In navigation, the boat's trajectory is subject to multiple variations between the planned route and the route actually followed. This can be linked to the wind, the current, the state of the sea, the quality of the helmsman, etc... It is therefore essential to "take stock" regularly, i.e. to establish with more or less certainty the position where one is at a given moment. Depending on the dangers present on the water, the proximity of the coast or the available landmarks, you may choose to take a position every half hour, every hour or every 3 hours.
One of the basic techniques for making the point is to use bearings. We will need a " bearing compass " for this.

THE BEARING COMPASS

In pleasure boating, it is a portable compass that allows you to aim and "take" the magnetic direction of a remarkable point located on the coast or at sea (lighthouse, beacon, bell tower, water tower, antenna, ...). We call this remarkable point a "bitter".

At Picksea, we highly recommend the VION brand of bearing compasses. They are indeed much more accurate than other brands and even beginners will get very good results with these compasses.

Recommendations for using a bearing compass: beware of magnetic disturbances that can distort measurements (metal glasses, cell phones, proximity to the engine or a VHF antenna, etc.) and if the sea is rough, set the compass at the point on the boat that moves the least (for a sailboat, for example, this is often the mast step).

compas de relèvement axium de Vion

"Taking and plotting a bearing" consists of measuring the magnetic direction of a landmark on the landscape with a bearing compass and then plotting the bearing on the chart from the symbol of the measured landmark (using a ruler or protractor).
méthode prise de relèvement

THE DIFFERENT METHODS OF TAKING A BEARING

Point by Three Bearings

Measure the bearings of three prominent landmarks that have been marked on the chart and identified on the landscape. With the navigation ruler, we then plot these three bearings on the chart.

Why are three bearings necessary? Logic would dictate that two bearings would be sufficient, but at sea there is always the possibility of a measurement error. It is therefore wise to "make sure" by taking a third bearing.

The point by bearing and alignment

In this situation, being on an alignment of two identifiable landmarks on the chart, it is sufficient to take only one bearing to determine its position.

point avec relèvements

To learn more, Picksea invites you to discover our Youtube channel, PickseaVideo.