Silent Diving

During the DEMA show we met a diving legend and strong scholarship supporter, Jeff Bozanic, he has hosted scholars for many years now and for the past four years teaching them how to dive closed circuit rebreathers (CCR). But we were all quite surprised when Jeff asked what we were doing the following week and offered to host us for a rebreather course the day after DEMA! Well we couldn’t say no to the course as it was something we all wanted to do! So after a busy week with little sleep in Las Vegas we arrived at Jeff’s house in Huntington Beach, LA and got stuck straight into the course. The other scholars warned us that Jeff has a reputation for packing as much as possible into every day and this course was no exception.

We actually arrived on Sunday the 26th October which happened to be Jeff’s Birthday and celebrated with an absolute feast of Indian food and his birthday carrot cake, with the leftovers becoming our stable diet for the week! The Bozanic family are very used to hosting scholars and were soon felt part of the family with his wife Rebekah and the three young children who hang out to play with the scholars every year. Also staying at the Bozanic residence was Barry and Celia Coleman, a South African couple that have been diving CCR for many years now. They have been involved with the development of the Poseidon Cis-Lunare Mk-VI Discovery rebreather – the unit that we got to test dive in Sweden during August. They had been living in Sweden for the past two years working on this system and especially a new training agency – RAID (rebreather association of international divers) that has the theory and exams over the internet. Hence we were soon some of the first students enrolled for RAID and started the course that evening.

For the next couple days we worked along on the RAID course and did some additional theory with Jeff. Jeff is very highly regraded in the rebreather world, pushing limits in deep caves and oceans. A well educated but very modest guy for having two PhDs and a bunch of incedible acheivements, he authored the book ‘Mastering Rebreathers’ and we now have a copy that is to be passed along from scholar to scholar. With short notice to arrange rebreathers for hire, we were lucky that Xtreme Scuba supplied us with some for a discounted price. We all used systems from Ambient Pressure , Jamie used the Inspiration Vision, Eline used the Evolution and I used the Inspiration Classic. We also has another diver on the course with us – Magne Tessem from Norway, he is an engineer working on a new integrated bail out mouthpiece/regulator for the Optima rebreathers. The four of had good fun sitting through Jeff’s lectures and a day in Jeff’s pool learning how to dive the units. Along for the course was one of Jeff’s friends and a CCR instructor in training, Ian Martin.

The following three days were spent diving from the Psalty V , a very nice boat with room for the seven of us divers to eat sleep and dive around Catalina Island. Also along on this course was another of Jeff’s friends, Elaine Jobin a local award wining photographer, she came along for some nice diving and to write a story and trip log for the three of us and get some great photos. Please check her website for more photos and a story of the trip

Diving rebreathers is very different and it was quite difficult to use these units for the first time. Rebreathers differ from SCUBA due to the fact that it recycles the air the diver breathes by removing carbon dioxide via a chemical ‘scrubber’ and periodically replacing the oxygen that the diver metabolizes. When used properly it can offer vast benefits in decompression obligation and gas consumption. The CCRs have a fully closed breathing loop, complete with a suite of sensors that monitor the oxygen levels inside the loop. If the controller detects low levels of oxygen within the loop, a solenoid will fire, injecting oxygen meaning that the diver allows the computer to control the partial pressure of oxygen. However, we would be learning to ‘fly’ the unit manually, by controlling our own partial pressure of oxygen in the breathing loop. Keeping the P02 at a giving set point takes a bit of practice, especially when you are concentrating on keeping your buoyancy, this is also completely different, as you cannot change depth by breathing in or out! We also had to do drills with the instructor such as changing depths, bail out procedures, mask off drills and out of air simulations. We also had to demonstrate the best way to deal with the multitude of potentially life threatening problems that can occur underwater. It was needless to say we learnt a lot on this course and definitely made us better divers all round and increased my knowledge on diving physics and theories.

After our seven training dives down to a max of 30 m, we were then ready to have some more fun on these units and gain a greater appreciation for ‘silent diving’. We took our video cameras down for some beautiful diving through the kelp forests of Catalina. We were getting close to fish species that would normally swim straight away from divers. Our last dive was especially good as the sun was starting to set we didn’t worry about filming and cruised around to 30 m, it was dead silent and so much more peaceful than diving open circuit. These units have so much potential and they are only going to grow in popularity as new models are coming out every year and technology and these new developments may change the face of diving completely. With bottoms times that can exceed 4 hrs without a fill and with greatly reduced or zero nitrogen loading at shallow depths, while witnessing the natural behaviours of fish, this is definitely something that I will pursue in the future! Thanks to Jeff Bozanic, Ian Martin, Elaine Jobin and Garry Jackson the boat skipper for an awesome course!