HOW TO ASCEND
The key words here are anticipation and control. Before you ascend, dump a little air from your BC and, while you’re on the way up, always be aware of the need to dump a little more from time to time.
Do this pro-actively rather than reacting when you feel the expanding air starting to pull you up too fast. Yes, it will mean having to use your fins a little during the ascent, but it means that you, not your BC, are controlling the ascent.
Before surfacing, as long as you have air left and sea conditions don’t make it dangerous to stop (as when drifting towards an area with a downcurrent), you should make a 3-5 min safety stop at a depth between 3m and 6m.
The actual depth doesn’t matter, nor does the exact time you stay there. Pick somewhere comfortable and hang out for a while. If there is a lovely patch of coral on the reef at 4m to gaze at, then that’s where you spend a few minutes.
Or, if you’re on an anchorline and there is a large knot of rope at 6m where a bunch of baby fish have made a temporary home, wait there, enjoying watching them dart about.
When you are ready to surface, up you go – but, not so fast! The main reason you did a safety stop was to help your body decompress more efficiently. However, no matter how long it took, tiny bubbles are still coursing around your body.
Tests show that a diver experiences maximum bubbling 30 minutes after surfacing from a dive. So, even right at the end of the dive, keep the concept of ascending slowly and safely in mind.
This means that you don’t just finish your stop and shoot to the surface through that section of the water column where the pressure difference is greatest. The final part of your ascent is where you need to move even more slowly.
The application of a little maths makes this clear. If your safety stop was at 4.5m and the recommended maximum ascent rate is 9m per minute, it should take you at least 30 seconds to get from your safety stop to the surface.
In practice, try to take at least a minute. Sometimes, this may be difficult to judge, especially as the distance is comparatively short and many computers show only minutes, not minutes and seconds.
So, either count seconds in your head (one elephant, two elephants) or watch two minutes click over on your dive-computer before you pop your head up clear of the surface.
A minute can feel like a long time but, with practice, you’ll get the idea of the right pace to go at.
Take the art of ascending seriously. It’s something that is often neglected but is a technique well worth mastering.
Read more from Simon Pridmore in:
Scuba Confidential – An Insider’s Guide to Becoming a Better Diver
Scuba Professional – Insights into Sport Diver Training & Operations
Scuba Fundamental – Start Diving the Right Way
Scuba Physiological – Think You Know All About Scuba Medicine? Think Again!
All are available on Amazon in a variety of formats.