Smoke can be black, blue, white, yellow or brown in colour. Black smoke is mainly comprised of carbon particulates (soot).

The ratio, of the blade area situated forward of the rudderstock to the total rudder blade area.

A mixture of pollutants, principally ground-level ozone, produced by chemical reactions in the air involving smog-forming chemicals.

Various kinds of commodities usually packed in sacks or in bags, such as sugar, cement, milk powder, onion, grain, flour, etc.

A fitting for securing the end link of a chafing chain, consisting of two parallel vertical plates mounted on a base with a sliding bolt passing through them.

A plate used to direct fluid flow, e.g. the hot gases in a boiler furnace or the oil in a sump tank.

The pressure existing on the exhaust side of a system, e.g. the pressure opposing the motion of an engine piston during its exhaust stroke.

Backing in the form of a ring, generally used in the welding pipe.

A catamaran with unconventionally shaped hulls: two submarine-like floating bodies lie deep under the water surface and thus create the required buoyancy.

A weld pass made for a backing weld

A material or device placed against the backside of the joint, or at both sides of a weld in electroslag and electrogas welding, to support and retain molten weld metal.

The removal of weld metal and base metal from the weld root side of a welded joint to facilitate complete fusion and complete joint penetration upon subsequent welding from that side.

Any individual, generally an officer, who has been designated by the vessel master to be on call if assistance is needed on the bridge.

The return movement of a means of transport providing a transport service in one direction.

A large valve in which a rectangular or circular gate slides across the opening.

A tank provided to receive oily residues coming from the oily water filtering or separating equipment and from the purification of fuel and lubricating oils.

Sludge oil means sludge from the fuel or lubricating oil separators, waste lubricating oil from the main or auxiliary machinery, or waste oil from bilge water separators, oil filtering equipment or drip trays, (MARPOL).

Ejection of sludge from the separator bowl.

The residue from any oil separation process which is usually a mixture of water, solid material and high viscosity oil.

The operation of a ship at a lower speed than normal one in order to save fuel on ballast voyage or when fuel is expensive.