A line on the earth's surface that crosses all meridians at the same angle, appearing as a straight line on a Mercator projection chart. Rhumb line navigation maintains a constant compass bearing but is not the shortest distance between two points on a sphere.
Category: Navigation & Seamanship
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Nautical MileA unit of distance used in maritime and air navigation equal to approximately 1,852 metres or 1.151 statute miles.ParallelA circle on the earth's surface formed by the intersection of a plane parallel to the equator.Port (Direction)The left-hand side of a vessel when facing forward (toward the bow).Speed Over GroundThe speed of a vessel relative to the earth's surface, as measured by GPS or other positioning systems.StarboardThe right-hand side of a vessel when facing forward (toward the bow).SternThe rear-most part of a vessel's hull where the rudder and propeller are typically located.
Back to DictionaryEntry updated May 2026