A Dredger is a type of boat that is equipped with a tool called a dredge that draws sucks excavates or scrapes sediment such as sand silt gravel trash rocks debris and animal and plant matter from the ocean floor sea bed lakes or a waterway such as a river estuary or canal. The materials moved are then placed elsewhere or disposed of in an act known as dredging.

Noun: A Dredge is either a hydraulic or mechanical machine that removes the accumulation of silt (fine sand and clay) for the bottom of a river or harbor. This is both for safety reasons and to allow deeper vessels to use the waterway or harbor. Verb: The act of removing the accumulation of silt.

Drag is the term used when a ship is moving despite being anchored. The anchor is Dragging along the sea bed. This is something the crew member on anchor watch should be looking out for at all times.

The Draft is the depth of a loaded ship in the water. The measurement is taken from the level of the waterline to the lowest point of the hull.

A Dolphin or Mooring Dolphin is a collection of pilings clustered together to which a ship or boat ties their lines to to moor. They are also used to offer protection alongside a dock or the shore or in a waterway. Some Dolphins may be used as a base for navigational aids and some may also be used to stabilize a bridge or dock.

Dockage is a fee levied by a port authority for the length of water frontage used by a vessel that is moored at a wharf.

Verb: To Dock a ship - i.e. to bring a vessel into a port or harbor to moor it in its berth. Noun: The ship sailed into the Dock. A Dock is a structure that has been built so vessels can come ashore and load or unload cargo or passengers.

The Discharge Port is any port where a vessel unloads its cargo.

Disabled Ship: A ship is deemed disabled if it is found to not be seaworthy and safe or able to sail efficiently. This could be due to anything from not enough crew members or officers engine problems damage to the vessel’s gear or even to the vessel itself.

A Derrick is a type of crane found onboard merchant ships.

Demurrage is a fine payable to the owner of a vessel by a supplier or port for failing to load or unload the ship within the time agreed as per the contract.

A Deck Officer is an officer working in the deck department on a vessel - such as a Third Officer Second Officer or Chief Officer. They assist the Master in navigational duties and supervise cargo handling when in port.

A Deckhouse is a small superstructure (a part of the ship that is above its main deck) on a vessel’s top deck which contains the helm (a wheel or lever that controls the rudder) as well as other navigational instruments. 

A seafarer who works on the deck of a ship and in the wheelhouse. The Deckhand is an entry level job on a vessel and they will take orders from higher ranks particularly the duty officers during navigation and maneuvering.

Almost any vessel whether it’s a cruise ship an oil tanker a military vessel a general cargo ship a ferry or a heavy load carrier will count a Deck Cadet amongst her crew. A Deck Cadet is like an apprentice or a trainee seafarer. Typically a Cadet will help with daily operations and ship maintenance. Deck Cadet duties will also normally include assisting with preparations for departure and arrival at port. If a Cadet is working in Seafarer Jobs in the merchant navy this will include helping to supervise the loading and unloading of cargo as well as its storage onboard. On a cruise ship or ferry instead of cargo a Cadet will assist in ensuring that passenger onboarding is safely and efficiently carried out. They will also learn how to moor the vessel.

A Deck Barge carries oversize and/or heavy freight such as project cargo vehicles and machinery that is transported on its top deck as opposed to inside a hold. 

Deadweight tonnage (DWT) is a means of measuring how much weight a vessel can carry so that the maximum weight can be determined. DWT is the sum of the weight of the cargo crew fuel water (fresh and ballast) provisions and passengers (if there are any.)

Davits are two radial cranes on a ship which hold lower and lift the lifeboats.

Dredging is the act of removing sediment particularly silt (sand clay and mud) from river or harbor bottoms. This is done both so that deeper vessels can use the area and for safety reasons.

Drift can mean one of two things in a nautical sense: 1) for a vessel to float with the wind or current and 2) the distance a boat is carried by a current during a given time.

A Drillship (sometimes written Drill Ship) is a merchant vessel designed for scientific drilling purposes or for use in the exploratory offshore drilling of new gas and oil wells.

Dry Bulk Cargo is unpackaged cargo that is stored in loose piles for transportation. Such as grains nuts cement sand minerals and wheat.

Dry Cargo is cargo that is carried in bulk that is dry and not liquified.

More commonly called a Bulk Carrier or Bulker a Dry Cargo Ship is a vessel that carries bulk cargo that is dry and not liquified.

A Dry Dock is a narrow enclosed basin or vessel into which a ship can be floated for construction maintenance cleaning and repair. Dry Docks are fitted with watertight gates so that the dock can be pumped dry when the gates are closed.

Dunnage is any kind of packing material that is used as a protective filler inside a shipping container box or carton etc. to prevent movement and therefore damage to the cargo during shipping. Dunnage can be anything from wood to bubble wrap and from packing peanuts to inflatable air bags.

Duty is a government tax on imported merchandise.

DWT stands for Deadweight Tonnage (or Dead Weight Tonnage) - see below.