghouse is usually added to improve headroom below or to shelter a hatch.
Dogvane: A small weather vane, sometimes improvised with a scrap of cloth, yarn or other light material mounted within sight of the helmsman. (See Tell-Tale)
Dog watch: A short watch period, generally half the usual time (e.g. a two hour watch rather than a four hour one). Such watches might be included in order to rotate the system over different days for fairness, or to allow both watches to eat their meals at approximately normal times.
The Doldrums or equatorial calms: The equatorial trough, with special reference to the light and variable nature of the winds.[7]
Dolphin: A structure consisting of a number of piles driven into the seabed or riverbed as a marker.
Dory or doree, dori or (RN) dorey: A shallow-draft, lightweight boat, about 5 to 7 metres long, with high sides, a flat bottom and sharp bows. Traditionally used as fishing boats, both in coastal waters and in the open sea.
Double-shotted: The practice of loading smooth-bore cannons with two cannon-balls.
Downbound:
1. Adjective describing a vessel traveling downstream.
2. Adjective describing eastward-traveling vessels in the Great Lakes region (terminology as used by the St. Lawrence Seaway Development Corporation).
Downhaul: A line used to control either a mobile spar, or the shape of a sail. A downhaul can also be used to retrieve a sail back on deck.
Drabbler: An extra strip of canvas secured below a bonnet (q.v.), further to increase the area of a course
Draft or draught (both /?dr??ft/): The depth of a ship's keel below the waterline.
Dragon boat (also dragonboat) is one of a family of traditional paddled long boats of various designs and sizes found throughout Asia, Africa and the Pacific Islands. For competitive events, they are generally rigged with decorative Chinese dragon heads and tails. Dragon boat races are traditionally held during the annual summer solstice festival.
Dressing down
1. Treating old sails with oil or wax to renew them.
2. A verbal reprimand.
Driver: The large sail flown from the mizzen gaff.
Driver-mast: The fifth mast of a six-masted barquentine or gaff schooner. It is preceded by the jigger mast and followed by the spanker mast. The sixth mast of the only seven-masted vessel, the gaff schooner Thomas W. Lawson, was normally called the pusher-mast.
Drogue (/?dro??/): a device to slow a boat down in a storm so that it does not speed excessively down the slope of a wave and crash into the next one. It is generally constructed of heavy flexible material in the shape of a cone. Also see sea anchor.
Dunnage (/?d?n?d?/):
1. Loose packing material used to protect a ship's cargo from damage during transport. (Also see Fardage)
2. Personal baggage.
