<html><head></head><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div id="yui_3_16_0_1_1456353038314_6787"><span id="yui_3_16_0_1_1456353038314_6789">Nuytco create a vacuum on the sub to set the o-ring on the hatch,</span></div><div id="yui_3_16_0_1_1456353038314_6703" dir="ltr"><span id="yui_3_16_0_1_1456353038314_6790">so they would be starting off with negative pressure.</span></div><div id="yui_3_16_0_1_1456353038314_6703" dir="ltr"><span id="yui_3_16_0_1_1456353038314_6791">I wonder if they add air after this? Their ballast add system </span>is reliant </div><div id="yui_3_16_0_1_1456353038314_6703" dir="ltr">on cabin pressure so this issue must be important.</div><div id="yui_3_16_0_1_1456353038314_6703" dir="ltr"> I have heard of "expensive" subs using an external air conditioning</div><div id="yui_3_16_0_1_1456353038314_6703" dir="ltr">system prior to diving & that would counter the temperature differences.</div><div id="yui_3_16_0_1_1456353038314_6703" dir="ltr">Alan</div><div id="yui_3_16_0_1_1456353038314_6703" dir="ltr"><br></div><div class="qtdSeparateBR" id="yui_3_16_0_1_1456353038314_6646"><br><br></div><div class="yahoo_quoted" id="yui_3_16_0_1_1456353038314_6627" style="display: block;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;" id="yui_3_16_0_1_1456353038314_6626"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;" id="yui_3_16_0_1_1456353038314_6625"> <div dir="ltr" id="yui_3_16_0_1_1456353038314_6624"> <font size="2" face="Arial" id="yui_3_16_0_1_1456353038314_6623"> <hr size="1"> <b><span style="font-weight:bold;">From:</span></b> hank pronk via Personal_Submersibles <personal_submersibles@psubs.org><br> <b><span style="font-weight: bold;">To:</span></b> Personal Submersibles General Discussion <personal_submersibles@psubs.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Thursday, February 25, 2016 11:31 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PSUBS-MAILIST] Acceptable cabin pressure swing<br> </font> </div> <div class="y_msg_container" id="yui_3_16_0_1_1456353038314_6907"><br><div id="yiv6980198384"><div id="yui_3_16_0_1_1456353038314_6906"><div style="color:#000;background-color:#fff;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;" id="yui_3_16_0_1_1456353038314_6905"><div id="yiv6980198384yui_3_16_0_1_1456352455644_4424"><span id="yiv6980198384yui_3_16_0_1_1456352455644_4425">When I dive Gamma, I find I have a slight negative pressure for most of the dive as the air shrinks from the cold. The temperature swing is huge from surface to 100 feet. As a rule when I dive for any length of time I balance the sub out to Zero on the altimeter by either turning on the compressor or giving a shot of air before I start to surface. It is pretty easy to keep the sub within 100 feet from set point on the altimeter, and that is my comfort level.</span></div><div id="yiv6980198384yui_3_16_0_1_1456352455644_4424"><span>Hank</span></div> <div class="yiv6980198384qtdSeparateBR" id="yui_3_16_0_1_1456353038314_6972"><br clear="none"><br clear="none"></div><div class="yiv6980198384yahoo_quoted" style="display:block;" id="yui_3_16_0_1_1456353038314_6904"> <div style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;" id="yui_3_16_0_1_1456353038314_6903"> <div style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;" id="yui_3_16_0_1_1456353038314_6902"> <div class="yiv6980198384yqt8315161032" id="yiv6980198384yqt04799"><div dir="ltr" id="yui_3_16_0_1_1456353038314_6901"><font size="2" face="Arial"> On Wednesday, February 24, 2016 2:58 PM, Lasse Schmidt Westrén via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<br clear="none"></font></div> <br clear="none"><br clear="none"> <div class="yiv6980198384y_msg_container" id="yui_3_16_0_1_1456353038314_6914"><div id="yiv6980198384"><div id="yui_3_16_0_1_1456353038314_6913"><div dir="ltr" id="yui_3_16_0_1_1456353038314_6912"><div id="yui_3_16_0_1_1456353038314_6973">Is it possible to correlate the alarm to temperature change in cabin from start of dive? Pressure change might well be over 4 psi if it is hot outside and the water is cold.<br clear="none"><br clear="none"></div>Cheers Lasse<br clear="none"><div id="yui_3_16_0_1_1456353038314_6911"><div class="yiv6980198384gmail_extra" id="yui_3_16_0_1_1456353038314_6910"><br clear="none"><div class="yiv6980198384gmail_quote" id="yui_3_16_0_1_1456353038314_6909">2016-02-24 20:12 GMT+01:00 Jon Wallace via Personal_Submersibles <span dir="ltr" id="yui_3_16_0_1_1456353038314_6975"><<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org" id="yui_3_16_0_1_1456353038314_6974">personal_submersibles@psubs.org</a>></span>:<br clear="none"><div class="yiv6980198384yqt3830611511" id="yiv6980198384yqt84353"><blockquote class="yiv6980198384gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;" id="yui_3_16_0_1_1456353038314_6908"><br clear="none">
I think this is somewhat subjective but what is general consensus on maximum cabin pressure swing (higher/lower) relative to hatch closing at the start of a dive before setting off alarms? My thought is that an alarm should sound well before any point of emergency. I'm considering sounding a warning at 2psi +/- and an alarm at 4psi +/- but I'm not sure if this is too strict.<br clear="none">
<br clear="none">
Jon<br clear="none">
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</blockquote></div></div><br clear="none"><br clear="all"><br clear="none">-- <br clear="none"><div class="yiv6980198384gmail_signature" id="yui_3_16_0_1_1456353038314_6921"><div dir="ltr" id="yui_3_16_0_1_1456353038314_6920"><div id="yui_3_16_0_1_1456353038314_6919"><div dir="ltr" id="yui_3_16_0_1_1456353038314_6918"><div id="yui_3_16_0_1_1456353038314_6917"><div dir="ltr" id="yui_3_16_0_1_1456353038314_6916"><div id="yui_3_16_0_1_1456353038314_6915">Lasse Schmidt Westrén<br clear="none"></div>Upplevelsepresent.se<br clear="none">070-28 32 660<br clear="none"><br clear="none"><span><img height="44" width="149" data-id="0ba0dd41-db20-249e-2c2d-53699945d098"><br clear="none"></span></div><div><span>Upplevelser, events och kryssningar.<br clear="none"></span></div></div></div></div></div></div>
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