A fixed, annular forward extending duct around the propeller. The propeller operates with a small gap between blade tips and the nozzle internal wall, roughly at the narrowest point.

An abrupt change in direction of plating, frames, keel, deck, or other structure of a ship.

Technology utilizing both the shaft output and thermal output of a diesel engine. The thermal output is used to drive a steam turbine, for example.

A unit of speed, equal to one nautical mile (6,076 feet or 1852 meters) per hour. In the days of sail, speed was measured by tossing overboard a log which was secured by a line. Knots were tied into the line at intervals of approximately six feet.

Knocking in spark-ignition engines occurs when the fuel-air mixture spontaneously and violently ignites ahead of the normal flame front.

A conical valve, opening outward, to close the mouth of a pipe which passes through the side of a vessel below the water line.

The absolute viscosity of a fluid divided by its density at the temperature of viscosity measurement.

The groove or slot in which a key fits. It must be carefully designed to avoid weakening of the shaft or creating an area of stress concentration.

Keyless bore propellers are press fitted on the shaft cone. Oil is injected under pressure between the bore and the shaft by means of pumps feeding a system of grooves in the propeller bore.

A machined metal bar which is used to connect a component to a shaft.

A long hollow, square section forging which screws into the top section of a drill pipe. It is driven by the rotary table and provides the drill pipe with both rotational movement and drilling mud, drilling fluid.

Heavy wooden or concrete blocks on which ship rests during construction or repair.

The principal fore-and-aft component of ship framing, located along the centreline of the bottom and connected to the stem and stern frames.

A new screw propeller with higher efficiency than a conventional state-of-the-art propeller.

A solid, liquid or a gas in which electric field can be maintained with little or no external electrical energy supplied. It is therefore called an insulator.

1. A circular plate made up of two halves. It fits between the rotor wheels of a steam turbine and has nozzles in its upper half.

The propulsion plant developed by Wärtsilä for LNG carriers. It is an electric propulsion with main generators driven by dual-fuel engines that can run on either boil-off gas or MDO.

The temperature below which water vapour in the air condenses.

A stretching screw with two heavy hooks or claws. It is used to secure an anchor in a hawse pipe.

The determination of the location of survivors or survival craft, (SOLAS , Chapter III). See also Lifesaving.