The difference in pressure between the opening pressure and reclose pressure of a valve. May be expressed in percentage of set pressure or "psig".

The piston only compresses air with its stroke in one direction.

Small, circular sheets of newly-formed ice that do not impede navigation.

Snappy, seamanlike; a smart ship is an efficient one.

Heavy canvas used as a covering.

To carry sail to the full limit of strength of masts, yards, and tackles.

Running directly before wind and sea.

A purchase (block and tackle) for hoisting a boat to its davits.

A sudden squall of wind accompanied by lightning.

The water level used to record data on a chart. Usually the average low tide water level. It is the level below which depths on a chart are measured, and above which keights of a tide are expressed.

Short lengths of line attached to the sail used to tie the extra sail out of the way when reefing.

Pounds per square inch, gauge. Pressure indicated by a pressure gauge.

A vessel's station bill showing duties of crew.

Response to an offer which varies the terms or conditions of that offer.

A valve which enables pressure to be reduced, or kept constant at a desired level.

A blast of from 4 to 6 seconds' duration.

The number of revolutions per minute of the compressor shaft.

Waterproof clothing.

Two half hitches around a spar or post. Easy way to make a line temporarily fast to a piling or post. The clove hitch can jam under heavy tension, making it difficult to untie. Worse, is its tendency to untie itself when subjected to repeated strain and r ...

A common measurement of the internal volume of a ship with certain spaces excluded. One ton equals 100 cubic feet; the total of all the enclosed spaces within a ship expressed in tons each of which is equivalent to 100 cubic feet.