Marine Navigation: Nautical Terms explained in simple terms

Marine Navigation: Nautical Terms explained in simple terms
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Basic Directions

The diameter around which the earth rotates is “The Axis of Rotation”. Where it meets the earth form the Geographic North and South Poles

The direction in which any point on the earth’s surface is carried (because of the earth’s anticlockwise rotation) is called East. The opposite direction is West.


ABEAM - At right angles to the navigating bridge of a ship.

AFT - Toward the stern of the ship

ABAFT - Between abeam and astern.

AHEAD - In a forward direction, ie in the direction of the bow (front) of the ship

ASTERN - In back (stern) of the ship, opposite of ahead.

PORT: The left of the ship, facing the bow OR, a harbour.

STARBOARD: The right side of the ship, facing the bow.

Basic Nautical terms used when sailing


AGROUND - Touching or stuck to the bottom of the seabed.

AIDS TO NAVIGATION Artificial objects to supplement natural landmarks used for navigation. eg buoys, lighthouses etc. (see pic)

ANCHORAGE A place suitable for anchoring in relation to the wind, seas and the sea bottom.

BEARING - The direction of an object relative to the heading of the ship. Measured in degrees.

BUOY - An anchored float used for marking a position on the water, or for mooring. (see pic)

DRAFT - The depth of water a ship draws.

FATHOM - Six feet.

GIVE-WAY VESSEL A term used to describe the vessel which must yield in meeting, crossing, or overtaking situations.

STAND ON VESSEL A term used to describe the vessel which may NOT yield in meeting, crossing, or overtaking situations.

TIDE - The periodic rise and fall of water level in the oceans. See

Chartwork and miscellaneous terms

Major ocean currents in the world

Compass Rose

Position fixes (circled parts)

See also

A COMPASS ROSE (see pic) is a easy means- for a navigator- of finding direction on the chart and also plotting a ship’s course, besides taking bearings (angles) of objects with a compass. Called because it looks like a rose petal opened up, it is graded from 0 degrees to 360 degrees, with 0 being North, 90 being E, 180 being S and 270 being W.

SOUNDING A measurement of the depth of water.

HEADING (HDG): The direction in which the ship is pointing in any instant.

SPEED(S): The speed of the ship through the water. Always recorded in knots (a sea mile is a knot, and is 6080 feet)

Water in motion is called CURRENT. (see pic)

SET: The direction in which the current is flowing.

DRIFT: The speed (in knots) of the current.

COURSE: The direction in which a vessel is steered or is intended to be steered (direction through the water).

FIX The ship’s position, plotted on the chart by celestial or land bearings to a known point. (see pic)

COURSE is the intended horizontal direction of travel measured from 000 degrees clockwise through 360 degrees, where 000 is North.

The Purpose of the COLREGS (Collision Regulations at sea) is to cover, by international convention, anti collision rules any ships belonging to any nationality will follow at sea. Also called ROR or Rules of the Road.


Currents diagram from