<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content="text/html; charset=US-ASCII" http-equiv=Content-Type>
<META name=GENERATOR content="MSHTML 11.00.9600.17842"></HEAD>
<BODY id=role_body style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; COLOR: #000000"
bottomMargin=7 leftMargin=7 rightMargin=7 topMargin=7><FONT id=role_document
color=#000000 size=2 face=Arial>
<DIV><FONT size=3>Alan,</FONT></DIV>
<DIV><FONT size=3>I'll bring it up at the convention next week during the open
forum and see what everyone thinks. I've always used absolute in this
context because I'm referring to a 1ATM sub and by inference consider the
pressure in the sub to be 1ATM. However I might be out of step with the
way others reference it. I can understand referring to the pressure
differential at 33' as 1ATM; I'm just accustomed to referring to the absolute
pressure.</FONT></DIV>
<DIV><FONT size=3>Jim</FONT></DIV>
<DIV> </DIV>
<DIV>
<DIV>In a message dated 6/19/2015 11:00:57 P.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>
<DIV
style="FONT-SIZE: 16px; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; COLOR: #000; BACKGROUND-COLOR: #fff">
<DIV id=yui_3_16_0_1_1434772006747_2820><SPAN
id=yui_3_16_0_1_1434772006747_2821>OK,</SPAN></DIV>
<DIV id=yui_3_16_0_1_1434772006747_2820><SPAN> as a group, do we have to
designate psig or psia to be on the same page.</SPAN></DIV>
<DIV id=yui_3_16_0_1_1434772006747_2820><SPAN
id=yui_3_16_0_1_1434772006747_2920>In some industries if there is no
designation it is assumed to be psig, (gauge) whereas</SPAN></DIV>
<DIV id=yui_3_16_0_1_1434772006747_2820 dir=ltr><SPAN
id=yui_3_16_0_1_1434772006747_2924>in other industries it is assumed to be
psia (absolute). & we are using guages (psig)</SPAN></DIV>
<DIV id=yui_3_16_0_1_1434772006747_2820 dir=ltr><SPAN
id=yui_3_16_0_1_1434772006747_3021>& barometers (that show a negative
pressure relative to our 1 atm).</SPAN></DIV>
<DIV id=yui_3_16_0_1_1434772006747_2820 dir=ltr><SPAN
id=yui_3_16_0_1_1434772006747_3129>Is their a nautical or submarine standard?
Does anyone else have an opinion on this?</SPAN></DIV>
<DIV id=yui_3_16_0_1_1434772006747_2820 dir=ltr><SPAN>Alan</SPAN></DIV>
<DIV id=yui_3_16_0_1_1434772006747_2820 dir=ltr><SPAN><BR></SPAN></DIV>
<DIV id=yui_3_16_0_1_1434772006747_2820 dir=ltr><SPAN><BR></SPAN></DIV><BR>
<DIV id=yui_3_16_0_1_1434772006747_2724
style="FONT-SIZE: 16px; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif">
<DIV id=yui_3_16_0_1_1434772006747_2723
style="FONT-SIZE: 16px; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif">
<DIV id=yui_3_16_0_1_1434772006747_2741 dir=ltr>
<HR id=yui_3_16_0_1_1434772006747_2850 SIZE=1>
<FONT id=yui_3_16_0_1_1434772006747_2819 size=2 face=Arial><B
id=yui_3_16_0_1_1434772006747_2818><SPAN id=yui_3_16_0_1_1434772006747_2817
style="FONT-WEIGHT: bold">From:</SPAN></B> via Personal_Submersibles
<personal_submersibles@psubs.org><BR><B
id=yui_3_16_0_1_1434772006747_3207><SPAN id=yui_3_16_0_1_1434772006747_3206
style="FONT-WEIGHT: bold">To:</SPAN></B> personal_submersibles@psubs.org
<BR><B id=yui_3_16_0_1_1434772006747_3209><SPAN
id=yui_3_16_0_1_1434772006747_3208 style="FONT-WEIGHT: bold">Sent:</SPAN></B>
Saturday, June 20, 2015 3:21 PM<BR><B><SPAN
style="FONT-WEIGHT: bold">Subject:</SPAN></B> Re: [PSUBS-MAILIST] Over
Pressure Valve<BR></FONT></DIV>
<DIV id=yui_3_16_0_1_1434772006747_2722 class=y_msg_container><BR>
<DIV id=yiv3895412105>
<DIV id=yui_3_16_0_1_1434772006747_2740><FONT id=yiv3895412105role_document
color=#000000 size=2 face=Arial></FONT>
<DIV id=yui_3_16_0_1_1434772006747_2739><FONT size=3>Hi Alan,</FONT></DIV>
<DIV id=yui_3_16_0_1_1434772006747_2849><FONT
id=yui_3_16_0_1_1434772006747_2848 size=3>Cracking pressure only relates to
the pressure differential from one side of the valve to the other.
There's no relevance to absolute pressure.</FONT></DIV>
<DIV id=yui_3_16_0_1_1434772006747_2852><FONT size=3>Jim</FONT></DIV>
<DIV id=yui_3_16_0_1_1434772006747_2853> </DIV>
<DIV id=yui_3_16_0_1_1434772006747_2747>
<DIV id=yui_3_16_0_1_1434772006747_2854>In a message dated 6/19/2015 9:45:45
P.M. Central Daylight Time, personal_submersibles@psubs.org writes:</DIV>
<BLOCKQUOTE id=yui_3_16_0_1_1434772006747_2746
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2
face=Arial></FONT>
<DIV class=qtdSeparateBR><BR><BR></DIV>
<DIV id=yiv3895412105yqt61405 class=yiv3895412105yqt7069744715>
<DIV id=yui_3_16_0_1_1434772006747_2745
style="FONT-SIZE: 16px; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; COLOR: #000; BACKGROUND-COLOR: #fff">
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23128><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_23481>Hi Jim,</SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23128 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_23161>it's a confusing way of
looking at it.</SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23128 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_23159>If I say that my
overpressure valve has a 1psi cracking pressure, everyone knows</SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23128 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_23415>what I am talking about. If
I say it has a 15.7psi cracking pressure (1 atm + 1psi)</SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23128 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_23416>everybody is going to think
I am going to blow my dome off before I relieve pressure.</SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23128 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_23417>You are Americanizing this
too much & need to get back to basic Queens English.</SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23128 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_23418>I'll have my pressure gauge
set at 0 not 14.7 as it will confuse things.</SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23128 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_23419>It's pretty wet here over
the Winter. The last 2 years I've escaped to Thailand for</SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23128 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_23607>Dental work & lots of
snorkeling. There are some mind blowing snorkeling / diving spots
there.</SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23128 dir=ltr>p.s. Are your
tyres feeling flat? :)<BR clear=none></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23128
dir=ltr><SPAN>Alan</SPAN></DIV><BR clear=none>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23131
style="FONT-SIZE: 16px; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif">
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23130
style="FONT-SIZE: 16px; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif">
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23129 dir=ltr>
<HR id=yiv3895412105yui_3_16_0_1_1434762674281_23132 SIZE=1>
<FONT id=yiv3895412105yui_3_16_0_1_1434762674281_23162 size=2
face=Arial><B><SPAN style="FONT-WEIGHT: bold">From:</SPAN></B> via
Personal_Submersibles <personal_submersibles@psubs.org><BR
clear=none><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B>
personal_submersibles@psubs.org <BR clear=none><B><SPAN
style="FONT-WEIGHT: bold">Sent:</SPAN></B> Saturday, June 20, 2015 1:58
PM<BR clear=none><B id=yiv3895412105yui_3_16_0_1_1434762674281_23660><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_23659
style="FONT-WEIGHT: bold">Subject:</SPAN></B> Re: [PSUBS-MAILIST] Over
Pressure Valve<BR clear=none></FONT></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23163
class=yiv3895412105y_msg_container><BR clear=none>
<DIV id=yiv3895412105>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23166><FONT
id=yiv3895412105role_document color=#000000 size=2 face=Arial></FONT>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23165><FONT
id=yiv3895412105yui_3_16_0_1_1434762674281_23164 size=3>Yup, Alan, that's
me. I'm using Psubs vernacular as in a 1ATM sub having an internal
pressure equal to sea level pressure or 1ATM or 14.7 psi (absolute
pressure). You're using the vernacular I use when I'm airing up
the tires on my trailer and say I have 32 psi in the tire (tyre to
you). In that conversation we're referring to differential or gauge
pressure. Since your vessel is an ambient, I can where the confusion
would come in.</FONT></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23661><FONT
size=3></FONT> </DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23663><FONT
id=yiv3895412105yui_3_16_0_1_1434762674281_23662 size=3>Now about you guys
in NZ having winter in the middle of summer...</FONT></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23670><FONT
size=3></FONT> </DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23664><FONT
size=3>JT</FONT></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23750> </DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23666>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23665>In a message dated
6/19/2015 8:42:43 P.M. Central Daylight Time,
personal_submersibles@psubs.org writes:</DIV>
<BLOCKQUOTE id=yiv3895412105yui_3_16_0_1_1434762674281_23668
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2
face=Arial></FONT>
<DIV id=yui_3_16_0_1_1434772006747_2744
class=yiv3895412105qtdSeparateBR><BR clear=none><BR clear=none></DIV>
<DIV id=yiv3895412105yqt98482 class=yiv3895412105yqt2788981910>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_23667
style="FONT-SIZE: 16px; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; COLOR: #000; BACKGROUND-COLOR: #fff">
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5684><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_5683>Hi Jim,</SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5684 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_8887>as you were talking of
pressures in a range outside of</SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5684 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_8886>that of a normal
barometer, it was assumed that you were talking </SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5684 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_8847>about a normal pressure
gauge reading & using standard vernacular.</SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5684 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_23669>That's Jim Todd isn't it.
I don't want to get too cheeky with the wrong person:)</SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5684 dir=ltr><SPAN>Cheers
Alan</SPAN></DIV><BR clear=none>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5689
style="FONT-SIZE: 16px; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif">
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5688
style="FONT-SIZE: 16px; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif">
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5687 dir=ltr>
<HR id=yiv3895412105yui_3_16_0_1_1434762674281_8676 SIZE=1>
<FONT id=yiv3895412105yui_3_16_0_1_1434762674281_5690 size=2
face=Arial><B><SPAN style="FONT-WEIGHT: bold">From:</SPAN></B> via
Personal_Submersibles <personal_submersibles@psubs.org><BR
clear=none><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B>
personal_submersibles@psubs.org <BR clear=none><B><SPAN
style="FONT-WEIGHT: bold">Sent:</SPAN></B> Saturday, June 20, 2015 12:52
PM<BR clear=none><B><SPAN style="FONT-WEIGHT: bold">Subject:</SPAN></B>
Re: [PSUBS-MAILIST] Over Pressure Valve<BR clear=none></FONT></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5691
class=yiv3895412105y_msg_container><BR clear=none>
<DIV id=yiv3895412105>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5719><FONT
id=yiv3895412105role_document color=#000000 size=2 face=Arial></FONT>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5773><FONT
id=yiv3895412105yui_3_16_0_1_1434762674281_23751 size=3>Hi
Alan,</FONT></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5771><FONT
id=yiv3895412105yui_3_16_0_1_1434762674281_5772 size=3>I'm speaking in
terms of absolute pressure. That is, pressure at the surface being
14.7 psi or 1 atm and water pressure at 33 feet deep being 2
atm. I think you're speaking comparatively as though air
pressure at the surface were 0.0 psi. Right?</FONT></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5770><FONT
size=3>Jim</FONT> </DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5769> </DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5718>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5717>In a message dated
6/19/2015 4:46:04 P.M. Central Daylight Time,
personal_submersibles@psubs.org writes:</DIV>
<BLOCKQUOTE id=yiv3895412105yui_3_16_0_1_1434762674281_5721
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2
face=Arial></FONT>
<DIV id=yui_3_16_0_1_1434772006747_2748
class=yiv3895412105qtdSeparateBR><BR clear=none><BR clear=none></DIV>
<DIV id=yiv3895412105yqt07474 class=yiv3895412105yqt4288363635>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5720
style="FONT-SIZE: 16px; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; COLOR: #000; BACKGROUND-COLOR: #fff">
<DIV id=yiv3895412105yui_3_16_0_1_1434749417686_22281 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434749417686_22291>Jim,</SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434749417686_22281 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434749417686_22327>>>></SPAN><SPAN
id=yiv3895412105yui_3_16_0_1_1434749417686_22328
style="FONT-SIZE: medium; FONT-FAMILY: 'Helvetica Neue', 'Segoe UI', Helvetica, Arial, 'Lucida Grande', sans-serif"> </SPAN><SPAN
id=yiv3895412105yui_3_16_0_1_1434749417686_22290
style="FONT-SIZE: medium; FONT-FAMILY: 'Helvetica Neue', 'Segoe UI', Helvetica, Arial, 'Lucida Grande', sans-serif">If
the air pressure inside your sub rose to 20 psi or about 1.33
atm, you would reach equal pressure when you got within 11 feet of the
surface. </SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434749417686_22281 dir=ltr><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_11822
style="FONT-SIZE: medium; FONT-FAMILY: 'Helvetica Neue', 'Segoe UI', Helvetica, Arial, 'Lucida Grande', sans-serif">
No 40ft. </SPAN></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434749417686_22281 dir=ltr><SPAN
style="FONT-SIZE: medium; FONT-FAMILY: 'Helvetica Neue', 'Segoe UI', Helvetica, Arial, 'Lucida Grande', sans-serif">Alan</SPAN></DIV><BR
clear=none>
<DIV id=yiv3895412105yui_3_16_0_1_1434749417686_22265
style="FONT-SIZE: 16px; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif">
<DIV id=yiv3895412105yui_3_16_0_1_1434749417686_22264
style="FONT-SIZE: 16px; FONT-FAMILY: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif">
<DIV id=yiv3895412105yui_3_16_0_1_1434749417686_22263 dir=ltr>
<HR id=yiv3895412105yui_3_16_0_1_1434749417686_22284 SIZE=1>
<FONT id=yiv3895412105yui_3_16_0_1_1434749417686_22280 size=2
face=Arial><B><SPAN style="FONT-WEIGHT: bold">From:</SPAN></B> via
Personal_Submersibles <personal_submersibles@psubs.org><BR
clear=none><B id=yiv3895412105yui_3_16_0_1_1434762674281_11824><SPAN
id=yiv3895412105yui_3_16_0_1_1434762674281_11823
style="FONT-WEIGHT: bold">To:</SPAN></B> personal_submersibles@psubs.org
<BR clear=none><B><SPAN style="FONT-WEIGHT: bold">Sent:</SPAN></B>
Saturday, June 20, 2015 7:58 AM<BR clear=none><B><SPAN
style="FONT-WEIGHT: bold">Subject:</SPAN></B> Re: [PSUBS-MAILIST] Over
Pressure Valve<BR clear=none></FONT></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434749417686_22428
class=yiv3895412105y_msg_container><BR clear=none>
<DIV id=yiv3895412105>
<DIV id=yiv3895412105yui_3_16_0_1_1434749417686_22427><FONT
id=yiv3895412105role_document color=#000000 size=2 face=Arial></FONT>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5722><FONT size=3>John,
</FONT><FONT id=yiv3895412105yui_3_16_0_1_1434762674281_5723 size=3>I
hadn't given much thought lately to how the Big Boys handle
it. I've planned to have a small, onboard compressor, but its
purpose is to create under-pressure to seal the domes prior to
diving. It's not large enough to charge the tanks. I'm
depending on a portable compressor dockside or on the support boat for
that. A snorkel would be nice even if it extends just two
feet above the hatch or dome. Looking forward to the update on
your 65-footer at the convention.</FONT></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5724><FONT
size=3></FONT> </DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5726><FONT
id=yiv3895412105yui_3_16_0_1_1434762674281_5725 size=3>Hank, that's
definitely a sweet setup you have on Gamma. The compressor
recharged the tanks much more quickly than I expected. I don't
recall how low you let them get before recharging. I don't expect
to have room onboard, and the heat generated would be something of a
negative in semitropical conditions.</FONT></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5727><FONT
size=3></FONT> </DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5729><FONT
id=yiv3895412105yui_3_16_0_1_1434762674281_5728 size=3>I wish I knew
what the pressure differential was that Captain K. experienced.
Apparently it was small enough that he wasn't aware of it and yet
significant enough to convert his coming tower into a personnel launch
tube. If the air pressure inside your sub rose to 20 psi
or about 1.33 atm, you would reach equal pressure when you got within 11
feet of the surface. Any depth greater than that and the outside
pressure would still be greater than the inside pressure (no OP).
The point being that you would have to have a lot of excess interior
pressure to experience OP at a significant depth. Wouldn't your
ears tell you if you got as high as 20 psi? Monitoring and alarm
systems are a must.</FONT></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5748><FONT
size=3></FONT> </DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5749><FONT
id=yiv3895412105yui_3_16_0_1_1434762674281_8806 size=3>Jim</FONT></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_5750> </DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434749417686_22426> </DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434749417686_22429>Personally I think
an onboard compressor is a much safer option than an over pressure
valve. There are multiple safety benefits to an onboard
compressor, over pressure being the biggy. With a compressor you
can get rid of the pressure without surfacing and trying to control a
perfect ascent. With the OPV you have to surface a bit and let air
out and wait then surface more and wait and so on. You can't just
surface and hope the valve keeps up with the demand. This is more
important for subs with large domes.<BR clear=none>The next benefit to a
compressor is, if you lost all your air, you surface by dropping your
weight. In my case the weight is small and I would also drop the
thruster and tail assembly. Still, not much sub out of the
water. With the compressor, I can open my vent valve in the hatch
and use the compressor to fill the ballast tanks.<BR clear=none>Hank<BR
clear=none>_______________________________________________<BR
clear=none>Personal_Submersibles mailing list<BR
clear=none>Personal_Submersibles@psubs.org<BR
clear=none>http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles<BR
clear=none></DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434749417686_22430> </DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434749417686_22431>
<DIV>In a message dated 6/19/2015 12:35:49 P.M. Central Daylight Time,
personal_submersibles@psubs.org writes:</DIV>
<DIV id=yiv3895412105yui_3_16_0_1_1434762674281_8931
class=yiv3895412105qtdSeparateBR><BR clear=none><BR clear=none></DIV>
<DIV id=yiv3895412105yqt79050 class=yiv3895412105yqt8972714691>
<BLOCKQUOTE id=yiv3895412105yui_3_16_0_1_1434749417686_22432
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
id=yiv3895412105yui_3_16_0_1_1434749417686_22433
style="BACKGROUND-COLOR: transparent" color=#000000 size=2
face=Arial>Hi Jim:<BR clear=none><BR clear=none>On the boat if their
was an positive pressure while submerged at depth we started the air
compressor and charge the air banks. The other option was to raise the
snorkel to equalize before opening the hatch.<BR clear=none><BR
clear=none><BR clear=none>John K.<BR clear=none>(203) 414-1000<BR
clear=none><BR clear=none>Sent from my iPhone<BR clear=none><BR
clear=none>> On Jun 19, 2015, at 3:07 AM, via Personal_Submersibles
<personal_submersibles@psubs.org> wrote:<BR clear=none>> <BR
clear=none>> Jim,<BR clear=none>> <BR clear=none>> 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
clear=none>> <BR clear=none>> Keith T<BR clear=none>> <BR
clear=none>> via Personal_Submersibles
<personal_submersibles@psubs.org> wrote:<BR clear=none>> <BR
clear=none>>> Keith,<BR clear=none>>> <BR
clear=none>>> Sorry, I just got home. I was hoping Alec
and some others with more <BR clear=none>>> experience
than I have would chime in as I see has now happened.
There have <BR clear=none>>> been some good discussions on OP
valves in the past. I think some have <BR
clear=none>>> installed a T (on its side) inside the sub
so the air enters the horizontal <BR clear=none>>>
portion, and any water that comes in goes down to a small trap
or into a tube <BR clear=none>>> that leads to a
reservoir. Others just use a rag to catch the small amount
<BR clear=none>>> of water.<BR clear=none>>> <BR
clear=none>>> Alec, does the OP on the exterior of Snoopy point
downward after it exits <BR clear=none>>> at the top?<BR
clear=none>>> <BR clear=none>>> We've also discussed
having an air pressure gauge or altimeter set to zero <BR
clear=none>>> (1 atm) before diving. If it indicates any
pressure above that level at <BR clear=none>>> anytime
during your dive, you'll know you'll have an over pressure
situation <BR clear=none>>> to deal with as you surface and
you'll have an indication of how severe <BR clear=none>>>
that will be. We've also discussed various things that could
cause an over <BR clear=none>>> pressure condition.<BR
clear=none>>> <BR clear=none>>> Best regards,<BR
clear=none>>> Jim<BR clear=none>>> <BR clear=none>>>
<BR clear=none>>> In a message dated 6/18/2015 7:09:19 P.M.
Central Daylight Time, <BR clear=none>>>
personal_submersibles@psubs.org writes:<BR clear=none>>> <BR
clear=none>>> If it opens when submerged, it is because air is
on the way out, and that <BR clear=none>>> prevents water
from coming in. Its like blowing through your nose <BR
clear=none>>> underwater, your nose is open but if you're
blowing, you don't get water in your <BR clear=none>>>
lungs. <BR clear=none>>> <BR clear=none>>> <BR
clear=none>>> Certainly you do get a little water in if you push
the valve open manually <BR clear=none>>> while submerged,
as a test. Or a few drops if you do so when surfaced to <BR
clear=none>>> equalize, as the valve is all wet. But its nothing
much.<BR clear=none>>> <BR clear=none>>> <BR
clear=none>>> <BR clear=none>>> Best,<BR
clear=none>>> <BR clear=none>>> Alec<BR
clear=none>>> <BR clear=none>>> <BR clear=none>>>
<BR clear=none>>> On Thu, Jun 18, 2015 at 7:19 PM, Ken
Martindale via Personal_Submersibles <BR clear=none>>>
<_personal_submersibles@psubs.org_
(mailto:personal_submersibles@psubs.org) <BR clear=none>>>>
wrote:<BR clear=none>>> <BR clear=none>>> TEST!!!<BR
clear=none>>> <BR clear=none>>> -----Original
Message-----<BR clear=none>>> From: Personal_Submersibles <BR
clear=none>>> [mailto:_personal_submersibles-bounces@psubs.org_
(mailto:personal_submersibles-bounces@psubs.org) ] On Behalf Of
via <BR clear=none>>> Personal_Submersib<BR
clear=none>_______________________________________________<BR
clear=none>Personal_Submersibles mailing list<BR
clear=none>Personal_Submersibles@psubs.org<BR
clear=none>http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles<BR
clear=none></FONT></BLOCKQUOTE></DIV></DIV></DIV></DIV><BR clear=none>
<DIV id=yiv3895412105yqt70545
class=yiv3895412105yqt8972714691>_______________________________________________<BR
clear=none>Personal_Submersibles mailing list<BR clear=none><A
title=mailto:Personal_Submersibles@psubs.org
href="mailto:Personal_Submersibles@psubs.org" shape=rect rel=nofollow
target=_blank ymailto="mailto:Personal_Submersibles@psubs.org"
title-off="">Personal_Submersibles@psubs.org</A><BR clear=none><A
title=http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles"
shape=rect rel=nofollow target=_blank
title-off="">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</A><BR
clear=none></DIV><BR clear=none><BR
clear=none></DIV></DIV></DIV></DIV></DIV><BR clear=none><BR
clear=none>_______________________________________________<BR
clear=none>Personal_Submersibles mailing list<BR
clear=none>Personal_Submersibles@psubs.org<BR
clear=none>http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles<BR
clear=none></BLOCKQUOTE></DIV></DIV></DIV><BR clear=none>
<DIV id=yiv3895412105yqt47121
class=yiv3895412105yqt4288363635>_______________________________________________<BR
clear=none>Personal_Submersibles mailing list<BR clear=none><A
title=mailto:Personal_Submersibles@psubs.org
href="mailto:Personal_Submersibles@psubs.org" shape=rect rel=nofollow
target=_blank ymailto="mailto:Personal_Submersibles@psubs.org"
title-off="">Personal_Submersibles@psubs.org</A><BR clear=none><A
title=http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles"
shape=rect rel=nofollow target=_blank
title-off="">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</A><BR
clear=none></DIV><BR clear=none><BR
clear=none></DIV></DIV></DIV></DIV></DIV><BR clear=none><BR
clear=none>_______________________________________________<BR
clear=none>Personal_Submersibles mailing list<BR
clear=none>Personal_Submersibles@psubs.org<BR
clear=none>http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles<BR
clear=none></BLOCKQUOTE></DIV></DIV></DIV><BR clear=none>
<DIV id=yiv3895412105yqt13720
class=yiv3895412105yqt2788981910>_______________________________________________<BR
clear=none>Personal_Submersibles mailing list<BR clear=none><A
title=mailto:Personal_Submersibles@psubs.org
href="mailto:Personal_Submersibles@psubs.org" shape=rect rel=nofollow
target=_blank ymailto="mailto:Personal_Submersibles@psubs.org"
title-off="">Personal_Submersibles@psubs.org</A><BR clear=none><A
title=http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles"
shape=rect rel=nofollow target=_blank
title-off="">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</A><BR
clear=none></DIV><BR clear=none><BR
clear=none></DIV></DIV></DIV></DIV></DIV><BR clear=none><BR
clear=none>_______________________________________________<BR
clear=none>Personal_Submersibles mailing list<BR
clear=none>Personal_Submersibles@psubs.org<BR
clear=none>http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles<BR
clear=none></BLOCKQUOTE></DIV></DIV></DIV><BR>
<DIV id=yqt63315
class=yqt7069744715>_______________________________________________<BR
clear=none>Personal_Submersibles mailing list<BR clear=none><A
title=mailto:Personal_Submersibles@psubs.org
href="mailto:Personal_Submersibles@psubs.org" shape=rect
ymailto="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</A><BR
clear=none><A
title=http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles"
shape=rect
target=_blank>http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</A><BR
clear=none></DIV><BR><BR></DIV></DIV></DIV></DIV><BR><BR>_______________________________________________<BR>Personal_Submersibles
mailing
list<BR>Personal_Submersibles@psubs.org<BR>http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles<BR></FONT></BLOCKQUOTE></DIV></FONT></BODY></HTML>