<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Jim, Hank,</div><div>I was talking to a sub pilot who had had 10,000 hrs diving various submarines.</div><div>He said they all leak for the first few feet, even the $3 million dollar one he was working</div><div>on. Phil said they pull a vacuum on the Deep Workers before they dive to set the o-rings.</div><div>Maybe that avoids initial leaks.</div><div>Bet Vance could enlighten us here.</div><div>Alan</div><div><br>Sent from my iPad</div><div><br>On 2/09/2013, at 4:57 PM, <a href="mailto:JimToddPsub@aol.com">JimToddPsub@aol.com</a> wrote:<br><br></div><blockquote type="cite"><div>
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<div><font size="3">Hi Hank,</font></div>
<div><font size="3"></font> </div>
<div><font size="3">See if you agree with my line of thinking: At a
hatch depth of 20 feet you'll have about 9 psi differential on your hatch and
your other penetrations as well. At a hatch depth of 1 foot you have
about .445 psi differential.</font></div>
<div><font size="3"></font> </div>
<div><font size="3">For many things, the greater the pressure differential, the
greater the chance of a leak or seepage. However on the hatch in
particular (and possibly on some other things), the greater the
pressure forcing the hatch against the landing, the more tightly it will
seal. So the hatch might seal well at depth, but leak when barely
submerged</font></div>
<div><font size="3"></font> </div>
<div><font size="3">It seems it would be good to do both a high vacuum and
a low vacuum test. If the hatch seals well at high vacuum, but leaks
down at low vacuum, more work is needed on the latches or the mating
surfaces.</font></div>
<div><font size="3"></font> S</div></font></div></blockquote><div><br></div><br><blockquote type="cite"><div><font id="role_document" color="#000000" size="2" face="Arial">
<div><font size="3">Best regards,</font></div>
<div><font size="3">Jim</font></div>
<div> </div>
<div>
<div>In a message dated 9/2/2013 9:21:58 A.M. Central Daylight Time,
<a href="mailto:hanker_20032000@yahoo.ca">hanker_20032000@yahoo.ca</a> 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: 12pt; FONT-FAMILY: tahoma, new york, times, serif; COLOR: #000; BACKGROUND-COLOR: #fff">
<div style="RIGHT: auto"><span style="RIGHT: auto">Hi James,</span></div>
<div style="FONT-SIZE: 16px; FONT-FAMILY: tahoma, new york, times, serif; RIGHT: auto; COLOR: rgb(0,0,0); FONT-STYLE: normal; BACKGROUND-COLOR: transparent"><span style="RIGHT: auto">I always do a vacuum test before my test dives. I
use a compressor as a vacuum pump and draw out as much air as possible.
Then I have a valve on the hull and a vacuum gauge. I let it sit for 24
hr. If it holds the vacuum your set. </span></div>
<div style="FONT-SIZE: 16px; FONT-FAMILY: tahoma, new york, times, serif; RIGHT: auto; COLOR: rgb(0,0,0); FONT-STYLE: normal; BACKGROUND-COLOR: transparent"><span style="RIGHT: auto">Hank<var id="yui-ie-cursor"></var></span></div>
<div style="RIGHT: auto"><br style="RIGHT: auto"></div>
<div style="FONT-SIZE: 12pt; FONT-FAMILY: tahoma, new york, times, serif">
<div style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">
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<div class="hr" contenteditable="false" style="FONT-SIZE: 0px; BORDER-TOP: #ccc 1px solid; HEIGHT: 0px; BORDER-RIGHT: #ccc 1px solid; BORDER-BOTTOM: #ccc 1px solid; PADDING-BOTTOM: 0px; PADDING-TOP: 0px; PADDING-LEFT: 0px; MARGIN: 5px 0px; BORDER-LEFT: #ccc 1px solid; LINE-HEIGHT: 0; PADDING-RIGHT: 0px" readonly="true"></div><font size="2" face="Arial"><b><span style="FONT-WEIGHT: bold">From:</span></b> James Frankland
<<a href="mailto:jamesf@guernseysubmarine.com">jamesf@guernseysubmarine.com</a>><br><b><span style="FONT-WEIGHT: bold">To:</span></b> <a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>
<br><b><span style="FONT-WEIGHT: bold">Sent:</span></b> Monday, September 2,
2013 3:45:27 AM<br><b><span style="FONT-WEIGHT: bold">Subject:</span></b>
[PSUBS-MAILIST] Leak, pressure and life support test<br></font></div>
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<div id="yiv1016670701" style="RIGHT: auto">
<div>Hi All,</div>
<div> </div>
<div>I did some tests at the weekend. Very small pics attached as i
havent updated my site yet.</div>
<div style="RIGHT: auto"> </div>
<div style="RIGHT: auto">First i tested the battery pods and seals with old
inner tubes. Managed to pump them to about 5psi. Not much but i
think it was ok to indicate any leaks. I couldnt see or hear anything
and pressure remained steady.</div>
<div> </div>
<div>Then i did the very sophisticated "saucepan test" over the hatch
viewport. I was just a bit suspicious of this one as it has no gasket,
the lense seats directly to the face. No leak, but agreed, not much test
pressure although the saucepan was full despite the spillage out the
sides.</div>
<div> </div>
<div>Next i did a life support test. I filled and ran the scrubber and
then sat inside for an hour with the hatch sealed. CO2 seemed to level
out at about 5500ppm and i topped up O2 when it got to
19%. </div>
<div> </div>
<div>i also dropped half a psi of internal pressure and that seemed to hold,
so i am hoping the boat is tight.</div>
<div> </div>
<div>I was going to do a leak test in a local fresh water resovoir, but
as im a bit more confident its not going to leak now and its such a logistical
fuss, im going to go straight in the sea. Next week.</div>
<div>Kind Regards</div>
<div>James</div>
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