Dive Office

Rebreather Technology arrives in the UM/RSMAS DSO

Early this April, I participated in a rebreather training workshop hosted by the University of Hawaii. The training was conducted over 7 days and had classroom discussions and open water components that included 8 rebreather dives.

For those of you who have no idea what a rebreather is, it’s a piece of equipment that captures a divers exhaled bubbles, puts this captured gas through a chemical absorbent that takes out the CO2, and analyzes it to makes sure that the gas returning to the diver is what the diver has programmed into the computer. If the gas is ok during the analysis, the rebreather leaves the gas as is. If the gas is not what it is supposed to be, the rebreather injects gases into the mixture so that the diver receives the correct gas.

As I prepared for the course, I have to admit, I was very skeptical about the technology as I had heard and read about many accidents that have occurred using rebreathers. I am sure many of you have heard or read similar reports and have heard me tell you I wasn’t so sure about rebreathers. So prior to the training I did a more thorough review of the accident reports and started to see that most of the problems divers had on rebreathers occurred by the diver prepping or setting up the unit improperly, failing to understand information given to them by/about the rebreather, or failing to take proper “bailout” should something go wrong with the rebreather. This made feel better as these were correctable problems or reasons for why people had problems.

I also did the studying required for the course. As my familiarity and understanding of the details increased, I continued to feel a little more comfortable. But I still had some trepidation regarding the technology. It was not until I got my hands on the equipment in the classroom and went through the functions and features with it sitting in front of me that I started to feel comfortable.

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My comfort level grew even more when we first dove using the rebreathers in the pool. This session was a 2 hour dive where we got used to our buoyancy, the different components, and the general feel of rebreather diving. All the students in the course (all DSO’s) became comfortable pretty quickly using the rebreathers in the water, so we planned some open water diving for the next day.

The open water dives went pretty well. I felt as if I was a new diver in the sense that I was re-learning how to dive. One thing new rebreather divers must recognize is that many of the skills they have developed for “regular SCUBA” don’t apply to rebreathers, especially the buoyancy. On regular SCUBA, you try to achieve a neutral buoyancy level where you can adjust your buoyancy by controlling your breathing. This doesn’t work so well on rebreathers as I learned many times on the first couple of dives. Every time I started to descend a little I caught myself inhaling to try to give me some positive buoyancy, which didn’t work and I’d crash into the sandy bottom. The course instructors had seen this before and chose the correct dive site for the “newbie”.

All the students progressed at a satisfactory pace and we did 2 dives each day (8 dives total) for the remainder of the course, with the highlight being a deeper dive (120 ft.) on a wreck called the Sea Tiger.

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On the Sea Tiger the water was warm and clear. The dive profile allowed us to spend 35 minutes on the main deck then do a multi-level ascent exploring the various decks and nooks and crannies. This is also where I began to notice the difference the lack of bubbles had on the marine life.

On our ascent to the top of the wheelhouse at about 80 ft., we came upon a resting Green Sea Turtle. We all floated a fair distance off, not wanting to scare it. We looked for several seconds then slowly crept closer. The turtle looked at us a couple of times with more curiosity than fear. We eventually all approached the turtle and then rested on the wheelhouse just behind and to the side of it. The turtle was unafraid and rested there while we all high-fived each other and mugged for camera time. It was a very nice way to cap off a great dive.

turtle

All in all the experience was positive and I now have a much better understanding of the technology. I am also in a much better position to oversee rebreather diving operations and encourage our divers to contact me if they have questions about applying this technology to their research.

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The course was coordinated by David Pence, UH DSO, and Peter Den Hann from NAUI as instructor trainers with Kevin Flannigan and Derek Smith of UH doing the instruction. The staff in itself was a comfort as I have known and respected these divers/DSO’s for a long time.

 

For more information on how UM scientists are using rebreathers, please refer to Dr. William Browne’s website.

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