SOME ARE CRAZY, SOME ARE DOWNRIGHT WRONG-HEADED…
And, of course, there’s a lot of good information available online, but when it comes to dealing with an OOA situation, be careful.
Perhaps the biggest issue is SPEED: specifically, how fast to surface after an out-of-air event. If you find yourself with nothing to breathe, then your options are severely limited. However, what was troubling about a recent thread in one of the online diving forums wasn’t so much the heated debate about how much contingency gas to carry. Carrying contingency gas in a bailout or buddy bottle, in addition to what’s in your buddy’s tank, is a wonderful idea, of course. The disturbing issue was the talk about how fast to get to the surface after things go wrong?
What confused us was that several posts focused on having enough gas to get a diver back to the surface from 35 metres (about 120 feet) in the two minutes the journey would take. Yes, you read that correctly. Just two minutes to safely ascend from 35 metres to fresh air and the surface.
That makes no sense at all, especially with contingency gas available. In that case, the ascent should be controlled and not at all rushed. That’s the point of carrying extra gas. A bailout bottle is not a licence for speed. Rushing to the surface is unnecessary and unsafe.
Let’s look at the scenario logically. RAID recommends a maximum ascent speed of nine metres a minute during a controlled ascent. (This for most recreational dives) In addition, according to our standard practice, a dive to 35 metres calls for a safety stop at three metres or so for at least three minutes. (Many PDC (personal dive computers) would suggest more depending on the time at depth, but let’s use that for example.). Considering all that, a much safer ascent time would be closer to seven minutes… perhaps a little more!
While it’s important to note, this timing is based on the diver having plenty of contingency gas, and it screams a loud caution: SLOW DOWN, FOLKS.
Surfacing from any dive, especially one to 30 metres (100 feet) or more, carries a real threat… actually, several. Always prioritise a slow, controlled ascent, especially surfacing after deeper dives. Be informed. And speaking of information, if the thought of carrying contingency gas sounds like a great idea, check out our Independent Diver Course.