In charge of twelve to four watch. Ships navigation officer. Keeps charts (maps) up to date and monitors navigation equipment on bridge.

A system by which an object such as a compass is suspended so that it remains horizontal as the boat heels.

The component of the radiosonde which includes the modulating blocking oscillator and the radiofrequency carrier oscillator.

Corrosion at discrete sites, stress-corrosion cracking.

Maritime Subsidy Board

Portable Sampling Unit

Cash In Advance.

Turning the wheel or tiller as far as possible

Limber hole of a ship.

A fixed navigation aid structure, visible during the day, used in shallow waters upon which is placed one or more daymarks.

(1) The alternate rise and fall of the bow of a vessel proceeding through waves; also called hobby horsing (2) The theoretical distance advanced by a propeller in one revolution. (3) Tar and resin used for caulking between the planks of a wooden vessel.

Error that can be introduced when not reading an instrument, such as a compass, directly from its front, due to the separation of the indicator and the scale being read.

Threshold stress for stress-corrosion-cracking. The critical gross section stress at the onset of stress-corrosion cracking under specified conditions.

Horizontal

A trade arrangement in which goods are shipped to a foreign buyer without guarantee of payment.

Escort Ship.

The officer on board responsible for the navigation of the ship.

A rope passed round a man in the chains, while sounding.

A measurement of vacuum or pressure that is used to measure the airflow restriction.

A sailboat with its bow pointed directly into the wind, preventing the sails from filling properly and stopping the boat. It can be very difficult to get a boat that is in irons back under sail. also known as "In Stays".