Glossary of Common Boating Navigational Terms

The following is a list of maritime navigational terms commonly used by boating enthusiasts and found in nautical reference materials.

Abeam

To be on the side of a boat that is perpendicular to its keel, at a right angle. Etymology: The term “abeam” likely originates from the Old English word “onbæme,” which meant “on the beam” or “on the side.”

Bearing

The direction of an object or a fixed point expressed in degrees relative to the direction of the boat’s bow. Etymology: Derived from the Old English word “beran,” which means “to bear” or “to carry.”

Buoy

A floating marker or beacon anchored in water to indicate navigational hazards, channels, or other points of interest. Etymology: Derived from the Middle Dutch word “boeye,” meaning “a float” or “a signal.”

Dead Reckoning

The process of estimating a vessel’s current position based on its last known position, course, and speed, without considering external factors like wind and currents. Etymology: The term comes from the phrase “deduced reckoning,” which evolved to “dead reckoning.”

GPS (Global Positioning System)

A satellite-based navigation system that provides real-time positioning, velocity, and time information anywhere on Earth. Etymology: Acronym for Global Positioning System.

Knot

A unit of speed, equal to one nautical mile per hour (approximately 1.15 statute miles per hour). Etymology: Derived from the Old English word “cnotta,” meaning “a fastening” or “a tie.”

Latitude

The angular distance, measured in degrees, minutes, and seconds, north or south of the equator, used to determine a vessel’s position in the north-south direction. Etymology: From the Latin word “latitudo,” meaning “breadth” or “width.”

Longitude

The angular distance, measured in degrees, minutes, and seconds, east or west of the Prime Meridian, used to determine a vessel’s position in the east-west direction. Etymology: From the Latin word “longitudo,” meaning “length.”

Nautical Chart

A specialized map used for navigation at sea, which displays water depths, navigational aids, hazards, and other important information for safe sailing. Etymology: Derived from “nauticus” (Latin) and “charta” (Latin), meaning “pertaining to ships” and “paper” respectively.

Sextant

(Archaic) A navigational instrument used to measure the angle between a celestial object, such as the sun or stars, and the horizon to determine the vessel’s position. This is an archaic term/device, rarely used in modern boating, but often cited in historical and referential texts. Etymology: From the Latin word “sextans,” meaning “one-sixth,” as the instrument covers one-sixth of a circle.

Tide

The regular rise and fall of seawater caused by the gravitational forces of the moon and sun. Etymology: Derived from the Old English word “tīd,” meaning “time” or “season.”

True North

The direction pointing towards the Earth’s geographic North Pole, as opposed to magnetic north. Etymology: The term “true” indicates an alignment with the Earth’s rotational axis, providing a fixed reference for navigation.

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Understanding common nautical navigation terms is essential for safe and efficient boating. Always practice responsible navigation and ensure you are familiar with local regulations and guidelines when navigating waterways.