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Tech Profile | Karl Shreeves

Joe Cocozza meets Karl Shreeves to discuss the state of tech diving today and the impact it is having on recreational diving


KWSslfOct13 09 optKarl Shreeves is a technical, cave and scientific diver, who works as a Development Executive and an Instructional Designer for PADI. He has participated in dive expeditions as a research diver and with NASA Extreme Environment Mission Operations has studied human spaceflight dynamics in an underwater habitat. Karl is also an excellent photographer.


 THE TERM ‘TECHNICAL DIVING’ came into existence in the early 1990s. It was used to define scuba diving that was outside what the mainstream training agencies (PADI, NAUI, BSAC)  were promoting and teaching. Tech diving became a catch-all term for divers who pushed the limits, whether doing deep decompression dives or long penetrations inside underwater caves.

Divers in New Jersey and the UK were doing wreck dives with hour-long deco hangs. Cave divers were exploring in the springs of North Florida and the jungles of Mexico. Divers were repurposing old military rebreather technology and experimenting with mixed gases for deeper, longer dives with accelerated decompression. It was a time of radical revolution in techniques, equipment and, ultimately, training protocols.

For most of the 1970s and 1980s, training agencies had been trying to grow the sport of scuba diving by making it a safe, family activity. So they pushed back against tech diving, declaring it outside the realm of ‘recreational’ diving. And the divide between recreational vs technical diving was formed.

There were many scuba instructors (myself included) who taught recreational scuba programs, but would frequently do multi-staged deco dives using double tanks and stage bottles for fun. We felt like parents who told their kids ‘don’t smoke’, but had a two-pack-a-day habit.

Another one of those instructors was my friend Karl Shreeves. Karl’s passion was cave diving, but he also worked for PADI as an Instructional Designer. He was instrumental in demystifying tech diving within the ranks of PADI and showing that with the proper training and equipment, it was not just crazy stuff – its equipment, protocols and methods could be brought into the mainstream. In 2000, PADI introduced its Technical Diving Program and brought its expertise in training to technical diving.

In the early days, there were radical changes almost every year in tech diving, but now we see the sport maturing and moving into a more stable growth phase. I talked with Karl Shreeves about today’s gentle evolution of the sport.


In the last 15 years youve been working at the forefront of bringing technical diving into the mainstream. So what would you say is the state of tech diving in 2014?

KS: I’m not seeing radical changes, but a more gentle evolution. While tech diving technologies continue to advance, and more divers get trained in tech diving, there’s a convergence and adoption of these technologies into recreational scuba.

So theres been a blurring of the lines between technical diving and recreational diving?

KS: Exactly. For example, today if you’re a closed-circuit rebreather (CCR) diver, you could be what we call an R-CCR (recreational rebreather) diver. This often becomes a pathway for a diver to go from recreational diving into technical diving. However, the diver does not have to progress to what has traditionally been classified as ‘technical diving’; the advances in technology greatly expand the adventures available to the recreational scuba diver.

What makes a recreational R-CCR different from a technical CCR?

KS: The R-CCR has to have functions that make it suitable for recreational diving. The functions are: easy to maintain; fully automatic; and having a distinct bail-out capability. Any recreational diving is no-stop, which means if there’s a problem the diver can make a safe assent to the surface. So, in summary, if you have a problem with the rebreather a warning light will flash, you will flip a switch and start breathing open-circuit. Then make a direct assent to the surface.

This is different from a technical rebreather. While a CCR might have the same features, it’s designed for a more sophisticated user. There’ll be situations when the diver can’t make a direct assent to the surface, for example if they have a long decompression obligation or are in the overhead environment of a cave. In the advent of an equipment failure of a CCR, the technical diver is trained to manually operate the rebreather. 

The technology of rebreathers is really coming together and there are some stellar recreational rebreathers on the market today, including the Hollis Explorer and the Poseidon Discovery.

How do the two PADI training courses for recreational and technical rebreathers work?

KS: The recreational rebreather user is diving a simpler unit, from an operational standpoint (though the unit has a more complex control system from an engineering standpoint), so the  course does not have to be nearly as extensive. It doesn’t have to cover topics such as decompression techniques and theory, for example. But the two courses do cover many of the same subjects. If you become a recreational rebreather diver and later decide you want to move up to be a technical rebreather diver, you get credit for what you already learned.

So you have taken a standard PADI continuing education approach to rebreather training?  

KS: First I must say, it’s an extensive course where you’re going to learn to dive the unit well. Also, CCR training is unit specific. However, the diver gets credit for prior learning and that’s one of the key things we’ve integrated into our instructional design. For example, if you trained as a PADI R-CCR diver on a specific unit, say a Hollis Explorer, and you want to learn how to dive on another R-CCR, such as a Poseidon Discovery, you don’t have to start over from scratch. You have already studied the theory, you just have to qualify on the new unit. 

It gets a little more complicated with CCR, because more and more people are becoming technical rebreather divers who’ve never done an open-circuit technical dive. Tech courses have to be more sophisticated in their approach. When you get into things like depth factors, oxygen toxicity and deco theory, it’s serious suff. The instructor can’t assume you have this technical knowledge.

In the way rebreathers are now both tech and rec, so sidemount diving is becoming a big thing within recreational diving. So is technical diving now enriching the dive opportunities for the average recreational diver?

KS: Well, advances in technical diving have contributed to recreational diving for a long time now. My favourite example is the alternate air source (octopus) that we all swim around with today. It was actually invented by cave divers as a way of sharing air inside a cave. Now it’s considered obsolete in cave diving, however it’s standard equipment in recreational diving. 

Advances in tech dive training are now filtering down to how we train recreational divers. For example, the Open Water course now takes into account that dive safety traces back to a diver’s initial training. We studied scuba accidents in which divers, considering the circumstances, should have died but didn’t and we looked at accidents where divers should have survived but perished. What we found is it usually goes back to lessons learned in basic training.

So in the updated PADI Open Water course, we’ve put greater emphasis on teaching the diver how to think and to develop habits that will help them when they encounter problems in the water. To ask themselves for example,‘How do I wear my gear at the surface?’ And think, ‘I want to be able to see underwater. I want to be able to breathe underwater. I don’t want to be over weighted.’ So in water too deep to stand, we help divers develop the habit of keeping their mask on and their regulator in their mouth. Rigged this way, the diver can respond to problems more easily. We’ve taken this approach to other aspects of the Open Water program including buoyancy, simple gas management strategies and simulated mini-dives.

The reason we do all this training is so we can have great underwater experiences. What potential dives are there out there for tech divers?

KS: There’s no question the opportunities available to technical divers are expanding.  Nitrox is common everywhere. More dive centres are catering to rebreather divers – they have CO2 absorbent, pure oxygen,
trimix and CCR cylinders.  

A lot of old-school tech divers come from a culture of diving in cold, dark conditions. But in fact, I think the best place to a dive a CCR is in the tropics. It’s great to jump in the water, do a long dive and see an entire reef or shipwreck. All this and never worry about going into decompression. You get a different experience. This is why I got all this hardware!



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