Maritime Glossary
Source-cited definitions for shipping, engineering, navigation, and regulatory terminology. Confidence-scored and verified against primary IMO, IHO, and industry sources.
- Deadweight TonnageDWT · deadweight
- Deadweight tonnage (DWT) is the total weight a ship can safely carry, in tonnes, the difference between its loaded displacement and its empty lightship weight. It includes cargo plus fuel, water, stores, ballast and crew.
- vessel-measurementscommercialhigh confidence
- Demurrage
- Demurrage is money the charterer pays the shipowner when a ship is kept loading or discharging for longer than the agreed laytime. It compensates the owner for the vessel's lost earning time while it waits in port beyond the allowance.
- commercialcharteringlegalhigh confidence
- Dispatchdespatch
- Despatch, or dispatch money, is a sum the shipowner pays back to the charterer as a reward for completing loading or discharging in less than the allowed laytime. It is the opposite of demurrage, and is usually set at half the demurrage rate.
- commercialcharteringhigh confidence
- Displacementdisplacement tonnage · ship displacement
- Displacement is the actual weight of a ship, equal to the weight of the water it pushes aside, or displaces, when floating. It is the true weight of the vessel and everything aboard at a given moment, measured in tonnes.
- naval-architecturestabilityhigh confidence
- Double Bottomdouble-bottom tanks · inner bottom
- The double bottom is the space between a ship's outer bottom shell and an inner watertight bottom, or tank top. It provides a second skin protecting against flooding after a grounding, and its tanks hold ballast, fuel or fresh water.
- ship-structuretanksstabilityhigh confidence
- Draftdraught
- Draft (or draught) is the vertical distance from the waterline down to the lowest point of a ship's hull, usually the bottom of the keel. It tells you how deep the ship sits and therefore the minimum water depth it needs to float safely.
- vessel-measurementsnavigationseamanshiphigh confidence
- Dry Dockdrydock · graving dock
- A dry dock is a basin that can be flooded to admit a ship and then pumped dry, leaving the vessel supported on blocks with its whole hull exposed. Drydocking allows inspection, repair, painting and survey of the underwater hull and fittings.
- engineeringmaintenanceregulationhigh confidence
- Dunnagedunnage material
- Dunnage is the material (such as timber, boards, mats, bags or matting) placed among and around cargo to secure it, keep it off the deck and away from moisture, allow ventilation, and fill spaces so it cannot shift during the voyage.
- cargoseamanshipstowagehigh confidence