A reagent is a substance or compound added to a system to cause a chemical reaction, or added to test if a reaction occurs.

A mark or place at which a vessel comes under obligatory entry, transit, or escort procedure.

A rechargeable battery, storage battery, or secondary cell, is a type of electrical battery which can be charged, discharged into a load, and recharged many times, as opposed to a disposable or primary battery, which is supplied fully charged and discarded after use

An alternating motion between two extreme points on a fixed path, e.g. up and down motion.

A engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert pressure into a rotating motion.

Reciprocating pumps move the fluid using one or more oscillating pistons, plungers, or membranes (diaphragms), while valves restrict fluid motion to the desired direction.

In electric power distribution, automatic circuit reclosers are a class of switchgear which is designed for use on overhead electricity distribution networks to detect and interrupt momentary faults.

Recognised Organisation “RO”, an authorized organization that performs statutory requirements on behalf of a vessel’s flag state. While often a Classification Society, in the IMO DCS, independent verifiers are authorized by some flag states.

An organization with appropriate expertise in security and anti-terrorism matters recognized by the Administration and authorized by it to carry out assessment, verification, approval and certification activities...

A recommended exposure limit is an occupational exposure limit that has been recommended by the United States National Institute for Occupational Safety and Health.

The document for recording all parameters changes, including components and engine settings, which may influence NOx emission of the engine.

Power conversion from AC to DC.

A rectifier is an electrical device that converts alternating current, which periodically reverses direction, to direct current, which flows in only one direction.

Recursion is a method of solving a problem where the solution depends on solutions to smaller instances of the same problem.

Redox (reduction–oxidation) is a type of chemical reaction in which the oxidation states of atoms are changed.

A valve which is designed to maintain a lower constant fluid pressure at outlet, regardless of the inlet conditions.

Reduction is the gain of electrons or a decrease in the oxidation state of an atom, an ion, or of certain atoms in a molecule (a reduction in oxidation state).

Equipment used to convert the output shaft revolutions of the main engine to those required to rotate the propeller.

The provision of equipment or components which are surplus to operational requirements in order to continue operation after a failure.

Duplication of various machinery and systems forming a part of the propulsion system.