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<DIV><FONT size=3>Keith,</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=3>At 33 feet you would have to have double the atmospheric
pressure inside the sub to have an over pressure situation (actually it would be
equal at that point). Hopefully you would already be headed to the
surface, and your OP valve would begin venting as you ascended and the water
pressure decreased.</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=3>To have an OP situation at that depth you would have to have a
leak from your ballast air system or your oxygen system. If the exterior
exit of the OP valve has a U bend to point downward, you should still have
little if any water intrusion.</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=3>Jim</FONT></DIV>
<DIV> </DIV>
<DIV>
<DIV>In a message dated 6/19/2015 2:08:04 A.M. Central Daylight Time,
personal_submersibles@psubs.org writes:</DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2
face=Arial>Jim,<BR><BR>Thanks for the mental diagram, that helps imensely.
Does any one know how the big boys, navy subs, deal with over pressure? Has
any one had their OP valve open at depth and if so how much water came
in?<BR><BR>Keith T<BR><BR>via Personal_Submersibles
<personal_submersibles@psubs.org> wrote:<BR><BR>>Keith,<BR>>
<BR>>Sorry, I just got home. I was hoping Alec and some others
with more <BR>>experience than I have would chime in as I see has now
happened. There have <BR>>been some good discussions on OP valves in
the past. I think some have <BR>>installed a T (on its side)
inside the sub so the air enters the horizontal <BR>>portion, and any
water that comes in goes down to a small trap or into a tube
<BR>>that leads to a reservoir. Others just use a rag to catch
the small amount <BR>>of water.<BR>> <BR>>Alec, does the OP on the
exterior of Snoopy point downward after it exits <BR>>at the
top?<BR>> <BR>>We've also discussed having an air pressure gauge or
altimeter set to zero <BR>>(1 atm) before diving. If it
indicates any pressure above that level at <BR>>anytime during your
dive, you'll know you'll have an over pressure situation <BR>>to deal
with as you surface and you'll have an indication of how severe
<BR>>that will be. We've also discussed various things that could
cause an over <BR>>pressure condition.<BR>> <BR>>Best
regards,<BR>>Jim<BR>> <BR>> <BR>>In a message dated 6/18/2015
7:09:19 P.M. Central Daylight Time,
<BR>>personal_submersibles@psubs.org writes:<BR>><BR>>If it opens
when submerged, it is because air is on the way out, and that
<BR>>prevents water from coming in. Its like blowing through your
nose <BR>>underwater, your nose is open but if you're blowing, you
don't get water in your <BR>>lungs.
<BR>><BR>><BR>>Certainly you do get a little water in if you push the
valve open manually <BR>>while submerged, as a test. Or a few drops
if you do so when surfaced to <BR>>equalize, as the valve is all wet.
But its nothing
much.<BR>><BR>><BR>><BR>>Best,<BR>><BR>>Alec<BR>><BR>><BR>><BR>>On
Thu, Jun 18, 2015 at 7:19 PM, Ken Martindale via Personal_Submersibles
<BR>><_personal_submersibles@psubs.org_
(mailto:personal_submersibles@psubs.org) <BR>>>
wrote:<BR>><BR>>TEST!!!<BR>><BR>>-----Original
Message-----<BR>>From: Personal_Submersibles
<BR>>[mailto:_personal_submersibles-bounces@psubs.org_
(mailto:personal_submersibles-bounces@psubs.org) ] On Behalf Of via
<BR>>Personal_Submersibles<BR>>Sent: Thursday, June 18, 2015 4:28
PM<BR>>To: Personal Submersibles General Discussion<BR>>Subject:
Re: [PSUBS-MAILIST] Over Pressure Valve<BR>><BR>>How do you keep
water from going back down the valve, and into the sub, if <BR>>it
opens when submerged?<BR>><BR>>Keith T<BR>><BR>>via
Personal_Submersibles <_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) >
wrote:<BR>><BR>>>If the pressure differential exceeds the
preset cracking pressure, the<BR>>>valve will open on its
own to relieve the excess pressure. If the
<BR>>pressure<BR>>>differential is less than the cracking
pressure, it would have to be<BR>>>opened manually. If
the differential were only slightly greater than<BR>>>the preset
cracking pressure, I suppose opening it manually would
open<BR>>>it wider for more rapid equalization on many types of
valves.<BR>>>Jim<BR>>><BR>>><BR>>>In a message dated
6/18/2015 2:40:58 P.M. Central Daylight
Time,<BR>>>_personal_submersibles@psubs.org_
(mailto:personal_submersibles@psubs.org) <BR>>
writes:<BR>>><BR>>><BR>>>Jim,<BR>>>
In that case is it necessary to bump the sealed
check valve<BR>>>to make it
open?<BR>>><BR>>><BR>>>Alec, I guess what I
meant to say was if the check valve is left in<BR>>>an open line
to the outside all the time, rather than being isolated
by<BR>>>another
valve.<BR>>><BR>>>Brian<BR>>><BR>>>---
_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org)
wrote:<BR>>><BR>>>From: via Personal_Submersibles
<_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org)
><BR>>>To: _personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) <BR>>>Subject:
Re: [PSUBS-MAILIST] Idea..?<BR>>>Date: Thu, 18 Jun 2015
14:53:15 -0400<BR>>><BR>>><BR>>><BR>>>Brian, it
also has to do with cracking pressure. When you surface
the<BR>>>sub might be slightly over pressure but not with
enough differential<BR>>>to open the valve
automatically. That's when you open it
manually.<BR>>>That would also equalize pressure if you have
negative pressure in the<BR>>>sub to make it a whole lot
easier to open the
hatch.<BR>>>Jim<BR>>><BR>>><BR>>>In a message dated
6/18/2015 1:40:32 P.M. Central Daylight
Time,<BR>>>_personal_submersibles@psubs.org_
(mailto:personal_submersibles@psubs.org) <BR>>
writes:<BR>>><BR>>>It is nothing but a T shape sealed by a spring.
If internal pressure<BR>>>builds up, it pushes the spring
and the valve opens. So it is a<BR>>>normally closed valve... but
I suppose you could say its "open all the<BR>>>time" in the
sense that anytime pressure builds up, it will
open.<BR>>><BR>>>On Thu, Jun 18, 2015 at 2:35 PM, Brian Cox
via
Personal_Submersibles<BR>>><_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) )
><BR>>>wrote:<BR>>><BR>>><BR>>>Couldn't you,
theoretically, have that valve open to the outside all
<BR>>the<BR>>>time?<BR>>><BR>>>Brian<BR>>><BR>>>---
_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) )
wrote:<BR>>><BR>>>From: Alec Smyth via
Personal_Submersibles<BR>>><_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) )
><BR>>>To: Personal Submersibles General
Discussion<BR>>><_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) )
><BR>>>Subject: Re: [PSUBS-MAILIST] Idea..?<BR>>>Date:
Thu, 18 Jun 2015 12:15:57
-0400<BR>>><BR>>><BR>>><BR>>><BR>>>I think
most have an OP valve, and I'd strongly encourage any
who<BR>>>don't to put one in. If you read Kittredge's book, the
lack of an OP<BR>>>valve was the cause of the only K-boat accident
so far. Fortunately<BR>>>nothing happened to him, but Kittredge
had a slow cabin air leak during<BR>>>his dive and upon surfacing
blew out the dome when just below the<BR>>>surface. He was
blown out himself with it. The sub sank, and he<BR>>>proceeded
to re-float it without losing beat. I use the OP
valve<BR>>>routinely to equalize pressure so I can open the
hatch easily. Just a<BR>>>little push on the stem does it.
One thing about OP valves, they have<BR>>>to be capable of
handling large flow rates. Don't use a little Swagelok <BR>>check
valve or such small
thing.<BR>>><BR>>><BR>>>Best,<BR>>><BR>>>Alec<BR>>><BR>>><BR>>><BR>>><BR>>><BR>>><BR>>><BR>>>On
Thu, Jun 18, 2015 at 10:55 AM, Brian Cox via
Personal_Submersibles<BR>>><_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) )
><BR>>>wrote:<BR>>><BR>>>Also Alec, I
noticed your check valve overpressure valve in the
photo<BR>>>section. That seems like a great solution to
the problem! I guess I <BR>>was<BR>>>not
aware of that, does everybody have one of
those?<BR>>><BR>>><BR>>>Brian<BR>>><BR>>>---
_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) )
wrote:<BR>>><BR>>>From: hank pronk via
Personal_Submersibles<BR>>><_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) )
><BR>>>To: Personal Submersibles General
Discussion<BR>>><_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) )
><BR>>>Subject: Re: [PSUBS-MAILIST] Idea..?<BR>>>Date:
Thu, 18 Jun 2015 05:25:30
-0700<BR>>><BR>>><BR>>><BR>>>personally, I
always avoid welding a machined part to the hull.
I<BR>>>weld a flange or nipple to the hull then bolt or
thread the machined <BR>>part to that.<BR>>> This is my
solution to a lack of tooling and
expertise.<BR>>>Hank
--------------------------------------------<BR>>>On Thu, 6/18/15,
James Frankland via
Personal_Submersibles<BR>>><_personal_submersibles@psubs.org_
<BR>>(mailto:_personal_submersibles@psubs.org_
(mailto:personal_submersibles@psubs.org) ) >
wrote:<BR>>><BR>>>Subject: Re: [PSUBS-MAILIST]
Idea..?<BR>>>To: "Personal Submersibles General
Discussion"<BR>>><_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) )
><BR>>>Received: Thursday, June 18, 2015, 4:58
AM<BR>>><BR>>>Hi<BR>>>Alec\Brian, Yes, maybe it
would<BR>>>push in. A flat step would probably be better
like you<BR>>>say. But maybe im over thinking it as
usual. Probably<BR>>>not required. Brian, I used
the<BR>>>5\8ths bar because that's what was specified on
the<BR>>>plans. However, its also convenient for using a
16mm<BR>>>reamer for the
bore.<BR>>>regardsJames<BR>>>On 18 June 2015 at
03:04,<BR>>>Brian Cox via Personal_Submersibles
<_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) )
><BR>>>wrote:<BR>>>Oh cool ! Thanks
Alec<BR>>>! I owe you much over the
years<BR>>>! Brian<BR>>>---
_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org)
)<BR>>>wrote:<BR>>><BR>>>From: Alec Smyth
via<BR>>>Personal_Submersibles
<_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) )
><BR>>>To: Personal Submersibles General
Discussion<BR>>><_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org)
)<BR>>>><BR>>>Subject: Re: [PSUBS-MAILIST]
Idea..?<BR>>>Date: Wed, 17 Jun 2015 16:40:56
-0400<BR>>><BR>>>Hi Brian,<BR>>>I tend to use
quite thick<BR>>>through-hulls because its easier for me to
machine the O-ring grooves<BR>>>into the shaft than into the
insert. In my case its just a matter of<BR>>>the tooling I
have on hand. If you have the tooling to put the
grooves<BR>>>in the insert, half an inch is fine for
many
applications.<BR>>>Best,<BR>>><BR>>>Alec<BR>>>On<BR>>>Wed,
Jun 17, 2015 at 3:22 PM, Brian Cox via
Personal_Submersibles<BR>>><_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) )
><BR>>>wrote:<BR>>>Alec, James,
I'm<BR>>>using mostly 1/2" stainless rod through-out for
most all of my hull<BR>>>penetrations ( for valves and
flaps) , I noticed in the example it<BR>>>was a 5/8"
rod, Why such a heavy duty thickness? Was that for
a<BR>>>particular function? Brian<BR>>><BR>>>---
_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org)
)<BR>>>wrote:<BR>>><BR>>>From: Alec Smyth
via<BR>>>Personal_Submersibles
<_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) )
><BR>>>To: Personal Submersibles General
Discussion<BR>>><_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org)
)<BR>>>><BR>>>Subject: Re: [PSUBS-MAILIST]
Idea..?<BR>>>Date: Wed, 17 Jun 2015 14:03:17
-0400<BR>>><BR>>>Hi James,<BR>>>I think<BR>>>with the
taper, this would tend to push in and jam. The idea is
neat,<BR>>>however, and would probably work fine with a step
instead of a taper.<BR>>>On the other hand, does an O ring
sealed through-hull ever fail<BR>>>catastrophically? I've had the
odd drip, but that's all I've bad as<BR>>>I've
seen.<BR>>>Best,<BR>>>Alec<BR>>>On<BR>>>Wed, Jun
17, 2015 at 12:26 PM, James Frankland
via<BR>>>Personal_Submersibles
<_personal_submersibles@psubs.org_<BR>>>(mailto:_personal_submersibles@psubs.org_
<BR>>(mailto:personal_submersibles@psubs.org) )
><BR>>>wrote:<BR>>>Hi All Seeing as its a<BR>>>bit
quite I thought I would show this idea. Its super
simple.... I<BR>>>have been thinking how you could stop a
leaking through hull.<BR>>>Thinking of K boat type 5\8th
through hulls as in the plans. I<BR>>>believe Scott had a leak
when he did his deep test due to a faulty
O<BR>>>ring?<BR>>><BR>>>Anyway, here is my idea.
It<BR>>>would take a little bit more machining, but not
much.<BR>>>Machine the 5\8ths bar with a taper on the
protruding part and a taper<BR>>>on the top to help push the
bar through.<BR>>>(I did that on mine anyway). The
handle is made with a cam type end.<BR>>><BR>>>If you
get a<BR>>>leak, you can pull the handle up. The bar
would be pulled up, forcing<BR>>>the taper to jam into the
penetrator, hopefully stopping most of the<BR>>>leak.
I suppose you could even machine a matching taper into
the<BR>>>start of the through hull to match? I suppose the
bar could get pushed<BR>>>through and jam on its own.
That's a possibility. Pic attached.
Kind<BR>>>RegardsJames
<BR>>><BR>>>_______________________________________________<BR>>><BR>>>Personal_Submersibles
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