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Encyclopedia of Marine Technology


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KAPPEL propeller

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


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

Keel blocks

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


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.


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

Keyless fitting of fixed pitch propeller

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.


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.

Kinematic viscosity

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

Kingston valve

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


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


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.


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

Kort nozzle

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.

KOTUG Rotor Tug

Developed and patented by Ton Kooren, the president of Dutch Towage Company KOTUG, the Rotor Tug represents a new concept in tug design.

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