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Encyclopedia of Marine Technology


109 results


The acceptability of the conditions of a vessel in terms of vibration, noise, indoor climate and lighting as well as physical and spatial characteristics, according to prevailing research and standards for human efficiency and comfort.


An underwater structure installed on the ocean floor which is permanently or periodically manned. It is generally maintained at ambient pressure or at pressure of one atmosphere.


A halogenated hydrocarbon used in fire fighting which inhibits flame propagation. The use of halogenated hydrocarbons as fire-extinguishing media on new ships is prohibited.

HAM (Humid Air Motor) method

Humidification of combustion air used to reduce NOx emissions. In the HAM unit, relatively hot and dry air from the turbocharger is mixed with the water vapour from the heat exchanger.

Hampered vessel

A vessel restricted by its ability to manoeuvre by the nature of its work or its deep draft.


A short book containing information or instructions.

Handing over

Delivery of the ship to its owner.

Handle, also handgrab

Bent round bar of various sizes for use above access openings, on miscellaneous access opening covers or on hatch covers.


A long bar fixed to the side of a passage or stairs for holding onto it.

Harbour dues

Various local charges demanded from all seagoing vessels entering a harbour to cover maintenance of channel depths, buoys, lights, etc.

Harbour master

A person usually having the experience of a master mariner and having a good knowledge of the characteristics of the port and its whole area.

Harbour, haven

Any place which offers good anchorage and fairly safe station for ships, or where ships can be sheltered from wind and sea.

Hard coating

A coating which changes chemically during its curing process; normally used for new constructions.


In two-component materials, the component that produces chemical reaction linking the molecular chains of the binder into a more rigid structure.


A type of steel heat treatment. The steel is heated to 850-950°C and then rapidly cooled by quenching in oil or water.


1. The ability of a material to resist plastic deformation. 2. A measure of the ability of a sample of water to produce lather with a soap solution.

Hardness of the dry paint film

The ability of the dry paint film to resist mechanical impacts as scratching or penetration by hard object.


Generally, harmonics are oscillations in the base power frequency.

Hatch coaming

Vertical plating bounding a hatch in order to stiffen its edges and resist entry of water to the space below.

Hatch cover

A large steel structure fitted over a hatch opening to prevent the ingress of water into the cargo hold. It may also be the supporting structure for deck cargo.

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