Island mooring generally constructed of wooden piles or cement blocks.
Donkeyengine
Ship's auxiliary engine.
Donkeyman
Engineroom petty officer whose duties include being responsible for the maintenance of the ship's auxiliary engines.
Door
Section of a ship which is used to provide a means of entry for vehicles into a rollon rolloff vessel. Sometimes the door and the access ramp are combined while in other cases, the two are separate. In most cases, the door provides a watertight barrier against the entry of sea water.
Door gusset
Strengthening on the two top corners of some shipping containers, such as some insulated and refrigerated containers. It is achieved by having the top and side frames meet at an angle across the corner, rather than being squared off. Because of this, there is a loss of clearance at the top corners when loading the container.
Door to door
Said of a service or freight rate provided by a container shipping line whereby goods are loaded into a shipping container at the shipper's premises and not unloaded until they arrive at the consignee's premises. Also referred to as house to house.
D.o.p.
Dropping outward pilot (q.v.).
Double purchase
Method of rigging a derrick using two double blocks, the lower one carrying the hook and having the rope or wire in four parts. The gain in power, known as purchase, is roughly equivalent to the number of parts of the rope, in this case, by a factor of four. The safe working load (s.w.l.) of the derrick should not be exceeded in spite of the gain in power.
Double sling
Attachment to a crane consisting of two lengths of chain joined at one end to a single ring. At the other end, each has a cargo hook. The chains are placed around the load and hooked on to the chain or ring.
Doublebottom (tank)
Space between the floor of a ship's holds and the bottom of the ship. Its purpose is to help prevent sea water entering the holds in the event of running aground. It is used for the carriage of fuel oil or fresh water or, if the ship is not carrying a cargo, for water ballast.
Doublerigged
Said of a hatchway which is served by two derricks.
Down by the head
Said of a ship whose draught forward is slightly deeper than her draught aft. This often makes the handling of a ship difficult at sea. Also referred to as trimmed by the head. When a ship's draught aft is slightly deeper than her draught forward, she is said to be down by the stern or trimmed by the stern.
Down to her marks
Said of a ship whose hull is immersed to the appropriate load line and which cannot therefore load any further cargo. Sea also Load line.
Downtime
Period during which equipment, such as a crane, cannot be used, often because it has a fault or is undergoing repairs or maintenance.
D.p.p.
Dirty petroleum products (q.v.)
Draft
Widely used alternative spelling of draught. For definition, see Draught (1) and Draught (2) below.
Draught (1)
Depth to which a ship is immersed in the water; this depth varies according to the design of the ship and will be greater or lesser depending not only on the weight of the ship and everything on board, such as cargo, ballast, fuel and spares, but also on the density of the water in which the ship is lying. A ship's draught is determined by reading her draught marks, a scale marked on the ship's stem and stern.
Draught (2)
Widely used to designate depth of water, for example the depth of water available at a port or place.
Draught limitation
Maximum depth of water to which the hull of a ship may be immersed at a certain port or place. Normally expressed in feet or metres, this figure is used in conjunction with the ship's deadweight scale to determine the quantity in tonnes of cargo, known as the lift, which the ship can carry.
Draught survey
Survey undertaken at the discharge port to determine the quantity of cargo on board a ship. The survey is in two parts: before and after discharge. Prior to discharge, the surveyor ascertains the draughts forward and aft and, taking into consideration the density of the water in which the ship is lying and any hogging or sagging calculates the ship's displacement tonnage. He then sounds the ship's tanks to determine the quantity of fuel, fresh water and ballast on board. After discharge he repeats the procedure and arrives at a new displacement tonnage. After making allowances for any fuel and fresh water used or taken on board during discharge as well as any ballast pumped aboard, he calculates the quantity of cargo. This is sometimes used as the basis on which payment is made for bulk cargoes.
Draw (to)
To have a draught of (a certain number of feet or metres). Fow example, it may be said that a particular ship draws four metres when immersed to her summer load line.
Drawback
Repaymant, when goods are reexported, of duty previously paid on imported goods.
