A hinged, bronze or steel plate serving to protect the glass portlight in heavy weather.

1. A portion of a ship side or bottom where the plating has no curvature. 2. The midship portion of constant cross section, (the parallel middle body).

The condition under which the main propulsion plant, boilers and auxiliaries are not in operation due to the absence of power.

The lowest speed at which a ship can still be manoeuvred.

1. A portlight that does not open. 2. A hinged, bronze or steel plate serving to protect the glass portlight in heavy weather.

The rise or upward slant of the bottom of a ship from the keel to the bilge.

The deadweight is the difference between the displacement and the mass of empty vessel (lightweight) at any given draught. It is a measure of ship’s ability to carry various items: cargo, stores, ballast water, provisions and crew, etc.

A drawing used for estimating the additional draught or for determining the extra load that could be taken on board when a vessel is being loaded in water of density less than that of salt water.

The flat, vertical portion of the aft end of a ship.

A deaerator is a device that removes oxygen and other dissolved gases from liquids and pumpable compounds.

A representation of how many grams of CO2 a single ship can emit to move one ton of goods one nautical mile over a time horizon.

Decarbonization refers to the reduction or elimination of carbon dioxide from energy sources.

The decay chain refers to a series of radioactive decays of different radioactive decay products as a sequential series of transformations.

The decay energy is the energy released by a radioactive decay.

Decay heat is the heat released as a result of radioactive decay. This heat is produced as an effect of radiation on materials: the energy of the alpha, beta or gamma radiation is converted into the thermal movement of atoms.

A sound level unit which is one-tenth of a bel. It is used to compare levels of sound.

decision-making is regarded as the cognitive process resulting in the selection of a belief or a course of action among several possible alternative options, it could be either rational or irrational.

A platform in a ship corresponding to a floor in a building. See also car decks. - Bulkhead deck – The bulkhead deck is the highest deck to which the watertightbulkheads extend and are made effective.

Athwartship element of a vessel structure, which supports deck plating and which acts as a strut or tie connecting the vessel sides.

A unit consisting of two chambers (entry lock and main lock) installed on a support ship. This chamber allows for gas saturation, lodging, recovery and desaturation periods for divers performing a mission in a diving bell.