ORIENTATION IN UNDERWATER DIVING

Let anyone who has never been lost in diving throw the first stone! For supervisors, knowing where to find their way is a necessity, and a very legitimate anxiety for those who will soon leave the instructor's fins to dive independently. We have therefore decided to give you some advice, and to remind you of the basic rules of orientation. Guarantees of safety, and of diving pleasure.

MORE OR LESS SERIOUS CONSEQUENCES

Luckily, getting lost in a dive is not always synonymous with disaster, but can nevertheless have very unpleasant consequences: going back up to 500 meters from the boat, with an empty tank because you have been around for a while a lot of effort when the conditions are right, you will just get back on the washed out (and usually shameful) boat. But it can turn into a nightmare if there are waves, current, or an ugly little mist that destroys all visibility. And the training of many divers remains extremely limited in this area.

WHERE AM I ?

On the surface aboard the boat, unless you are diving in the open sea out of any visual cue, take the time to observe your surroundings, this could be very useful, for example on a very jagged coast if you get lost and you go up in a cove: the Genoese tower, where was it in relation to the boat? And this antenna, did I see it or not? Likewise, if the visibility allows it, try to record what you can note from the bottom, from the boat: I am on the port side of this large tongue of sand which sinks towards the coast, or very close to this dry which is flush with the surface and seems to widen at the base ...

THE INTEREST OF A GOOD BRIEFING

Do not neglect the briefing given by the management team: the instructors have dived there dozens, if not hundreds of times, and their knowledge of the area will save you precious time. More and more centers or cruise ships, whether in metropolitan France or at the end of the world, have moreover got into the habit of drawing the dive sites to tell you in advance the possible routes. Do not judge this time spent "on the school benches" unnecessary.

 

SPOTTING "REMARKABLE" ELEMENTS

Be careful: a rock rounder than the others, a small herbarium, a characteristic fault are all elements that should help you orient yourself at the bottom. Do not hesitate, if you are planning a round trip diving pattern, to turn around every now and then to visualize the aspect of the landscape as you should see it when you decide to return. In your head, you will thus draw a kind of mental map of your dive. You can also draw some elements on a submersible tablet, but do not go overboard by diving your nose on a drawing: of course, you will not get lost, but you will not have benefited from anything.

MONITOR DEPTH AND TRY TO EVALUATE DISTANCES

Try, once you are at the bottom, to maintain a fairly constant depth. This will prevent you from going astray, for example by going up five meters to find yourself in front of a big rock that you had not seen on the way and that may disorient you. And unless there is a lot of current, try to evaluate the distance from the elapsed time, always palping in much the same way. If on the return you palm for ten minutes and you still have not spotted the arch in front of which you had taken on the right, do not persist to go further, it is that you are wrong.

USE THE SUN, THE CURRENT, THE BACKGROUND

Try to reactivate your senses! Like an Indian on the trail of game, use the elements around you to try to position yourself by asking yourself simple questions: When I left, what was the position of the sun in relation to me? Just behind ? So to turn back I must now face him (unless you dive for two hours and he has moved a lot). The current, if there is, was it against me or was it pushing me? And if the bottom is sandy, don't forget to just look at the sand ripples: they are necessarily parallel to the coast, and more and more tight as you get closer to the shore.

CHOOSE THE FORM OF ITS COURSE

Traditionally, diving courses revolve more or less around three main forms: the round trip, the simplest and perfectly suited to the exploration of a wall for example, but also the triangle or the square, if the goal of the dive is to go around a coral construction or a dry rock in less tropical waters. The case of drift dives is of course set apart, since it is then impossible to return to its starting point. It is there, when it comes to following more or less the contours of a geometric figure, that the use of a compass can be judicious.

USE INSTRUMENTS

Depending on the diving conditions, especially in the event of poor visibility, or night diving, the instruments can be of great help. But you still have to know how to use it! Do not hesitate to have you explain the operation of your compass if you have one. Once again, as is often the case in diving, there is no need to “pretend you know”. Imagine yourself thirty seconds in the background turning your compass all over the place, wondering what the use of this thing is when you might have had the answer half an hour earlier. Sure, you will have regrets! Obviously, diving using a compass means following a route from the start of the dive, in order to be able to change course afterwards!

IN THE LAST APPEAL

You will sometimes be brought, the amount of air available in your bottle decreasing dangerously (and remember that you must, if necessary, make your bearings), to surface. In calm weather and good visibility, it usually solves the problem immediately, you just have to palm to reach the edge or to sign the boat that will see you from afar and will pick you up. In harsher conditions, waiting before we find you may be long. And if you dive into an area where shipping is important, the risk of accidents is real. Keep calm, do not run out of unnecessary effort, and immediately think if you can inflate your parachute, it will spot you.

FOR THE MORDUS, A DISCIPLINE OF WHOLE

And for the most enthusiastic, underwater orientation is in fact a discipline in its own right, with a commission within the Federation. But there, we change category, and the most experienced practitioners are able to complete complicated courses, without any visibility. For you, it will undoubtedly remain only the means of making the most of your explorations, without wondering with anguish at what time you will finally manage to locate the boat!

Text: Isabelle Croizeau