WÄRTSILÄ
Encyclopedia of Marine and Energy Technology

H

248 results

Habitability

marine

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.

Habitat

marine

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.

Habitat destruction

energy

Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species.

Half-cell

energy

A half-cell is a structure that contains a conductive electrode and a surrounding conductive electrolyte separated by a naturally occurring Helmholtz double layer.

Half-life

energy

Half-life is the time required for a quantity to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive.

Halon

marine

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

marine

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

marine

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

Handbook

marine

A short book containing information or instructions.

Handing over

marine

Delivery of the ship to its owner.

Handle, also handgrab

marine

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

Handrail

marine

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

Harbour dues

marine

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

Harbour master

marine

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

marine

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

Hard chrome

energy

Hard chrome, also known as industrial chrome, chrome gona, or engineered chrome, is used to reduce friction, improve durability through abrasion tolerance and wear resistance in general, minimize galling or seizing of parts, expand chemical inertness to include a broader set of conditions (such as oxidation resistance), and bulking material for worn parts to restore their original dimensions.

Hard coating

marine

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

Hardener

marine

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

Hardening

marine

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

Hardness

marine

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.

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