Dan,
You are correct in your thought process concerning the
use of a Schraeder (tire) valve for the possible injection of air into the
submersible and the subsequent rise in internal pressure.
The dive industry has moved away from Schrader valves
for those life support applications that involve breathing as it is limited in
the volume rate that it can pass. Additionally, the rescuers will
probably find it inconvenient if not impossible to maintain a connection with
the Schraeder valve for any length of time (plus they are very susceptible to
fouling, corrosion, and bending the internal stem pin). Cold water makes
working with Schraeder fittings even more difficult due to bulky
gloves.
Depending on the emergency situation, your bottom time
might be very lengthy before the rescue can be affected. Case in point
was the Russian research sub that was stranded off of the west coast of Russia
a few years ago and the Johnson Sea Link quite awhile ago. The sub's
locations were known but it took awhile to get them back to the surface.
Increasing the submarine's internal pressure to even minor over pressures will
lead to the incursion of a significant decompression obligation. Without
the means to control the internal pressure while rescuers bring the sub to the
surface will lead to explosive decompression sickness and/or arterial gas
embolism (AGE). The sub is designed to keep the pressure out, not keep
it in and you may find that it will be difficult to gradually decrease the
sub's internal pressure when surfacing. Unfortunately most of our PSUBs
are too small to have a mating ring attached to dock with a surface
decompression chamber to allow transfer of the sub’s occupants into a surface
chamber.
All scientific, military, and tourists submersibles are
fitted with external emergency air fittings these days. It took some
nasty incidents in the 20's and 30's for this design change to occur. In
the US, the US Coast Guard should be notified immediately for a SUBMISS or
SUBSUNK incident. They will contact the US Navy who will take over and
coordinate rescue efforts. One of the first questions the Navy will ask
is what emergency air fittings are installed. This will be similar in
most other countries who will most likely contact the International Submarine
Escape and Rescue Liaison Office (ISMERLO) and the US Navy may still be the
response organization.
Based upon the presentation that I made at the last PSUB
Conference, extensive discussions outside of the meeting room, and initial
contact made with the US Coast Guard in Rockland, ME (local jurisdiction for
the upcoming conference), I propose that we have a 2-part rescue workshop
including in the upcoming conference. The workshop would have a
discussion session where ideas are tossed around (this can start earlier over
the web) that leads to some consensus as to the steps to be taken to affect
getting a stranded PSUB back to the surface. The discussion session
would be followed by a practical session at the waterfront where we would
actually work at bringing a hull to the surface. I would invite the USCG
to participate in both of these sessions. These sessions would be
followed with my traditional dispensing of rum rations of course to ward off
the cold of the Maine waters! J
R/Jay
Respectfully,
Jay K. Jeffries
Andros Is., Bahamas
A skimmer afloat is but a submarine, so poorly built it
will not plunge.
-----Original Message-----
From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Dan. H.
Sent:
Sunday, January 06, 2008 1:22 PM
To:
personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Viewport
Question.
Jay,
The rescuers suggestion of an air inlet was more to
offer some additional
time to be submerged, in case of entanglement or what
ever. The team
already has a setup to inject air in a tire valve type
fitting. I may be
wrong in my thinking ,but wouldn't newly injected air
dilute the stale air
in a stranded sub? Even better, if the person in
the sub was conscious,
they could breath directly from the inlet and exhale in
the sub.
I know it would increase the internal pressure unless
the stale air was
pumped out, but increasing the internal pressure may be
the least of your
worries if your trapped inside for a
while.
The way my sub is set up now, I could receive air
through my snorkel inlet,
but I would have to be conscious to open the valve
inside the sub. The
rescuers could unscrew the external float valve and
screw on an adaptor with
a tire valve in it. Then once I open the internal
snorkel valve, the air
would come through.
Am I correct?
Dan H.
----- Original Message -----
From: "Jay K. Jeffries"
<bottomgun@mindspring.com>
To:
<personal_submersibles@psubs.org>
Sent: Sunday, January 06, 2008 12:05 PM
Subject: RE: [PSUBS-MAILIST] Viewport
Question.
> Dan,
> Remember that you will need to fittings...an inlet
and an outlet if you
> are
> to maintain atmospheric pressure inside the
stranded submersible. Plus
> you
> will need a rescue force familiar with your setup
and the necessary
> equipment to affect rescue support.
> R/Jay
>
>
> Respectfully,
> Jay K. Jeffries
> Andros Is., Bahamas
>
> A skimmer afloat is but a submarine, so poorly
built it will not plunge.
>
> -----Original Message-----
> From:
owner-personal_submersibles@psubs.org
> [mailto:owner-personal_submersibles@psubs.org] On
Behalf Of Dan. H.
> Sent: Sunday, January 06, 2008 11:36
AM
> To: personal_submersibles@psubs.org
> Subject: Re: [PSUBS-MAILIST] Viewport
Question.
>
> Some members of our local dive rescue team looked
over my sub after it was
> completed. One recommendation they had was to
add a fitting and valve on
> the outside of the hull to allow them to inject air
into the hull if I was
> inside and unconscious. I never added it
because I didn't like the idea
> of
> an open line into the hull without being in some
closed system or with a
> closed valve on it. It may be a nice
addition. At least, someone could
> dilute a contaminated atmosphere in the sub or
increase the hull pressure
> if
>
> needed.
>
> Just a thought,
> Dan H.
>
>
>
>
>
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