Lubber line
Encyclopedia
A lubber line is a fixed-line displayed on a compass
binnacle
or radar
plan position indicator
display pointing towards the front of the ship or aircraft and corresponding to the craft's centreline.
The line represents 0 degree
s and is therefore the zero-point from which relative-bearings are measured, e.g., "twenty-degrees to port".
Compass
A compass is a navigational instrument that shows directions in a frame of reference that is stationary relative to the surface of the earth. The frame of reference defines the four cardinal directions – north, south, east, and west. Intermediate directions are also defined...
binnacle
Binnacle
A binnacle is a waist-high case or stand on the deck of a ship, generally mounted in front of the helmsman, in which navigational instruments are placed for easy and quick reference as well as to protect the delicate instruments. Its traditional purpose was to hold the ship's magnetic compass,...
or radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
plan position indicator
Plan position indicator
The plan position indicator , is the most common type of radar display. The radar antenna is usually represented in the center of the display, so the distance from it and height above ground can be drawn as concentric circles...
display pointing towards the front of the ship or aircraft and corresponding to the craft's centreline.
The line represents 0 degree
Degree (angle)
A degree , usually denoted by ° , is a measurement of plane angle, representing 1⁄360 of a full rotation; one degree is equivalent to π/180 radians...
s and is therefore the zero-point from which relative-bearings are measured, e.g., "twenty-degrees to port".