Rolling a vessel, that is slightly ice-bound, so as to break the surface ice around her. May sometimes be done when a vessel is lightly aground, but not ice-bound.

A tiller or a wheel generally installed on the bridge or wheelhouse of a ship to turn the rudder during manoeuvering and navigation. It is in fact the steering wheel of the ship.

Said of a vessel when stopped and lying near the wind in heavy weather. See Heave To

Is the ratio of the computed isentropic temperature rise to the measured total temperature rise during compression.

Equipment used for serving meals.

A support fixed on the front part of a chassis (which is retractable); used to support the front end of a chassis when the tractor has been removed.

The average level of the oceans, used when finding water depths or land elevations.

To leave a ship without authority (deserting).

Condition of a sailing ship when all sails have been taken down in a severe storm, very often a hazardous undertaking if there is a high sea running.

The operation of taking a sounding with the hand lead (to find bottom).

A warning from aloft (heads up).

Sling of various types used for lifting vehicles on to and off general cargo ship.s

A machine employing two or more stages.

see Gybe

The air compressor continues to run, usually at full RPM, but no air is delivered because the inlet is either closed off or modified, not allowing inlet air to be trapped.

A watch tackle (small, handy block and tackle for general use).

The increase in pressure in the discharge header that develops as a result of flow after the pressure relief device opens

To stand at the mast and pull down on a halyard as another crewmate winches it in.

CFM flowing through the compressor inlet filter or inlet valve under rated conditions

The course of a vessel after magnetic variation has been considered, but without compensation for magnetic deviation.