Going Up Nice And Slow: Ascending for Tek Divers
One of the major things that separate recreational diving and technical diving is the ascent at the end of the dive. Simon Pridmore gives you the low down on what is crucial for a succesful technical dive. (Photo by Chris Hellier/Corbis)
A well-executed ascent is crucial for a successful technical dive. Here are a few tips.
DON’T ascend at a speed faster than 9 metres per minute. If your decompression table has no deep stop built in, DO deduct 1 minute from your bottom time and plan for a 1-minute stop midway between the bottom and the first decompression stop required on the tables
DO add a further 1-minute stop at the level below the first required stop
DO open the valve on your decompression gas and deploy the regulator on ascent or at the stop below your planned switch depth
DO start breathing from your decompression gas immediately on arrival at your planned switch depth
DO add 1 minute or 25% of the required stop time (whichever is greater) to all stops between 18 metres and 6 metres
DON’T go directly to the surface on completion of your final required stop at 4.5 metres Instead, DO ascend to 3 metres and perform a 5-minute-stop there
Then, DO take 1 full minute to ascend from 3 metres to the surface
Finally, DO continue to breathe from your final deco gas on the surface and until you take your gear off
For the rest of this article (Asian Diver Issue 4/2014 Vol.133) and other stories, check out our past issues here or download digital copy here.