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Everybody who passed the boating licence exam had to learn about the compass. This is an ancient and yet still current navigational instrument especially useful for offshore sailing. A traditional compass is unrivalled by no electronic device. Its simple magnetic needle is able to show the current course or the boat’s position in case of triangulation in the total absence of electricity and under any conditions. It is no coincidence that almost every boat, including small-sized ones, is provided with a compass.

Although mandatory for boats allowed to navigate beyond 6 miles, this instrument is always of vital importance and is a must on board. All of this said, this article will focus on a special compass every yachtsman can’t do without: a hand-bearing compass. This is a hand-held compass that has forward and rear sight vanes with cursor lines. It is used to measure the magnetic direction from the boat to charted landmarks (e.g. a landmark on the shore like a mountain or a tower). Here is one of the many available on the market: Prisma bearing compass and case (osculati.com).

A hand-bearing compass is essential to fix your boat’s position (by tracking landmarks) but it is also an invaluable aid to be aware that your boat and another one are on crossing courses and therefore risking a collision. Nowadays, thanks to on board electronics, latitude and longitude details can be read on a GPS’s display. But if we talk about correcting for the boat’s heading by cross-referencing the obtained bearing, well, the matter changes completely.

It is well known that the most practical and widespread way to check if your boat and another vessel are on crossing courses is to stand by a stanchion or a shroud (i.e. a fixed structural element of the boat) and “align” it to the bow of the boat you are watching without changing course or speed. If the bearing is constant – which means that the ship viewed from the deck of your ship is getting closer while maintaining the same bearing – a collision will occur. If the bearing changes, the other boat will either go in front of or behind your boat and in both cases you will be clear of a collision.

However, this practical and quick method is not free from defects. Rocking and pitching due to rough sea conditions may disturb bearing or prevent a correct evaluation of the situation, which can be highly risky. The same bearing detected by a hand-bearing compass reduces evaluation risks. Point the hand-held compass at the approaching boat or ship while staying at a fixed element of the boat (always the same). The exact degrees with reference to your boat and its position line can be read through the magnifying prism (or on the display in case of electronic compasses). Repeat the bearing after some time and, as told before, evaluate the results: if the bearing is constant or it has only slightly changed, the two vessels are on crossing courses.

A hand-bearing compass is a practical, very handy, cost-effective and highly reliable instrument. It is an invaluable aid to navigation. Charting enthusiasts who love keep on training (always highly recommended) may fix their boat’s position. As a hand-compass, bearing compasses are held above the metal parts of the boat and this is why magnetic bearing is considered to be free from deviation. Binoculars fitted with a compass combining magnifying and bearing functions are also available on the market, such as Professional binoculars 7×50 fitted with compass (osculati.com). They are of course less user-friendly than a compass due to size and weight and yet combine two important functions in one single instrument. It is up to each user to decide on the most appropriate option. Moreover, binoculars are mandatory for boats allowed to navigate beyond 12 miles.

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