Caribe Diving, rebreathers, inspiration, evolution

Rebreathers have been around for some time and in the past 10 years the technology has developed in
leaps and bounds. Today we have a number of rebreather units that are reliable and safe to use for
recreational as well as technical and extreme dives.

Rebreathers are dangerous machines and requires specific training for each unit. To be a safe rebreather
diver, it is imperative that the diver understands how the unit works. The safety of the unit comes with the skill
and knowledge of the diver.

How does it work? Imagine you are breathing in and out of a plastic bag. If you can find a way of
replenishing the oxygen that you metabolize, and removing the carbon dioxide your body produces, then you
actually have a rebreather. All rebreathers work on a similar concept, replenishing the O2 and removing the
CO2.

Which rebreather should you buy? The answer to this question will vary, depending on who you would ask.
But here are a few pointer questions you should ask:

1) How reliable is the unit? If the manufacturer invests time and money into extensive testing and updating
of his product and it has a proven track record of reliability, then it deserves to be put on your short list. Does
it have CE approval? Has the WOB (Work of Breathing) been tested? Did the manufacturer do stress and
depth tests on the components.

2) Under what conditions should I abandon the unit and go to open circuit? This is a very controversial
subject in the rebreather world and many instructors maintain the view that at the slightest sign of something
being wrong you should abandon the rebreather, or at least go on open circuit until the problem is resolved,
then return to the rebreather. This may be true for many rebreathers on the market, but if you intend to do
some serious diving on your rebreather you want a unit that will give you many options to recover from a real
or perceived problem.

3) You also want a rebreather that allows you flexibility in the way it is used. An important feature of safe
diving is to develop a regimen of procedures for yourself. Procedures that you can easily remember and
develop to become almost "muscle memory".

Obviously there are many questions that you should also consider if you are in the market for a rebreather,
but the above are just a few of the most critical.

A rebreather that I found that is extremely flexible and provides me with recovery options for almost any kind
of failure imaginable, is the Inspiration rebreather, and its newest brother the Evolution rebreather,
developed by Ambient Pressure Diving in the UK. The distributor in the USA is Silent Diving Systems.

Suppose the system develops a leak, you can drain the water from the breathing loop. Even if the water leak
is in the cannister where the scrubber is, you can force the water back to the drainage point and drain it off.
No need to abandon the rebreather.

If the electronics fail, you can follow simple semi-closing procedures where you can drive the unit back to the
surface and even do decompression stops on it without having to bale-out to open circuit.

If the scrubber fails, for whatever reason, you can semi-close the unit and return to the surface, including
doing decompression stops.

If the tank valves fail and you loose all on-board gas, you can plug in off-board tanks by using a simple
inflator hose connection and complete the dive as if nothing occurred.

If you are unsure about the purity and or reliability of the gas in the breathing loop, you can always take a
"sanity" breath, directly from the rebreather, without baling out to open circuit. You can do this instantly and
effortlessly.

The only reason you would need to totally abandon the rebreather is when the scrubber cannister is flooding
faster than what you can drain it. This is called a catastrophic flooding.

Considering the points of failure and the possibilities to recover from the potential failures, it becomes clear
that it is possible to recover from more failures on the Inspiration Rebreather than what it is to recover from
failures on Open Circuit dive gear.