Three Golden Rules

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Short and simple:

Use a checklist to prepare your rebreather.

Complete a five minute pre-breathe with a blocked nose while safely seated and paying attention.

Never dive a rebreather with a known fault.

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Canadian Association for Underwater Science

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12755429_10156531437700244_2095834210_oThe Canadian Association for Underwater Science annual Scientific Diving Symposium was hosted in St. John’s Newfoundland this year with perfect timing. Our team put in a good performance. Neal Pollock gave a seminar on Physical Fitness for Scientific Diving. Rick Stanley and Phil Short gave an excellent talk on our project and surprised us will a 3-minute video clip edited by our extremely talented cameraman Cecil Johnson. He stayed up to the wee hours of the morning to prep a fabulous preview of our project. I ended the day with the Keynote talk on Operational Dive Safety. After a meal at Yellow Belly’s in St. John’s and some rousing conversation I had to rush off to the airport to catch an 11:15 pm flight. Freezing rain was on the way and it was advised to try to get out to Halifax instead of awaiting my morning flight. I would not be too worried about flight delays, except I have to get to Chicago to the Our World Underwater Dive Show to host the Friday night Film Festival and give some presentations on our project. No rest for the weary. Sleeping on the airport bench, awaiting my dawn departure from Halifax now, I am officially tired.

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Mixing Rebreathers with Open Circuit

By | All Posts, Cave Diving, Rebreather Diving, Women Underwater | No Comments

Madison Blue SpringWhen CCR divers and open circuit (OC) divers dive together, they are referred to as a mixed team. OC divers are often shy about asking a CCR diver how procedures may differ so it is up to you to ensure that gas management and emergency procedures are clear prior to entering the water.

1. Orientation

Show how the rebreather is donned and how it can be removed. Demonstrate how the wing is inflated and, if it is attached to an onboard cylinder, discuss how this limited supply could be easily exhausted during a rescue. Determine whether oral inflation of the wing by the buddy is possible. Discuss various warning lights, especially those that indicate life-threatening oxygen levels and discuss how developing problems can be recognized. Describe the significance of a vibrating mouthpiece, if applicable. Describe how and when it might be necessary to close the loop and why preventing a loop flood is critical for buoyancy.

2. Gas Planning

Inquire about the air consumption rate of the OC diver and plan appropriate gas volumes to ensure safe ascent using your bailout gas. Select bailout gas that is compatible with the OC diver’s decompression plans and plan decompression gases to accommodate all emergency scenarios.

3. Complete a Safety Drill

Describe what to look for during the bubble check, then rehearse gas-sharing scenarios prior to entering the cave. Determine whether sharing a long hose or passing off a bailout bottle will be a better decision.


If CCR divers strive to maintain a high level of conservatism and independence with their bailout gas, then safety and flexibility are benefited. Self-rescue is assured and buddy rescue of a CCR or OC diver is also probable. The goal of the orientation is not to teach the OC diver how to run a rebreather, only how to share gas and handle emergencies that may occur.

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Advice to CCR Photographers and Videographers

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Rebreathers are ideal for capturing incredible animal action. When you slide through the water column without making bubbles, suddenly you are a part of the environment, not simply an invader making noise and a curtain of gas. That being said, we use a different part of our mind to process creative thought than the part of the brain necessary for intellectual processing of rebreather skills. Videography and photography create an enormous task load and one that robs you of a sense of time. It takes a lot of skill and patience to force your mind to depart from the creative aspects of image-making and stay on top of monitoring your rebreather. I often shoot video and photos using my rebreather, but I am keenly aware that I have to stay on top of it and I advise my models to be extra vigilant with watching our time too.

Additionally, our buoyancy skills are hampered slightly with a rebreather. If you are a gas-miser, then your buoyancy skills will not be as fine-tuned as they are on open circuit scuba. You will need to monitor your onboard diluent and oxygen closely and allow for use of greater volumes. Conservation of the environment is critical and therefore, you should use a camera and viewfinder combination that allows you to look over the unit rather then through a small window, stuck against your mask.

Some features that help an underwater image-maker are:

1. HUD – A heads up display is critical. More importantly, it should be one that is capable of showing “exact PO2” and not just whether the diver is within range of his/her selected PO2. In my opinion, those types of HUDs do not protect the diver from making an inappropriate choice and not realizing their mistake. They also do not catch the diver who has forgotten to raise their set point at depth.

2. NERD – A new form of HUD, the NERD was created by Shearwater Research to show all your handset information in a small view find placed against your mask.

3. Some “Auto Set Point” features on some rigs will help ratchet up the set point as the diver descends, preventing you from slipping back to a lower partial pressure as oxygen is metabolized, but these are only appropriate for direct descents and not necessarily for slow or saw-toothed descents.

4. Vibrating Alarms – The Hammerhead-style rebreathers and some others such as the Sentinel, include a mouthpiece that vibrates in a life threatening situation. A vibrating alarm is nearly impossible to ignore and is far superior to simple audio alarms which may or may not be heard through a hood. Having also owned rebreather with simple audio alarms, I can tell you there is a big difference. Hoods impair hearing and older divers lose their ability to hear high frequencies, especially after a lifetime of listening to bubbles roar past their ears. Easily fifty percent of my diving colleagues cannot hear the beeps on their wrist computers.

So, despite the opportunities for animal interaction that rebreathers may present, ensure that you are making the right choice to use one for a particular dive mission. It all comes down to risk assessment. If you need every bit of your mind to run your camera well, then leave the breather behind. Perhaps that is why I still love to keep my free-diving skills up to snuff!

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Planning for Safety on Expeditions

By | All Posts, Sedna Expedition, Underwater Photo and Video, We Are Water, Women Underwater | No Comments

Nobody ever had real practice for something that has never been done before. How did Neil Armstrong practice how to walk on the moon? Individually and as a team, it can be challenging to develop an operational safety plan when you don’t know all the factors you will encounter. On our Proof of Concept Expedition, we had a lot to learn.

We spent many hours on Skype and email, but on our project, we were working together as a team for the first time. We hired an expedition support organization Arctic Kingdom which assisted with trip logistics, outfitting and hiring the charter vessel MV Cape Race. Cape Race had experience in the Arctic but had never supported a snorkeling and diving project before. A compressor, tanks, weights and Divemasters were installed on the Cape Race, but we still had to develop a safety document that would address everyone’s concerns, keep us within a tolerable risk envelope and would satisfy all the various insurers who also had a stake in creating a safe expedition.

Before I signed on to Sedna Project, I told Expedition Leader Susan Eaton that I was interested in developing the operational plan that would include how individuals prepared themselves for the expedition and how operations would occur on the boat. I developed a clear chain of command so that the Expedition Leader, Team Physician and Boat Captain could feel that they had the opportunity for veto if specific activities made them uncomfortable. I outlined a way for divers and snorkelers to accept personal responsibility and participate in planning and operations in a way that empowered them to take command, and also cancel or abort a dive if they felt they were over their heads.

On the first night of team building exercises in Nain, Assistant Expedition Leader Emily Dowding Smith asked us all to share our deepest fears about the project. She gave us each seven minutes to write down our thoughts and prepare to present them to the group. In the course of seven minutes, I counted all the dear friends and colleagues of mine who did not come home from expeditions. I recalled their smiling faces before the projects that were supposed to actualize their life dreams and I recalled writing letters to family, giving eulogies and going to far too many funerals. When the time came to present my fears I broke down into tears. Barely able to get the words out, my dear teammates offered for me to take a break, but through the pain, I knew this was the time to tell them that they were very special to me and that I wanted to get everyone home healthy above all other goals.

I am incredibly grateful to my teammates for their understanding and for using that empathy to conduct a smooth and safe operation every day. We gelled as team and we grew to be very effective together. We took turns being Dive Safety Officers, Deck Bosses and Deck Hands. We took every role with utmost seriousness even if that role was simply being in charge of safely loading a Zodiac or helping to dress another diver. I am incredibly proud of the focus on detail and concentration that everyone brought to each operation.

We achieved things that had never been done before and safely brought new challenges into our operations each day. Snorkeling on a relay in the middle of the Davis Strait with 9000 feet of water beneath us, I knew we could check off one big accomplishment. We are a great team.

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Buyer’s Guide to Rebreathers

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A Quick Guide to Buying a Rebreather CavernEntryJEH5745l

I’ve written many articles on this blog about how to shop for a rebreather, but given the numerous inquiries I have had recently, perhaps a reprise of information is warranted. The bottom line is that  the last decade of statistics shows us that the actual equipment brand does not seem to be a factor in accidents. Best available stats show us that there are no more accidents on one particular brand than another based on ratios of units sold. The same appears to be true when we look at manual versus electronic units. That means, the most important decision you can make is not “which” rebreather you buy, but rather how you use it.

Four simple actions should help you prevent 90 percent of the accidents:

1. Use a checklist every time you dive.

2. Do a proper, relaxed and complete pre-breathe for five minutes with your nose blocked.

3. Don’t jump in the water unless all systems are working perfectly.

4. Replace your oxygen cells proactively every year.

Beyond that, several factors may influence a purchase decision:

1. Third-party tests for work of breathing, oxygen tracking, canister duration and other factors. Ask the manufacturer for those and for details on their CE or equivalent testing.

2. Portability (do you travel on planes with it and will it fit in the baggage weight constraints?)

3. Availability of instruction from a trusted, experienced and current instructor

4. Local support and role modeling from dive partners or other experienced locals on a particular unit

5. Availability of support and service (where does it ship to for service? are they prompt and thorough? any complaints?)

6. Stability of the manufacturing company. Any issues?

7. Alarm systems – visual?, audio?, tactile? How much do you want?

8. Other features such as “auto on,” style of electronics, redundancy, battery type and charing or replacement, etc. Make a spreadsheet comparing features.

9. Budget

10. Ability to self-service basic needs

11. Availability of consumables (style of scrubber and batteries)

Its a tough decision and nearly everyone you ask for an opinion will have a strong one. They just bought the equivalent of a car and will likely ooze with confidence about their buying decision. You have to be pragmatic and analytical. A try-dive experience will only help you fall in love with a harness. A comparison of cosmetics will only help you decide whether you will look cool. Take time to compare features and research the unit on your own before jumping into one of the biggest purchase decisions of your life. Finally, make a pledge to yourself and your family that you will abide by the four Golden Rules above and make sure all your diving friends do as well.