Glossary of maritime terms - D

DANGEROUS CARGO - see HAZARDOUS CARGO

DAVITS - Two radial cranes on a ship which hold the lifeboats, which are used to lower and lift lifeboats.

DEADWEIGHT (DWT) - A common measure of ship carrying capacity, equalling the number of tonnes of cargo, stores and bunkers that the ship can transport. It is the difference between the number of tonnes of water a vessel displaces 'light' and the number of tons it displaces when submerged to the 'deep load line'. A ship's cargo capacity is less than its total deadweight tonnage. The difference in weight between a vessel when it is fully loaded and when it is empty (in general transportation terms, the net) measured by the water it displaces. This is the most common, and useful, measurement for shipping as it measures cargo capacity and is usually used when referring to liquid and dry bulk ships.

DEAT - Department of Environmental Affairs and Tourism.

DECKHAND - Seaman who works on the deck of a ship and remains in the wheelhouse attending to the orders of the duty officers during navigation and manoeuvring.

DECK LOG - Also called Captain's Log. A full nautical record of a ship's voyage, written up at the end of each watch by the deck officer on watch. The principal entries are: courses steered; distance run; compass variations, sea and weather conditions; ship's position, principal headlands passed; names of lookouts, and any unusual position, principal headlands passed; names of lookouts, and any unusual happenings such as fire, collision, and the like.

DECK OFFICER - As distinguished from engineer officer, refers to all officers who assist the master in navigating the vessel when at sea, and supervise the handling of cargo when in port.

DECK HOUSE - Small superstructure on the top deck of a vessel, which contains the helm and other navigational instruments.

DEEP SEA TRADES - The traffic routes of both cargo and passenger vessels which are regularly engaged on the high seas or on long voyages.

DEEP STOWAGE - Any bulk, bagged or other type of cargo stowed in single hold ships.

DEMURRAGE - A fee levied by the shipping company upon the port or supplier for not loading or unloading the vessel by a specified date agreed upon by contract.

DERRICK - A type of crane found on merchant ships, the name is believed to have been the name of a London hangman named Derrick of the 17th century.

DISABLED SHIP - When a ship is unable to sail efficiently or in a seaworthy state as a result of engine trouble, lack of officers or crew, damage to the hull or ship's gear.

DOT - Department of Trade and Industry.

DOUBLE BOTTOM - General term for all watertight spaces contained between the outside bottom plating, the tank top and the margin plate. The double bottoms are sub-divided into a number of separate tanks which may contain boiler feed water, drinking water, fuel oil, ballast, etc. Now becoming common on all tankers.

DRAFT - The depth of a ship in the water. The vertical distance between the waterline and the keel, is expressed in metres except in the USA where it is in feet.

DRILL SHIP - Regular production ship usually on offshore oil wells, positioned by anchors or dynamic positioning. Possesses its own propulsion machinery.

DRY CARGO - Merchandise other than liquid carried in bulk.

DRY CARGO SHIP - Vessel that carries all merchandise, excluding liquid in bulk.

DRY DOCK - An enclosed basin into which a ship is taken for underwater cleaning and repairing. It is fitted with watertight entrance gates which when closed permit the dock to be pumped dry. Sometimes has two or more compartments separated by watertight doors. Dry docks are also referred to as Graving Docks.

DUNNAGE - A term applied to loose wood or other material used in a ship's hold for the protection of cargo.

DWT - Deadweight tonnes. |A|B|C|D|E|F|G|H|I|J|K|L|M|N|O|P|Q|R|S|T|U|V|W|X|Y|Z|