Section 6

Getting Your Bearings

6.5

Clearing Bearings

A clearing bearing is a line of position that is plotted when a navigator wants to avoid a submerged or otherwise hard-to-see hazard.

Plotting a Clearing Bearing

From a charted visible object, a line is plotted that clears the danger to be avoided. This is the clearing bearing. Its direction is noted along with whether, to clear the hazard, bearings taken on the object should be not more than (NMT) or not less than (NLT) the clearing bearing.

To avoid the rocky shoal, a line is plotted to clear the submerged hazard and extended to the flashing green light: the object of the bearing. The direction of the line is the clearing bearing.

The white boat is clear to steer towards the light as its bearing on the light of 300° is not more than the clearing bearing of 310°.

A bearing taken from the gray boat is more than the clearing bearing, so this boat is not yet clear of the unseen rocks.

Like other bearings, clearing bearings are taken using a hand-held compass.

The bearings are labelled as True, but it's good idea to also label them as Magnetic.

clearing bearing

 

Clearing bearings can be very helpful for sailors when the wind direction requires tacking.

As the boat tacks upwind, as long as the boat stays within the two clearing bearings it will avoid the submerged rocks between the two islands.

This diagram also illustrates that clearing bearings are useful whether the boat is travelling away from, or toward, the object of the bearings.

clearing bearing-tacking

 

See Sail Canada plotting and labeling of a Clearing Bearing.

 

 

The Sail Canada Basic Coastal Navigation Standard
9 Correct bearings between true, magnetic, and compass.
10b Plot a position fix based on two or more bearings.
10c Plot a position fix based on one bearing and one range.
10d Use clearing bearings in piloting.
16 Use Sail Canada's Uniform Navigation Symbols and Terms

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