|Glossary of nautical terms
This is a glossary of nautical terms; some remain current, many date from the 17th-19th century.
Daggerboard – A type of centerboard that is removed vertically.
Davy Jones’ Locker – An idiom for the bottom of the sea
Daybeacon – 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).
Deadeye – A round wooden plank which serves a similar purpose to
a block in the standing rigging of large sailing vessels.
Deadrise – The design angle between the keel (q.v.) and horizontal.
Decks – 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 – 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 curved seam in the hull planking closest to the
waterline when the ship is level. The seam between these two planks,
set at a nominal right angle to each other, is the devil seam. This
seam is particularly difficult to pay (and caulk) because there is
little support in the direction of the compression created during
caulking and expansion of the wood when wet. Hence, this seam "works" a
lot. A sailor sealing this seam must first cause the ship to list
(lean) toward the side opposite of the seam. This allows the sailor
access to the seam by hanging below it, "between the Devil and the deep
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 (closest to the
waterline) and because you are positioned below the natural waterline.
Directional light – A light illuminating a sector or very narrow angle and intended to mark a direction to be followed.
Disrate - To reduce in rank or rating; demote.
Dog watch – A short watch period, generally half the usual time
(eg a two hour watch between two four hour ones). Such a watch might be
included in order to slowly rotate the system over several days for
fairness, or to allow both watches to eat their meals at approximately
Dolphin – A structure consisting of a number of piles driven into
the seabed or riverbed in a circular pattern and drawn together with
Downhaul – A line used to control either a mobile spar, or the shape of a sail.
Draft – The depth of a ship's keel below the waterline.
Draught – See draft.
Dressing down – Treating old sails with oil or wax to renew them, or a verbal reprimand.
Driver – The large sail flown from the mizzen gaff.
Dunnage – Loose packing material used to protect a ship's cargo from damage during transport. Personal baggage.
Earrings – Small lines, by which the uppermost corners of the largest sails are secured to the yardarms.
Embayed – The condition where a sailing vessel is confined
between two capes or headlands, typically where the wind is blowing
Extremis – (also known as “in extremis”) the point
under International Rules of the Road (Navigation Rules) at which the
privileged (or stand-on) vessel on collision course with a burdened (or
give-way) vessel determines it must maneuver to avoid a collision.
Prior to extremis, the privileged vessel must maintain course and speed
and the burdened vessel must maneuver to avoid collision.