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You're very welcome Pierre.
Now that you know that, here's a simple way to achieve the pressurization
in your pod. Attach a long air hose from an air tank to a scuba regulator so
that the regulator can hang right in your cockpit within reach.
Remove the mouthpiece from the regulator and purchase a reinforced (with a
stiffner that keeps it from collapsing) rubber or silicon tube that fits over
the plastic piece the vinyl mouthpiece formerly attached to. Full face scuba
masks have this tube and you can find it online or at your scuba shops
that sells full face scuba masks. Now attach your new tube that replaces
the mouthpiece to the regulator with a plastic tie wrap. It should slip on and
be very tight and made even tighter by the tie wrap. Now into the open end
of the new tube attach a pvc fitting and secure the two together either
with a hose clamp or tie wrap. The pvc fitting you installed should be an
adapter fitting that goes to a smaller size on its now open end. Make sure
however you adapt
this that the pvc fitting is threaded and will accept a standard scuba air
hose. So now you have your regulator adapted with a air supply hose going into
the regulator as you normally have it hooked up for scuba AND....a air hose
going into the mouthpiece where you would normally breath. The other end of this
air hose that goes into where the mouthpiece went, attaches to a thru the hull
fitting going into your battery pod. The reason for having the regulator in the
cockpit is so if it ever free flows you can clamp your fingers over the exhaust
ports of the regulator and stop the free flow. We divers have to do this all the
time regularly. But you can cut down on this by buying a scuba regulator with a
lever that varies the sensitivity of the regulator. Set it to the setting that
makes it the hardest to
breath thru and you will almost never have a freeflow and it will work just
fine for pressurizing your pod.
So now what happens is....the outside water pressure is trying to get into
the void of your battery pod. When the outside pressure builds up to the point
where it pushes against the diaphram behind the purge vavle button on the scuba
regulator (which is
where the water is trying to enter to get into your pod) and it will open
the diaphram in the regulator and air will be vented into the pod from
the scuba tank attached to your scuba regulator. Now when the air pressure
inside the pod reaches the same pressure as the outside water pressure, this
causes the diaphram in the scuba regulator to close and stop any more air from
venting into the battery pod. So you see as you go deeper it automatically
pressurizes it for you. Then when you accend, the air in the battery pod expands
and is expelled out of the scuba regulator's exhaust ports. Neat huh? and
simple. All you need are the mouthpiece adapter, some pvc fittings, an air
hose from your scuba tank to the regulator, an air hose going from the regulator
mouthpiece to the thru the hull air fitting the hose attaches to going into your
pod, and that's the system.
Now you can also install leak sensors if you wish, as well as make
your pod automatically vent air into the pod if water leaks in to force the
water back out. In the event this occured you would hopefully
notice the gauge on your air tank was going
down rapidly or even hear the hiss of the air going into the pod and
forcing the water out. It would do this til your tank was empty so if this ever
happened you have but a short time to surface and hopefully before your air
is gone from trying to purge the
water from your battery pod. Of course you don't have to install leak
sensors and hook it up to where the air will purge any water, you could just use
the system I explained above and not use sensors or purging at all. But you
had better be very sure of
your O ring seals and any thru the pod fittings being watertight,
because if they are not, if you have a leak the water will simply fill the
battery pod and your scuba regulator pressure equalization system would not
automatically purge it because it only would
vent air into the pod to equalize pressure from where the water was trying
to vill an air void, and since that void no longer exists and your pod is full
of water now, the regulator would not vent air into it automatically. You could
of course do it manually by
pressing on the purge valve button of the regulator, but you wouldn't know
how much was needed, but you could just hold the button down if you knew your
pod was flooded and let the air constantly flow into the pod to purge the
water out and thru your
scuba regulator's exhaust ports, and while you were doing this you had
better surface as soon as possible. So although you don't absolutely have to
have a leak sensor water purge system, it is nice to have and I would reccommend
it. I have been reading on
this subject and am going to install leak sensors on my pod so that not
only will my pressure equalization system work automatically, but I will also
have an automatic purge system if my leak sensors detect a leak. Still have to
get to the surface though. The thing the leak sensors do is they detect a leak
you wouldn't otherwise know about til it was too late and they give you time and
hopefully you can surface before the pod floods and your leak sensors will have
kept air going into the pod while this was happening and hopefully your
batteries will not be damaged not to mention create chlorine gas.
I hope I have written this so that you understand what I mean. I am by no
means an expert, and I am building this myself and learning as I go along. But I
am sure the above system is correct and will work.
Kindest Regards,
Bill Akins.
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