I decided to take the PADI Self-Reliant Dive course. Learning how to be a self-reliant diver teaches a good set of skills for any diver. But, of course, the real goal is solo diving safely.

What's my motivation for solo diving? It's simple, I want to dive at my own pace.

Buddy diving is great but inevitably I want to stop during a dive and hang out in one spot to take photos and videos. Far too often I look up and my buddy or group have continued to cruise along and are almost beyond visibility. I have to hustle to catch up, quickly bypassing even more interesting sites.

Hence, I'm taking these first steps towards being a self-reliant diver and solo diving.

The course began with some classroom training and a knowledge assessment. This covered a lot of good stuff like self-rescue, self-reliant skills/mentality, equipment redundancy, planning, and self-management of dive emergencies. It was a mix of fundamentals, calculations, and common sense.

The course also requires three training dives. The biggest change for me is the addition of a pony bottle to my gear. The pony bottle is a redundant and independent air supply. It's really just a small version of a regular scuba tank.

The first training dive was today and had a number of objectives, mostly performing the usual skills but with all of the redundant equipment:

1. Buoyancy check
2. 200 metre surface swim
3. Demonstrate neutral buoyancy at depth by hovering
4. Switch to the redundant air supply (pony bottle)
5. Swim to calculate my surface air consumption (SAC)
6. Deploy a surface marker buoy (SMB) on reel with a line

The first few skills were easy and completed within the first 10 min of the training dive. The next few were where things got a bit more interesting.

Part of #4 was that the instructor had to simulate a free flow of my regulator while I switched to the pony bottle. She simulated the free flow simply by pressing the purge button on my regulator while it was still in my mouth. This isn't something that's ever happened to me so that in itself was a new experience.

I was still breathing through my regulator as it free flowed but I had also begun to lose control of my buoyancy. To manage it I really had to stop, breathe, think, and act. I still had some air in my BCD so I calmly dumped it and got my buoyancy back under control. Once that was taken care of, I switch over to the pony and breathed off of that for two minutes to complete the objective.

Your SAC is simply your rate of air usage from your tank and the next objective was to do a swim to calculate it. I swam for 10 minutes at 10 metres, noting my starting (140 bar) and ending (175 bar) air pressure.

Here's the formula:

SAC = ((bar used) * (cylinder volume in litres) / ((depth + 10 metres) / 10)) / time

We put it on a whiteboard after the dive.

So my surface air consumption is 19.25 litres/minute. Call it 20 litres/minute to be on the safe side.

The final objective turned out to be the trickiest. It's been a while since I've deployed my SMB so I was actually really looking forward to the practice. Unfortunately I couldn't release my SMB from where I had secured it on my BCD. Not great but the instructor lent me hers to complete the objective.

She had a large SMB that needed to be inflated by inserting a regulator and purging air into it. No problem I thought, I've seen people do this many times before. I held the reel, took my secondary regulator out, popped it in the SMB, hit the purge valve forcing air into the the SMB to inflate it, released the reel, and the SMB shot towards the surface as the line unreeled.

However, my secondary regulator starting free flowing for real. Air was pouring out at the maximum rate. We were maybe half way through the dive so I still had a fair amount of air left but it was rapidly escaping. I tapped the regulator like I've done before on the surface to stop a free flow but that didn't work. None of the little tricks to stop a free flow worked.

I took what I figured was the best course of action at the time and began an ascent. I went at a reasonable pace but probably faster than I normally would have. My computer never beeped at me to slow my ascent rate so I must have kept it within safety parameters. At the surface the free flow continued until my tank was spent. I was pretty tangled up in the line from the reel to the SMB and the instructor had to untangle me. Not the best end to the dive.

But looking back on it, it was good experience. A real (and serious) problem in relatively controlled conditions and close to the surface. I handled it well but after the dive during the debriefing, I realized I could have handled it better.

I should have switched to the pony bottle almost immediately after the real free flow began and then attempted to fix the free flow. To fix the free flow I could have reached behind my head to turn off the air to my own main tank and then turn it back on. Whatever the result I would be breathing comfortably off of my pony bottle.

So it turned out to be an great learning experience and an excellent reminder to stop, breathe, think, act in adverse conditions. Also an excellent reminder to get my regulator serviced, which I did immediately when I got back to the shop.

Location: Wellington, Taputeranga Marine Reserve, New Zealand

Dive Number:   140 Bottom Time: 29m Time In: 2:33 p.m. Tank In: Max Depth: 10.20 ft Table Used:

Mix:   Air Safety Stop: Time Out: 3:02 p.m. Tank Out: Average Depth: 8.00 ft Start Pressure Group:

Surface Interval:   End Pressure Group:

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