Compensated Compass

A compass which has been corrected for deviation by the employment of magnets.

Crazy Compass. A compass is said to be crazy when the card refuses to indicate the magnetic meridian by flying around and around. This sometimes happens in a violent seaway, and at other times when the atmosphere is heavily charged with electricity.

Demagnetized Compass. A compass needle which has lost its magnetism is said to be demagnetized. Electrical disturbances have been known to effect this.

Dry Compass. A term applied to a compass which is enclosed in an air chamber instead of a liquid one.

Elevated Compass. Under this head come masthead, pole, and tripod compasses. Compasses are elevated in order to get them beyond the influence of the ship's iron, which, being magnetized by induction, seriously affects the pointing of the magnetic needle.

Liquid Compass. A term used in connection with a compass the card of which is enclosed in a chamber filled with thirty-five parts of alcohol and sixty-five parts of distilled water, the freezing point of the mixture being--10 deg. Fahrenheit. Compasses used in Arctic explorations have their bowls filled with pure alcohol. The reason for not filling all compass bowls with an undiluted mixture is that the pure alcohol eats the paint on the card. Sometimes oil is used instead of alcohol.

Masthead Compass. As its name implies, a compass placed aloft in order to remove it from the influence of the iron in the ship's hull, deck fittings, machinery, etc.

Oil Compass. A liquid compass, the card of which floats about in oil instead of alcohol.

Pole Compass. A compass elevated above the deck on the end of a pole, access to it being had by means of a short ladder. It is sought by these means to remove it from the influence of the ship's iron.

Spirit Compass. A compass the card of which floats about in alcohol or oil.

Standard Compass. A compass situated above the deck so that deviation will be reduced to a minimum, and in a good position for observing bearings. It is by this compass that the ship is navigated.

Steering Compass. The compass used by the wheelsman in steering the vessel. The vessel is put on her course by the standard compass, and the point against which at that time the lubber's mark stands on the steering compass is held by the wheelsman.

Tripod Compass. So named owing to the three-leg stand on which the compass is elevated. A tripod compass is, in other words, a pole compass.