FROGDIVER NOTES

An old buddy (yes, I have a few older friends) commented on how I needed to “personalize” my site. “Say what you think,” he told me. The last time I did that it took years to live it down. But it is a different world now, people want to hear the, “real story”, or so he told me. The idea is seductive. I could have an effect on the diving industry, sure. Well it most likely will not hurt anyone, just like the last time. So there, you have it!

QUESTION:

What happens when I flood my rebreather counterlung?

ANSWER:

1. You loose a lot of buoyancy, fast.
2. It may get harder to inhale or exhale.
3. Caustic water may appear at the inhale side of the mouthpiece.
4. Partial flooding may produce noise, “bubbling” on exhale/inhale or both.
5. A novice rebreather diver will become aware that something is not right.

WHAT TO DO:

1. If you have a “redundant” back-up open circuit system to use? Use it now.
2. If possible, start a “controlled” ascent. Once on the surface, examine your unit and find out what happened. Make this a learning experience.

FROGDIVERS: When the FROG counterlung floods the unit becomes a “hybrid”. The location of the demand regulator and the exhaust valve in the mouthpiece allow the user to breathe the dilute gas in an open circuit mode, if the user maintains a head up position. This uses up the dilute gas fast, but gives the user more time to make an “orderly” change to the redundant back-up open circuit system.

Why did I not patent this? I want other manufacturers to copy this feature, be my guest, help a diver in a challenging situation.

QUESTION:

Why is the FROG scrubber inside the counterlung?

ANSWER:

The Carbon dioxide reduction chemicals work best at a stable temperature, 80 to 100 degrees Fahrenheit. Placing the scrubber canister/cartridge inside the counter lung protects it from the cold water. Most of the FROG breathing path is made of materials that have a low Delta T. The manifold is epoxy, the counterlung is Bioxlex, the breathing hoses are rubber and the mouthpiece is Delran. Dr Albert Behnke, Dr John P. Jones and Charles E Michielsen patented the “scrubber in the breathing bag” in 1985. It was based on a Behnke/Frye patent of 1943 and later modified in a James C. Fletcher NASA patent in 1979. Dr Behnke, Jones and Michelson licensed the patent to me in 1990. I have used the technology since then. The concept is simple. Surround the scrubber with warm moist breathing gas to stabilize the chemical temperature. Heat is conserved in the breathing loop. The chemical reaction is optimized and the user is provided warm moist breathing gas. The FROG scrubber temperature varies only five degrees Fahrenheit due to water temperatures from 80 down to 35 degrees Fahrenheit. Cold water has little effect on the FROG scrubber performance. There you have it.

 

QUESTION:

What is the function of the pressure relief valve on a SCR/CCR?

ANSWER:

The breathing loop is a reservoir of gas that has to be released when you ascend in the water. Yes you could just exhale out through the nose and dump the gas. In fact many of us plugged the exhaust valves, “on the old systems” to keep them from leaking and used the nose to relieve the pressure. It was simple and not too annoying. In most units the location of the system exhaust valve causes a blow up effect on ascent that causes overpressure in the mouthpiece and “puffed” cheeks. The FROG has two pressure relief valves in the system. One is on the manifold and one is in the mouthpiece. The manifold valve is set high to activate only if the mouthpiece is closed and you make an ascent, such as with a “bail-out” condition. The mouthpiece valve is set by the user to relieve when a small amount of overpressure is present in the breathing loop. This prevents “blow-up” and allows better buoyancy control on ascent. There you have it.

 

QUESTION:

How can I tell if my buddy is breathing normal when using a rebreather?

ANSWER:

With a semi and closed rebreather there will be no regulator hiss on inhale and no bubbles for every exhale. This is the first challenge for new rebreather instructors. How do you evaluate the student breathing? There are several subtle indicators.
1. The new diver will have, puffy cheeks, except when inhaling.
2. The student’s chest will move with the breathing cycle.
3. Exposed counterlungs will swell or retract with each breath.
4. Have the student do a “fin pivot” and clear the facemask to evaluate the students breathing rhythm.
5. Watch their face, check for a relaxed expression.

COMMENT:

Watch people around you in their everyday activities topside. They are rebreathing. We all do it everyday all the time. We give signals when we are under stress, labored or rapid breathing indicates changed states. Being aware of your students or buddies emotional or physical state underwater requires attention to details. Everyone is different, learn their unique behavior. Sociologist calls it “symbolic Interaction”. It tales several symbols to communicate effectively. Stay close to your dive partner. Share and enjoy the total experience.

 

QUESTION:

What I don’t like about rebreathers.

ANSWER:

Cleaning them. A closed breathing system, be it semi or full, is the perfect environment for pathogen maintenance. Bacteria and viruses that are introduced into the system can remain viable for many days. In the old days we called it “spit swapping”. Cleaning the breathing loop was a major part of Military and Commercial training programs. Navy Chiefs made it a point of personal offence if they found a dirty breathing loop in your dive equipment locker. Dirty breathing loops cause cross communication of infects diseases. Military and Commercial dive operations see it as a threat to efficient operations. For the sport diver, using a dirty breathing loop will send you home with something you did not barging for.

SOLUTION:

For Most rebreathers it will take at least thirty minutes to an hour to clean the breathing loop. Do it as soon as possible after the last dive of the day and any time more than one person uses a single unit. Multiple users are the most hazardous condition as the time to clean takes away from the time to use the unit. This leads to incomplete cleaning. For the FROG the cleaning time is reduced by the use of disposables. A disposable pre pack scrubber and counterlung liner makes the cleaning of the FROG a five-minute task.

COMMENT:

The absorbent material, Sodasorb or Sofnolime, is not a biological or viral anti agent. It will not kill the pathogens and offers no protection from pathogen build up. Thorough cleaning is the only solution to the problem.

 

QUESTION:

Is buddy diving with a rebreather different than with open circuit diving?

ANSWER:

I stopped using the term “Buddy” to define my dive “partner” many years ago. A dive partner is someone that shares your dive with you. In order to share your dive the partner has to be competent in the task. Mixing rebreather divers and open circuit divers in “buddy” teams is not safe unless they are both competent in rebreathers and open circuit.

COMMENT:

In the old days, we had a saying about “buddy divers”. Same ocean same day and stay clear of me underwater. Over the years I learned the value of having a dive partner. I have made many “working” solo dives. I prefer to have a dive partner, like a life partner, to share the experience with. It is part of the joy of diving.

 

Every diver is a sea-creature in process. I am still learning. Too old to make millions, too young to quit trying; join me in sharing the adventure.

The FROGDIVER

froggy@frogdiver.com