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RE: [PSUBS-MAILIST] Regulators
Yes. I used to have a SCUBA regulator permanently piped into the main
SCUBA tanks, but now have switched to carrying two "Spare Air" units.
-----Original Message-----
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of
MerlinSub@t-online.de
Sent: Friday, December 31, 2010 5:44 AM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Regulators
Alec do you have emergency suba breathing device on board for each
person - in case of a small fire?
vbr Carsten
"Smyth, Alec" <Alec.Smyth@compuware.com> schrieb:
> Hi Hugh,
>
> In his book, Kittredge describes how for many years he used the "SAR"
method. It's a laugh because it sounds very high tech but means nothing
more than "Surface And Replenish". This was the method he knew from Navy
submarines in WWII. It is quite adequate for a K boat if you're making
short dives. Typically we set the dive timer at 20 minutes, and the air
doesn't feel stale for an hour and a half hours. I have to admit,
although I've got an O2 meter on board I can't recall the reading after
20 minutes because it's an absolute non-issue.
>
> Snoopy also has a scrubber, an O2 regulator, and a barometer. No
automation to the O2 injection, you would just adjust the flow rate
every so often based on the evolution of cabin pressure. What I've done
thus far is dive with a full tank of O2, the tank valve open, but the
hull stop closed. The Sofnolyme is in a sealed plastic container, not
loaded into the scrubber. If I did get caught up on something and
couldn't surface, I'd have plenty of time to load the scrubber and turn
on the O2, but I've never needed to. I do anticipate changing this SOP
to using life support on two person dives. Not so much because I would
need life support for a 20 minute dive, as much as because the boat is
so cramped with two people that it would be much more of a hassle
filling the scrubber!
>
> The medical regulator I've got is like eBay item 150464127173. Cheap
little things. They come in a variety of flow rates, but the lower ones
like 0-4 lpm would give you the best fine tuning. Search on "pediatric
medical regulator", as "pediatric" will zero in on the ones with low
flow rates. A person consumes roughly 1 lpm at rest, so there's no point
in using a regulator that delivers 15 lpm, as you would lose out on
adjustability.
>
> Snoopy's life support is decidedly elementary, but one nice innovation
I'm working on now is an almost-off-the-shelf scrubber. More on that in
a couple of weeks!
>
> Thanks,
>
> Alec
>
>
>
>
> ________________________________
>
> From: owner-personal_submersibles@psubs.org on behalf of Hugh Fulton
> Sent: Thu 12/30/2010 5:53 PM
> To: personal_submersibles@psubs.org
> Subject: RE: [PSUBS-MAILIST] Regulators
>
>
>
> Hi Alec,
>
> That is interesting that you don't use O2 for short dives. What O2
percentage level do you consider it is OK down to?
>
>
>
> I guess that if you have 1 cubic meter of free air space it would take
1.8 hours at ABS .47 litres / minute to reduce to 15% and that would be
850 mbars then you could add a bit of air which would then bring it up
to about 17% providing of course that you are scrubbing.
>
>
>
> Saves on costs. What are the negatives if you are only doing 1-1.5
hours at a time.
>
> Does anyone else do this?
>
>
>
> What is the medical O2 regulator brand you are using?
>
>
>
> Regards,
>
> Hugh
>
>
>
>
>
>
>
> From: owner-personal_submersibles@psubs.org
> [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Smyth,
> Alec
> Sent: Friday, 31 December 2010 9:16 a.m.
> To: personal_submersibles@psubs.org
> Subject: RE: [PSUBS-MAILIST] Regulators
>
>
>
> Hi Hugh,
>
>
>
> It's a little of a tangent, but I've just got rid of the air
regulators altogether. I stole the idea from Greg Cottrell, on the basis
that the fewer moving parts is best. I simply pipe in HP air with
Swagelok tubing and regulate the MBT blows with needle valves. Of course
there's still hull stops, and a cross-over valve allowing you to supply
the blow line for both tanks from either bottle, but it is certainly a
simpler setup.
>
>
>
> For O2, the regulator should ideally go outside as low pressure O2 is
far less likely to ignite than HP, and if an O2 fire is to occur, it
would be rather nicer to leave it on the outside. I can't recall what
brand my O2 regulator is, it's just a SCUBA 1st stage cleaned for use
with 100% O2. The 1st stage feeds a little medical O2 metered regulator
that's inside. I'm sure there are much more sophisticated solutions, and
must admit I've never even turned on my O2 system because my dives are
too short to need it, but I expect that to change next time out since
Snoopy is now a 2 person boat.
>
>
>
>
>
> Thanks,
>
>
> Alec
>
>
>
>
>
>
>
>
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> From: owner-personal_submersibles@psubs.org
> [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Hugh
> Fulton
> Sent: Thursday, December 30, 2010 2:53 PM
> To: personal_submersibles@psubs.org
> Subject: [PSUBS-MAILIST] Regulators
>
> Placement of regulators and choice of them.
>
> For Air and oxygen. Is it best to have the regulators inside or
outside the pressure hull? I noticed that some have the regs outside
and others inside.
>
> What brand/models have people found the best? Hugh
>
>
>
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