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Encyclopedia of Marine Technology

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A bar with cut teeth for engaging into a pinion. A linear motion of the bar is then converted into a rotary motion of the pinion.

Rack wire

A variant of the rack and pinion system in which only one panel is propelled by the rack system, the other being opened by a wire led from the driven panel.


1. A distortion of the hull structure caused by a strain from a disturbed sea. 2. The deformation of the container end or side frame as a result of static and dynamic forces parallel to the deck.

Radar (radio detection and ranging)

An electronic navigation aid using radio waves sent out as a narrow beam to detect solid objects around the ship.

Radar plotting

The whole process of target detection, tracking, calculation of parameters and display of information.


A means of sending signals through space using electromagnetic waves generated by high frequency, alternating currents, i.e. 15 kHz to 100 MHz.

Radio direction finder

A radio direction-finding system on board the ship provides the means of establishing the ship position based on the location of fixed transmitting stations.

Radio operator

He maintains and monitors radio, sends and receives messages. Often maintains electronic navigation equipment.

Radio Regulations

The Radio Regulations annexed to, or regarded as being annexed to, the most recent International Telecommunication Convention which is in force at any time, (SOLAS).


A land- or lightship-based wireless telegraph station which transmits a regular schedule of signals, from which mobile receiving stations, such as that on board the ship, may take their bearings to determine its direction in relation to the beacon.

Radiocommunication workstation

A workstation for operating and control of equipment for GMDSS distress and safety communications and general communication.

Radiographic inspection of hull welds, radiography

A nondestructive testing method which reveals internal defects in metal by exposing a film to X-rays or gamma rays passed through the metal.


1. The upper rounded edge of the bulwark. 2. A pipeline, usually containing fuel, which is maintained at a particular pressure or acts as a distribution manifold.

Rail/vehicle ferry ARATERE

Built by HJ Barreras Shipyard in Vigo, Spain, the rail freight ferry ARATERE is intended for the Cook Strait between New Zealand’s North and South islands.

Rain shelters

Lightweight covers introduced for the first time on hatchcoverless container ship NORASIA FRIBOURG.

Raised quarterdeck

A superstructure which extends forward from the aft perpendicular.


The departure from the vertical of any conspicuous line in profile such as a funnel, mast, stem contour, etc.

Rake of keel

Rake of keel is defined as the height the keel raises from the after perpendicular to the fore perpendicular.


1. A hydraulically-operated piston which seals off a well when the blowout preventer is actuated. 2. The piston rod of a hydraulic cylinder as in a ram-type steering gear.

Ramform hull

The concept of the triangular-shaped hull form with an extraordinary wide stern, developed by Roar Ramde and originally adopted for Norwegian Navy surveillance ships.

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