Wannabe a tec deep diver ?
Is PADI’s venture into teaching “technical” diving a piece of window-dressing to grow its market further, or a serious attempt to come to terms with the demand for deeper, safer deco-stop diving? In his continued quest to earn every diving qualification available, Chris Boardman heads for the Red Sea to find out
Like slow-motion sky-divers, our four-man team descended past the recreational scuba crowd enjoying the reef. Another minute and the Chimney came into view, a distinctive crack in the seabed that drops to more than 100m and signifies the start of a wonderful dive.
As we continued our descent, we passed through the first of a series of arches formed by ancient corals bridging the narrow gap. It was beautifully quiet and the shafts of light coming down through the shallows created an almost religious effect. Ten days of hard work were made worthwhile in an instant.
How many of you, while diving with a single cylinder, have dipped below the “recreational limit” or let your computer slip into decompression mode? Me too. As I have become rather fond of living, still want to explore the depths and am on a mission to avoid real work, I decided to check out PADI’s venture into technical diving in Thailand.
Thailand has a history of technical training, but until now has taught primarily TDI courses. Now it offers the relatively new PADI/DSAT Tec Deep Diver course as well. I wanted to look principally at PADI’s offering,
A classroom theory session was followed by equipment set-up. DSAT (Diving Science and Technology, PADI’s technical arm) encourages a standardised approach to equipment configuration. So it recommends use of a simple webbing harness, metal back-plate and wing-style BC. That’s my preferred system anyway, even for single-cylinder diving.
If I was expecting a gentle introduction to tec diving, I was out of luck. The skills circuit I did on each of three dives stretched my mental limits. It started from when I stood up wearing half a ton of equipment and jumped off the dive-boat. Over the next few days, it never ceased to amaze me when I actually bobbed back up to the surface.
The challenging exercises included gas shut-down procedures, towing an unresponsive diver at depth and buoyancy control skills, such as removing and replacing deco cylinders midwater with no mask.
My favourite portion of each dive was the “free time for practice” section. I was introduced to exercises that are crucial to the development of a technical diver, such as unannounced mask removals and simulated free-flows (finger appearing on a regulator purge button). This was to be a recurring theme over the next two weeks. At one point, I was hovering at 6m without a mask and deploying my SMB when the stage cylinder from which I was breathing free-flowed. Using a “spare” hand, I shut the cylinder down and switched to the other, leaner mix. Surprisingly, this subsequently free-flowed too.
The idea was to see how I prioritised tasks under stress, as it was physically impossible to keep doing everything. It was… intense.
Much of technical diving is in the planning. After breakfast i was guided through a planning session using a variety of tables and DSAT’s excellent data-carrying slate. The emphasis of the day’s two dives, to 25 and 20m, was to implement the schedules we had created.
Dive one went smoothly, with only two “free-flows” and one “lost” mask. Once I had stowed the SMB, we dropped straight back down to a 5m sandy patch for another supplementary skill; kit removal and replacement, a little trickier with tec kit, but OK if you take your time.
During dive two I had to deploy the SMB from the first simulated deco stop at 15m, and in the same 1min stop make a gas switch. This was further complicated when we found ourselves under a dive boat, at which point my instructor simulated switching to the wrong decompression mix for the depth.
I had become so distracted by trying to get the SMB ready and getting out from under the boat, it was about six seconds before I noticed. Bad move. This was another lesson in prioritisation. Supervising a team-mate’s gas switch should have been number one, and the SMB could have waited. I was task-overloaded, refused to accept it and, as a result, a team-member could have died.
That evening I sat the first of two exams, consisting of 100 questions. I was then given the basic information with which to plan the next day’s dive. It had been a 15-hour day – I finished at 11pm.
The focus was again on strict implementation of schedules. Deco-stop depths had to be controlled to within 40 centimetres.
This was a simulated deco dive, so the stops were short and task-loading was at a level normally reserved for training purposes only.
No real decompression dive would ever be planned this way. First, however, we had 15 minutes of bottom time, skills to practise and, as usual, most of them were without a mask.
Even with such tight time-windows, I somehow managed to keep to the schedule. That made me happy but I have to admit to feeling pretty stressed after the dive.
I wasn’t looking forward to the next one, either. There were fewer skills to do but there would be another intense ascent with multiple gas-switches, reel-deployment and a simulated primary- wing failure thrown in at 9m for good measure to make this another hard day on the edge.
fully-fledged decompression dive to 40m was followed by another simulated to 25m. My instructor had decided to let up on the surprises for now. He told me he was happy with my abilities under stress and that we would focus on precise execution of the dive plan.
The first dive went smoothly. We didn’t deviate more than 20 seconds from the plan and depth was controlled to within 30cm throughout. This was the first dive on which I felt I hadn’t relied on an element of luck.
The second dive to 30m was considerably shorter, designed to practise ascent procedures. No problems, and I ended the day with a growing sense of self-confidence.
I was learning to implement the mass of small tips and techniques I had acquired over the preceding days, such as preparing gas-switches before arriving at the stop depth and launching the SMB at the end of a stop in case it pulled me above my planned ceiling.
We were approaching the course limit of 50m. All the dives would now be decompression, and there would be only one each day. Today’s, at Ras Mohammed National Park, was an accelerated-deco dive using nitrox 40 and 60.
At the bottom I noticed the presence of narcosis for the first time. However, by now I was able to perform two shut-down drills and a five-minute surface air consumption (SAC) rate check, while monitoring depth, time and cylinder pressure accurately.
A technique I employed for the first time was a controlled buoyant ascent, inflating a wing to start off and then dumping air as normal, allowing the equipment to do as much of the work as possible.
Though taboo in normal recreational diving, this is often desirable in technical diving. From a state of neutral buoyancy a diver might otherwise have to swim a lot of gear a considerable distance up before enough air expanded in the wing to create the required lift, and during any extra time spent at depth, nitrogen is of course still being absorbed.
This technique is possible because of the smaller pressure changes encountered in deep water. It illustrated for me why specialist training is so important when venturing just those few metres deeper than normal recreational depths. Try this kind of dive without being in control, and you could end up in hospital or worse.
Today’s dive was to the full 50m. No new skills were being introduced now, just practice. Far more confident in my new abilities now, even the possibility of Leigh springing surprises was no longer a cause for nerves, as I knew I could deal with them. I was starting to enjoy myself, and became aware for the first time on the course that there were actually fish down there.
By now I was doing all the planning and “leading” the dives under careful supervision.
I took care of the tracking of oxygen exposure and gas-planning manually, though the dive profiles were calculated using the popular V-Planner software.
The most relaxed day yet, and even at 50m the narcosis effect was minimal. I performed two complete shut-down drills and one SAC check before signalling the team one minute to ascent and preparing the nitrox 40 cylinder for arrival at 30m.
As we cruised along, my instructor tapped me on the shoulder and indicated that I should look below.
I gazed into the depths of the canyon before looking back up at him. He was holding up a slate on which was written: “Bottom 100 metres. Trimix course starts next week, mate!” Suggestive selling at it’s best, I thought.
The most daunting task of all still awaited, the “snorkel test”, complete with blacked-out mask, which generally takes place in the pub next to the school. The rest I’ll let you discover for yourself.
PADI/DSAT Tec Deep Diver was a far more comprehensive course than I had anticipated. It isn’t for everyone and shouldn’t be seen as a logical progression in diver training. It’s more like trying a different sport, because the commitment, effort and money involved are significant.
The manual has that comfortable and effective PADI style, but so far as contents go, this is where PADI ends and DSAT starts. When reading my Open Water manual and discussing how to help a buddy in difficulty, I don’t recall leaving him to die as being an option. However, in the DSAT manual the phrase “better thee than me” indicates that in certain circumstances this is the guiding principle.
It doesn’t pull any punches. Indeed, the first chapter is spent trying to persuade the reader not to do the course! It gets progressively more demanding, too, taking a good 12 hours of study to absorb. Sad bloke that I am, I actually did a word count of my knowledge review answers and it came out at about 6500! So don’t be tempted to leave mastery of the manual until the last minute or you might find yourself in a classroom instead of a reef.
After about five days of the course the candidate becomes an Apprentice Tec Deep Diver, certified to dive to 40m using nitrox mixes up to 60 per cent O2 with full technical equipment and methodologies. Some people will welcome this potential break-point in the course, enabling them to split the training into manageable chunks, because at a recommended 10 days, only PADI’s pro courses can rival this one for length.
Acronym overload aside, I have a few criticisms of the manual and the course itself. A lot of learning time is spent on tracking long-term exposure to high ppO2s. I agree that tec divers need to know this stuff, but on this course they are unlikely to achieve the kind of run-times that would make this an issue. Perhaps a little less emphasis on calculating OTUs and a little more on human physiology would be better?
Second, as tec diving requires total self-sufficiency, it seems crazy that a redundant/back up mask is “recommended” and not mandatory. If you lose a mask, how do you make a controlled ascent and/or deco-stops?
Third, at no point is the student required to remove equipment under water. This seems strange, as it’s a skill thought valuable enough to teach as far back as your first Open Water course.
I was required to do all these things and far more. Supplementary exercises were designed to help the candidate deal with stress and stay focused when the only sensory input was feel – ideal for UK diving. They sound draconian, but gas was always available to anyone unable to complete a task.
At this level you should interview your instructor. Evidence of passing an exam is not sufficient; you need to see proof of experience and a good mentality, for some will surely slip through the net. A good instructor will welcome interrogation, as you will be displaying exactly the kind of attitude you need for such an undertaking.
This was a tremendously satisfying and challenging course. PADI’s move to embrace the less-than-simple world of deco-diving is commendable. Such is the diving fraternity’s faith in this mammoth organisation, it will undoubtedly boost the number of sub-30m divers out there.
DSAT has done PADI proud, and this was a view echoed by all the technical instructors I consulted from other agencies. It is not the de facto technical course, but with a few tweaks might well become so. We should expect to see amendments made and supplementary courses such as trimix bolted on soon.