A challenge: orient yourself underwater
Human beings began to use a compass to guide their travels as far back as the ninth century. But there is no better way to find one’s path than having the necessary knowledge of navigation.
The compass was invented in Asia, where a needle magnetized to an aerial space and, later, to water, was used to mark the magnetic north of the Earth. If you know where the north is, then you can find the rest of the cardinal points.
What if I told you that handling a compass while diving can be one of the most complicated things to try to do? Starting with your first open water diving course you should become acquainted with its basic use, get better at it in the advanced course and, of course, keep improving on your own whenever you go diving anywhere in the world.
Are there different models of underwater compasses?
Different models are available, but the most reliable ones have oil inside to better withstand the pressure and ensure smooth movement of their internal parts. In ancient times, as noted, they contained either water or air, making them a bit more imprecise.
There are many sizes and different fastening systems, involving the wrist, with extensible hooks and systems built into the diver’s regulator set (instrument console), and different prices.
At present, most compasses have luminous material to better reflect sunlight or the light from your lantern, which is quite useful for dark days or night-time immersions. Starting at about 30 euros, you can find good models on the market.
The first thing, before navigating, is to know the right position for using the compass and to identify the parts of the compass.
As you can see in the picture, the arm wearing the compass must be bent at a 90-degree angle, and holding the elbow on the diver’s other fully outstretched arm, so the compass is directly under the diver’s eyes. So there will be no errors in finding the right direction.
The compass must fit tightly on the diver’s wrist, in a stable position. If you hold the compass directly in your hand, without fastening it to your wrist, keep it as horizontal as possible.
What part does an underwater compass have?
– Main or top window: This is where we look in and find information in degrees, with the desired degree at the top of the direction line. All compasses have 360 degrees and mark the four cardinal points.
– Front window: It must always face inwards, towards your body, so you can see the degree information just as you can in the top window. The information shown in the front window will always be the opposite of that shown in the main or top window. Plan this with your partner when setting the direction, and do it using the chosen line.
– Bezel: Any good compass has to have a bezel, the upper spinning wheel with the 360 degrees engraved in it, which is used to set starting directions and make turns in underwater navigation.
– Rhumb line: This line can be marked in different colors. Here a diver must set the desired bearing in degrees at the top. It is important to do this correctly, because a small deviation of just a few degrees can take you where you never wanted to go.
There are also small compasses integrated in a diver’s gear, like computers or directly in the buoyancy controld device, with elastic systems or clamps. These are a bit cheaper and more imprecise, but they are equally valid if you have a little bit of experience in handling them. Some models are too small to have a bezel.
If you’ve got this far, it’s because your’re really interested in navigation with a compass. Remember that you will need a lot of practice until you can master a compass and, above all, find your way.
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