Marine Glossary

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degree

1. A unit of angular measure equal to 1/360th of a circle. 1 degree equals 60 arc minutes and 1 arc minute equals 60 arc seconds.

Angles can be expressed as decimal degrees, such as 45.50º or as degrees and minutes, such as 45º 30'. As a rule, the practical angle precision we use in charing and piloting is one tenth of a minute, ie 45º 30.6' On nautical charts 1º of latitude is the same as 60 nmi.

Note that as navigators we do not want to mix up angles and time, so our notations for angles are 20º 30' 40" and our notations for times are 1h 2m 30s or 1 hr 2 min 30 sec. We want to avoid the (cringeworthy to a navigator) practice of some sports broadcasts that present minutes and seconds with angle notations.

Note too that this means we need (in the nav station) to label lengths or depths as, say, 12 ft 6 in and not write it as 12' 6", which we might do in carpentry work.

2. A unit of measurement of temperature.