Frustration or liberation, the ascent to the surface is a crucial moment during your dives. With a bit of training, you’ll discover that properly managing this ascent is not so complicated! You’ll quickly realize that you’ll be able to ascend flippers in the nose.
The Ascent: A Key Moment
The ascent is essential because the decrease in pressure leads to the evacuation of nitrogen accumulated in your body during exploration. At the same time, the volumes of gas present in the air cavities increase. It is therefore crucial to adopt a steady ascent rate without jerks, accompanied by ample ventilation, to avoid decompression accidents and barotraumas affecting the ears, sinuses, or lungs.
Taking References
To estimate your ascent speed, use all the available landmarks, whether they are fixed or mobile. One of the best references, always effective even in zero visibility, is the bubble. When exhaling, a series of bubbles will escape through your regulator. The smallest bubbles, similar to those of champagne, rise at about 15 meters/min. Rather than following all the bubbles, choose one and focus on it until it changes size. If you ascend without surpassing it, your speed is adequate. If you are slightly below this speed, it is not a problem, as long as your dive computer recommends a speed of 10 meters/min. Just make sure you are not in a halt or descending. Other visual references can include a drop-off, an underwater relief, a computer or depth gauge, as well as the boat at the surface or your dive guide, who is your primary speed indicator.
Refining Sensations
Once comfortable, focus on your sensations. For example, the air injected into the middle ear expands, causing a normal slight cracking. If your ears whistle, you may be ascending too quickly. Conversely, if you feel increased pressure, it means you are descending. To remedy this, grab the line, stop the descent, and ascend calmly, hand over hand. Let your senses express themselves. Diving in warm water without a wetsuit, pay attention to the water gliding over your skin and the movements of your hair, whether pinned or floating. Regularly repeat these concentration exercises, even with your eyes closed.
Using the Lung-Ballast
The lung-ballast is essential: it serves as both an accelerator and a brake. To lift off the bottom, take a deep breath, ensuring your balance is correct. If needed, inflate your buoyancy vest to adjust your buoyancy or give a few fin strokes to initiate the ascent. Along the way to the surface, control your speed by modulating your breath. If you cannot slow down, purge your BCD. Anticipate movements, as inertia in water is significant. In general, avoid swimming too much, as you are already pushed towards the surface by Archimedes. Forcing your ascent can lead to breathlessness or, worse, a panicked ascent.
Mastering the BCD
Without mastery, power is useless. You must be able to access your purges with your eyes closed, otherwise, you risk ascending too quickly. To ascend, use both the rapid dump in short spurts and the slow dump in a balanced way. It is advisable to have the reflex of the high-speed dump, always effective in an upright position, by applying small one-second pressures. For the slow dump, regularly release air, raising your arm well to prevent air from getting trapped. Remember that a rapid ascent can be dangerous and may not be enough to stop you; that’s why the rapid dump is essential. If you have dumped too much air, do not reinflate! Instead, use the line or fin slightly to avoid descending again. Important: you must be able to perform a stop at -3m, with the BCD empty and neutral buoyancy. This criterion will help you adjust your weighting.
Training
Practice your movements with the BCD, seated dry, with eyes closed or wearing a mask to develop automatisms. In the water, let your hands glide over the mooring at the appropriate speed while observing, to associate tactile and visual sensations. In open water, accompany your guide by observing the small bubbles: choose one, point to it and follow it for a few meters before moving to another. On the bottom, on the sand, practice your balance with the lung-ballast to better master your ascent. With neutral buoyancy, take a deep breath and watch the bottom recede to get an idea of your speed. Breathe out slightly after lifting off about 50 cm and feel the slowdown related to your exhalations and inertia.
What Speed?
Diving tables recommend an ascent rate of 15 to 17 meters/min, while most computers are programmed between 10 and 12 meters/min. This means you ascend one meter every 4 seconds with the tables and 5 to 6 seconds with a computer. After a stop, ascend at a reduced speed of 6 meters/min, or one meter every 10 seconds! It is unnecessary to make a safety stop after a too-rapid ascent, as it may be counterproductive. Take your time! Keep these values in mind to better manage your speed during training and make the most of your dives.
This article, initially written by Antoine Mettra for the print edition of PLONGEZ!, has been adapted for the web.
Illustration © Franck Girelli.