What's a compass? What's it for?
A compass always has a point representing the centre of the circle. The other point has either a pencil or another point, the compass is then said to have "dry points". The pencil can be used to draw circles or arcs. Dry-point compasses are used either to mark a circle or arc in a material with a slight scratch or to transfer a length. The dry-point compass is generally used by sailors, carpenters or stonemasons to measure and/or transfer dimensions.
What about us boaters?
We use it on a paper nautical chart, in addition to the navigation rule. It allows us to measure, control and report our distances and positions.
The navigator expresses the distances on the map in miles. This "nautical mile", also called nautical mile or nautical mile, corresponds to one minute of latitude or 1852 metres.
Our mile will therefore be found on the latitude scale on the right and left of the map. Each mile is itself subdivided into tenths of a mile.
There are different types of compasses
The Lyra compass The shape of the compass makes it easy to grasp with one hand (you press it with one hand to open it). The remaining part of the stroke is available for manipulating the navigation ruler or the pencil. More practical, although with a smaller opening capacity than the straight compass, this lyre compass will find its place on board to assist you efficiently during your navigations.
The right compass it has two parallel branches. To measure large distances, it can open almost completely. But then you'll need both hands to do it.
And don't forget, the compass is often considered the emblem of exact science and mathematical rigour, which is exactly what we do when we navigate.
And we won't forget the faithful compass, pencil and eraser sidekicks ...
