Freediving at the SETT | September 17, 2007

As some of you already know, I’m a qualified PADI dive instructor, and spent a good part of my twenties travelling around Asia, teaching people to dive. During the surface intervals, me and some of my colleague would jump off the side of the boat to practice our breath hold diving. We started just by finning down, but quick progressed to variable weight diving where we’d grab hold of a weight belt to pull us down, and then haul it up afterwards. We weren’t very good, and I’ve later found that this practice was also quite dangerous, but it was fun and killed some time.

I’d never really seen the point of freediving, thinking it was just the preserve of people without access to scuba equipment. That was until we had a couple of French freedivers come out on the boat with us. While swimming round Chumpon pinnacle at 25m, these guys would drop down to the bottom, hang out for what seemed like minutes but was probably only seconds, then break for the surface. I didn’t show it in front of my clients, but I was secretly impressed.

A few years ago I learnt about a local woman who had started teaching freediving courses in Porstmouth, at a place called the SETT. It turns out that SETT stands for “submarine escape training tank” and it’s this huge, 10 story building that houses one of the deepest tanks in Europe. During the week, submariners don safety equipment, jump in an airlock, and practice escaping a downed sub from 30m. At the weekend, they rent it out to a company called Deeper Blue, who teaches freediving courses there.

I read about one of these courses in a dive mag and it sounded fun. I’d had it at the back of my mind for a while now, so when a space because available at short notice, I jumped at the chance.

Walking off the ferry from Portsmouth to Gossport, you could see the SETT towering over all the other buildings in the area. Wandering towards the naval base I couldn’t help thinking how tall the place looked, and imagining what it would be like looking over the rim and into the waters below. I didn’t have to wait for long as.

After a quick safety briefing, 8 eager students filed into the lift and up to the tenth floor to check out the SETT. Looking into the abyss below filled me with a mixture of excitement and dread. I’ve been to 30m plenty of times, but always with a tank on my back. Looking into the murky depths, you could barely see the bottom, let alone imagine yourself swimming down there and back on a single breath. I decided at that point that I’d be happy to hit 15m, and anything more was a bonus.

The two days fell into a natural routine. You’d start with a classroom session where you’d learn more about the theory and practice of freediving. Being a scuba instructor, much of this was familiar to me. However it also reminded me how much I’d forgotten. You would then move onto the first pool session of the day, followed by lunch, another classroom session and then the final pool session.

The first pool session started with a static apnea warm-up on the surface. This involved “breathing up” to make sure you were relaxed and had enough air in your system, and then simply holding your breath with your face in the water. I started at 1min 30sec and then 2min. On the second tank session I did 2min 30 sec, and by the end of the weekend I reckon I could have pushed it to 3min.

Next we practised our pulldowns, which as the name would suggest, involved us holding our breaths and pulling ourselves down to a fixed depth. The whole point of the day was to start building up our confidence, so I did a quick pull-down to 5m and then a couple more to 10m. After lunch we increased this to 15m, and by the end of the day I was managing pull downs to 20m.

After warming up on the second say with a static and a moderately deep pull-down, we graduated to the freediving fins. Known as constant weight freediving, this discipline involved swimming down to depth and back again without the assistance of a rope. The fins allowed you to get down and back much faster. However, because you were expending more energy and building up more CO2, it became increasingly difficult to hold your breath.

I did a couple of 10m practice dives, before heading for 15m. Unfortunately the increased speed of decent, combined with the previous days diving and my less than expert technique started to take a toll on my eardrums. Equalisation had become increasingly difficult, to the point where it was downright uncomfortable. I eventually made it back down to 20m, but knew that the elusive 25m mark was beyond my bruised and battered eardrums. I don’t normally have equalisation problems, so felt that by body had let me down a little. However I felt confident that I had the lung capacity to hit 25m and possibly even 30m once I’d had chance to rest my ears.

Apart from equalisation problems, my biggest issue was unlearning techniques that have become second nature from diving. Things like exhaling on ascent or body positioning in the water. So I definitely head back to the SETT to work on my technique and aim for the bottom of the tank. I may even consider a freediving holiday to Egypt at some stage.

Form more info on freediving at the SETT, check out some of these links.

Posted at September 17, 2007 5:12 PM


Jernej said on September 17, 2007 7:35 PM

Ah, another convert to this wonderful sport ;)

I’ve been freediving on every summer vacation ever since I was a kid but of course the depths increased only slowly. I was probably 15 or 16 when I finally broke the 15m barrier and I’ve pushed it to 35m a few months ago. On that particular occasion I could go even deeper if: 1. the wall went further down & 2. I had some assistance on the surface (I didn’t risk pushing my luck).
Curiously enough… two days later I could barely hit 20m. I just couldn’t go deeper, I didn’t have any air left to equalise.

My main problem is that I usually have some difficulty equalising unless my head is about level with my lungs (leftover damage from an operation I had when I was a kid) which slows me down considerably. Second one is scuba diving… as you correctly point out it is dangerous to freedive after scuba diving as the nitrogen bubbles re-compress and decompress very quickly. Other than taking a few days off just for freediving I don’t get that many chances to practice going deep (static and dynamic apnea in the pool are entirely different beasts).

I’ve been helping a few friends go beyond their previous limits and it quickly became clear to me that you can teach pretty much anyone with normal abilities to go to 15m in a single day. 20-25 usually takes up to a week but going beyond that takes a lot more practice and experience.

Here’s a video you might want to check out before your egyptian vacation:

Andy Budd said on September 17, 2007 7:52 PM

That’s insane!

Scott Powers said on September 17, 2007 8:35 PM

I can’t say I’ve ever been diving. It sounds like a real blast. I imagine it’s much like riding a motorcycle on some levels. I imagine the free feeling is much the same. Probably not the most common analogy but I ride fairly often so I guess that’s the easiest way for me to understand it.

Ian Lloyd said on September 18, 2007 8:54 AM

Great to read this post, Andy. I’m always doing that breath-hold diving thing on hols and can manage to fin down to about 10m but it does give me the eebie jeebies a bit on the way back up! I’d love to give this place a go at some time. It’s been a long time since I last dived (scuba) - Koh Tao in Nov 2004, but never seem to find the time to do it these days :(

Jernej said on September 18, 2007 8:56 AM

one more thing…

If you want to combine scuba and freediving you could try diving oldstyle without a BCD and just a backplate to hold the tank in place (see underwater scenes in James Bond - Thunderball).
I don’t do this very often as it requires careful weight balancing (you wouldn’t imagine how much of difference simply changing to a different tank makes) but it’s a whole lot more fun.
On the first dive with an unfamiliar setup I usually go down slightly overweight, then at about 10m I pass the extra weights over to my (patient) buddy (what are brother for anyway?).

The thing you need to be careful are the final 5m as your neutral balance at depth and on the surface are very different (even more so with a 5-7mm wetsuit) so it helps if there’s something to hold on to (wall, rope, rocks etc.) to slow your ascent.

Other than that you shouldn’t have any problems. You will probably guzzle a bit more air as all your buoyancy compensation is done through breathing but on the other hand you’re dealing with a lot less drag.

Try it, it almost feels like freediving ;)

Rob said on September 19, 2007 8:46 PM

That video Jernej put up is amazing!
I have often done this in a very very armature way when on holiday. There is something about going down really deep where the water is really cold.
Although I’m not a fan of coming back up, when the last meter seems to go on for ever!
I think if I tried to hold my breath now I could probably only do a minute max!

Mark Lloyd said on October 2, 2007 5:52 AM

I have recently just got into snorkeling and hoping to move to scuba eventually.

hopefullly you can clear something up for me, can asthmatics do scuba diving?

i did a bit of a google search and it was inconclusive :)

hopefully i am able to, snorkeling thusfar has been awesome and the scuba stuff i have read/seen is just awesome. :)