<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Ian, Tim,</div><div id="AppleMailSignature">yes I was thinking about a cam type latch dog as you described.</div><div id="AppleMailSignature">The automatic pressure relief valve that Emile has would automatically</div><div id="AppleMailSignature">reduce any pressure in the hull to the equalisers spring closure pressure,</div><div id="AppleMailSignature">maybe 2psi; then if you forgot to manually press this valve to fully equalise,</div><div id="AppleMailSignature">any internal overpressure would be released as the hatch dog incrementally</div><div id="AppleMailSignature">released the hatch.</div><div id="AppleMailSignature">I guess the only reason for this law is to prevent damage from the hatch </div><div id="AppleMailSignature">opening explosively. Perhaps gas struts would be suitable to stop this!</div><div id="AppleMailSignature">Tim, I have a design for opening from the outside. There could be a grip</div><div id="AppleMailSignature">on the seaward side of the overpressure valve to equalise from outside.</div><div id="AppleMailSignature">I am feeling like I have some solutions now. </div><div id="AppleMailSignature">Thanks, Alan.<br><br>Sent from my iPad</div><div><br>On 31/12/2017, at 11:23 AM, irox via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br><br></div><blockquote type="cite"><div><div style="font-size: 13px;color: rgb(0, 0, 0);font-family: arial, sans-serif;">Although it doesn't have be to the same vent/mechanism as the hatch over pressure safety.<div><br></div><div>Also, there is a requirement for opening the hatch from outside, to add more complications (if you're strictly following regulations).<br><br><blockquote style="padding-left: 5px; margin-left: 0px; border-left: #0000ff 2px solid; font-weight: normal; font-style: normal; text-decoration: none; font-size: 10pt; font-family: arial,sans-serif; color: black;">-----Original Message-----
<br>From: T Novak via Personal_Submersibles <personal_submersibles@psubs.org>
<br>Sent: Dec 30, 2017 1:16 PM
<br>To: 'Personal Submersibles General Discussion' <personal_submersibles@psubs.org>
<br>Subject: Re: [PSUBS-MAILIST] Hatch Closure Mechanism
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</o:idmap></o:shapelayout></xml><zzz![endif]--></zzz![endif]--></zzz!--[if></zzz![endif]--></zzz!--[if></zzzmeta></zzzmeta></zzzhead><zzzbody lang="EN-CA" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Just to add a complication to the project, you will need to have the vent accessible by someone on the outside too, in case the sub has surfaced but the operator is incapacitated.<o:p></o:p></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Tim<o:p></o:p></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p><div><div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in"><p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Personal_Submersibles [<a href="mailto:personal_submersibles-bounces@psubs.org">mailto:personal_submersibles-bounces@psubs.org</a>] <b>On Behalf Of </b>Alan via Personal_Submersibles<br><b>Sent:</b> Saturday, December 30, 2017 12:51 PM<br><b>To:</b> Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br><b>Subject:</b> Re: [PSUBS-MAILIST] Hatch Closure Mechanism<o:p></o:p></span></p></div></div><p class="MsoNormal"><o:p> </o:p></p><div><p class="MsoNormal">Thanks Hank,<o:p></o:p></p></div><div id="AppleMailSignature"><p class="MsoNormal">will have to think on this one. I want to let a novice dive my sub, so<o:p></o:p></p></div><div id="AppleMailSignature"><p class="MsoNormal">the system needs to be bullet proof.<o:p></o:p></p></div><div id="AppleMailSignature"><p class="MsoNormal">If I have some sort of lock mechanism I would need to be able to bypass<o:p></o:p></p></div><div id="AppleMailSignature"><p class="MsoNormal">it if I needed to escape at depth. The pressure at depth would be apposing <o:p></o:p></p></div><div id="AppleMailSignature"><p class="MsoNormal">the manual operation of the overpressure valve. You could flood the sub first<o:p></o:p></p></div><div id="AppleMailSignature"><p class="MsoNormal">but normally the hatch is un-dogged prior to the hull equalizing.<o:p></o:p></p></div><div id="AppleMailSignature"><p class="MsoNormal">Cheers Alan<o:p></o:p></p></div><div id="AppleMailSignature"><p class="MsoNormal"><o:p> </o:p></p></div><div id="AppleMailSignature"><p class="MsoNormal"><br><br>Sent from my iPad<o:p></o:p></p></div><div><p class="MsoNormal" style="margin-bottom:12.0pt"><br>On 31/12/2017, at 1:49 AM, hank pronk via Personal_Submersibles <<a target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<o:p></o:p></p></div><blockquote style="margin-top:5.0pt;margin-bottom:5.0pt"><div><div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif">Alan,<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif">You could have a lock that prevents the hatch mechanism from opening that is activated by turning the hatch vent. I always vent before I one the hatch anyways.<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif">Hank<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif"><o:p> </o:p></span></p></div><div id="yahoo_quoted_4704983245"><div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A">On Friday, December 29, 2017, 11:09:03 PM MST, Alan via Personal_Submersibles <<a target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote: <o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A"><o:p> </o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A"><o:p> </o:p></span></p></div><div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A">Just doing some evening reading of the GL rules & noticed this rule about hatches....<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A">"the closing mechanism is to be designed in such a way that opening of<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A">the hatch is only possible after pressure equalisation" <o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A">I am wondering what options there are for achieving this.<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A">Has anyone had experience of the hatch opening with explosive force due<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A">to internal over-pressure not being equalised.<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A">Alan <o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A"><o:p> </o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A">Sent from my iPad<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A"><o:p> </o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A">_______________________________________________<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A">Personal_Submersibles mailing list<o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A"><a target="_blank" href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><o:p></o:p></span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A"><a target="_blank" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><o:p></o:p></span></p></div></div></div></div></div></div></blockquote><blockquote style="margin-top:5.0pt;margin-bottom:5.0pt"><div><p class="MsoNormal">_______________________________________________<br>Personal_Submersibles mailing list<br><a target="_blank" href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br><a target="_blank" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><o:p></o:p></p></div></blockquote></div></zzzbody></zzzhtml></personal_submersibles@psubs.org></personal_submersibles@psubs.org></blockquote></div></div>
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