<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Pretty much the same as Emile's. I made a disk with lots of holes in it and a spring- loaded cap on the outside. A wing nut inside the sub allows you to adjust the cracking pressure, and "manual override" means pressing on the stem to make the cap on the outside unseat. We're talking just a few hours work to make one of these, it's really simple.</div><div><br></div><div>For those who might not have Kittredge's book, there's a story in there that is relevant. Kittredge had been tooling around for a while on the bottom and there was a very slight air leak in the cabin that he was unaware of. He was about to break surface when there was a big womp and next thing he found himself outside the sub swimming, and the sub on the bottom. The K250 dome had blown out and he'd gone through behind it. It was his only accident. Bottom line... Always have an OP valve and a means of monitoring cabin pressure.</div><div><br></div><div>Best,</div><div><br></div><div>Alec<br><br><div><br></div></div><div><br>On Jan 14, 2015, at 7:25 PM, Brian Cox 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-family:Arial, sans-serif; font-size:10pt;"><div>Alec , what is your over pressure valve?</div><div> </div><div>Brian<br><br>--- <a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a> wrote:<br><br>From: Private via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>To: Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>Subject: Re: [PSUBS-MAILIST] Snorkel<br>Date: Wed, 14 Jan 2015 19:02:45 -0500<br><br></div><div>Hi Sean,</div><div><br></div><div>It's extremely easy to relieve negative pressure... You just press the plunger and can do it with one finger. I do this almost every time before opening the hatch, as a small negative pressure is SOP.</div><div><br></div><div>Best,</div><div><br></div><div>Alec<br><br><div><br></div></div><div><br>On Jan 14, 2015, at 6:57 PM, Sean T Stevenson via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br><br></div><blockquote><div><p dir="ltr">Is it always possible to manually actuate the valve if you have a negative differential pressure? I always presumed that a ball or needle valve would be necessary to equalize pressure on either side of a hatch before opening, because such a valve accommodates pressure differences in either direction. With the overpressure valve, in such a situation you need to overcome this difference in addition to the spring preload. That, or I guess you could just bleed some air or oxygen into the cabin.</p></div>
<p dir="ltr">Sean<br>
<br><br></p><div>On January 14, 2015 12:36:36 PM MST, Alan James via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<blockquote style="margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex; border-left-color: rgb(204, 204, 204); border-left-width: 1px; border-left-style: solid;">
<div style="color: rgb(0, 0, 0); font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);"><div dir="ltr"><span>Brian,</span></div><div dir="ltr"><span>I seem to remember you can manually operate Emile's</span></div><div dir="ltr"><span>overpressure valve; and it is operating procedure to press</span></div><div dir="ltr"><span>it to relieve the remaining pressure before opening the hatch.</span></div><div dir="ltr"><span>If you are looking for an off the shelf solution, make sure</span></div><div dir="ltr"><span>you can do that.</span></div><div dir="ltr"><span>Alan</span></div><br> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div dir="ltr"> </div></div></div></div></blockquote></div><p></p><hr size="1"> <font face="Arial" size="2"> <b><span style="font-weight: bold;">From:</span></b> Brian Cox via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br> <b><span style="font-weight: bold;">To:</span></b> Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> <br> <b><span style="font-weight: bold;">Sent:</span></b> Thursday, January 15, 2015 6:11 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PSUBS-MAILIST] Snorkel<br> </font> <div><br><div><div><div style="font-family: Arial, sans-serif; font-size: 10pt;"><div>I don't see where they list the pressure limit on it.</div><div> </div><div>Brian<br><br>--- <a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a> wrote:<br><br>From: James Frankland via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>To: Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>Subject: Re: [PSUBS-MAILIST] Snorkel<br>Date: Wed, 14 Jan 2015 16:31:56 +0000<br><br></div><div dir="ltr"><div>what about something like
this? I only just googled it so would need research. Don't quote me on it!</div><div> </div><div><a href="http://www.haitima.com.tw/valve/check-valve/check-valve-2026.htm">http://www.haitima.com.tw/valve/check-valve/check-valve-2026.htm</a></div></div><div><br><div>On 14 January 2015 at 15:55, Brian Cox via Personal_Submersibles <span dir="ltr"><<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>></span> wrote:<br><blockquote style="margin: 0px 0px 0px 0.8ex; padding-left: 1ex; border-left-color: rgb(204, 204, 204); border-left-width: 1px; border-left-style: solid;"><div><br><br></div><div><div style="font-family: Arial, sans-serif; font-size: 10pt;"><div>Is there an off the shelf over pressure valve that I can get?</div><div> </div><div>Brian<br><br>--- <a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a> wrote:<br><br>From: James Frankland via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><span><br>To: Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br></span>Subject: Re: [PSUBS-MAILIS!
T]
Snorkel<br>Date: Wed, 14 Jan 2015 13:58:24 +0000<br><br></div><div><div><div dir="ltr">Yes, my OP valve does not have enough holes. I have a job over the winter to add more or drill existing holes bigger. </div><div><br><div>On 14 January 2015 at 13:04, Emile van Essen via Personal_Submersibles <span dir="ltr"><<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>></span> wrote:<br><blockquote style="margin: 0px 0px 0px 0.8ex; padding-left: 1ex; border-left-color: rgb(204, 204, 204); border-left-width: 1px; border-left-style: solid;">Mark, All.<br>
<br>
Mind the area is big enough. The valve in the attachment is designed for a<br>
3000 Kg sub. But even then it is to small if you surface too quick in case<br>
of massive overpressure.<br>
Cracking pressure: 25-75 mBar.<br>
<br>
<br>
Best regards, Emile<br>
<br>
-----Oorspronkelijk bericht-----<br>
Van: Personal_Submersibles [mailto:<a href="mailto:personal_submersibles-bounces@psubs.org">personal_submersibles-bounces@psubs.org</a>]<br>
Namens Mark via Personal_Submersibles<br>
Verzonden: dinsdag 13 januari 2015 13:12<br>
Aan: Personal Submersibles General Discussion<br>
Onderwerp: Re: [PSUBS-MAILIST] Snorkel<br>
<div><div><br>
Since we are discussing over-pressure valves, can you recommend a make and<br>
model, or describe its specifications?<br>
<br>
Regards,<br>
<br>
Mark...<br>
<br>
Sent from iPhone.<br>
<br>
> On Jan 12, 2015, at 7:06 PM, Pete Niedermayr via Personal_Submersibles<br>
<<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br>
><br>
> Scott, I see you have an overpressure valve in place of the snorkel .<br>
Whats that on the other side ?<br>
><br>
> Pete ?<br>
> --------------------------------------------<br>
> On Mon, 1/12/15, via Personal_Submersibles<br>
<<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br>
><br>
> Subject: Re: [PSUBS-MAILIST] Snorkel<br>
> To: "Personal Submersibles General Discussion"<br>
<<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>
> Date: Monday, January 12, 2015, 5:09 PM<br>
><br>
> I<br>
> would recommend a cabin overpressure valve instead. It is a<br>
> mushroom valve. You can see pics on my sub page. Alec<br>
> did the same thing.<br>
><br>
> Thanks,<br>
> Scott Waters<br>
><br>
><br>
> -------- Original<br>
> Message --------<br>
> Subject: [PSUBS-MAILIST] Snorkel<br>
> From: Pete Niedermayr via Personal_Submersibles<br>
> <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>
> Date: Mon, January 12, 2015 3:58 pm<br>
> To: <a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a><br>
><br>
> I have a set of K 350 plans that I'm using as a<br>
> reference for my own design. I'm using the conning tower<br>
> plans pretty much as per. The question I do have is. Snorkel<br>
> or no snorkel ? On the one hand I can see how it would be<br>
> useful have. On the other hand no other design seems to have<br>
> one. What are your opinions? Snorkel or no snorkel?<br>
><br>
> Pete<br>
> _______________________________________________<br>
> Personal_Submersibles mailing list<br>
> <a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br>
> <a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br>
><br>
> -----Inline Attachment Follows-----<br>
><br>
> _______________________________________________<br>
> Personal_Submersibles mailing list<br>
> <a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br>
> <a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br>
> <1399517720.jpg><br>
> _______________________________________________<br>
> Personal_Submersibles mailing list<br>
> <a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br>
> <a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br>
<br>
_______________________________________________<br>
Personal_Submersibles mailing list<br>
<a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br>
<a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br>
</div></div><br>_______________________________________________<br>
Personal_Submersibles mailing list<br>
<a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br>
<a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br>
<br></blockquote></div><br></div>
_______________________________________________
Personal_Submersibles mailing list
<a>Personal_Submersibles@psubs.org</a>
<a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a>
</div></div></div></div><br>_______________________________________________<br>
Personal_Submersibles mailing list<br>
<a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br>
<a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br>
<br></blockquote></div><br></div>
_______________________________________________
Personal_Submersibles mailing list
<a>Personal_Submersibles@psubs.org</a>
<a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a>
</div></div></div><br><div>_______________________________________________<br>Personal_Submersibles mailing list<br><a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br></div><br><br></div> <p style="margin-top: 2.5em; margin-bottom: 1em; border-bottom-color: rgb(0, 0, 0); border-bottom-width: 1px; border-bottom-style: solid;"></p><pre></pre><p></p><hr><br>Personal_Submersibles mailing list<br><a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br></blockquote></div><blockquote><div><span>_______________________________________________</span><br><span>Personal_Submersibles mailing list</span><br><span><a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a></span><br><span><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a></span><br></div></blockquote>_______________________________________________
Personal_Submersibles mailing list
<a href="/eonapps/ft/wm/page/compose?send_to=Personal_Submersibles%40psubs.org">Personal_Submersibles@psubs.org</a>
<a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a>
</div></blockquote><blockquote type="cite"><div><span>_______________________________________________</span><br><span>Personal_Submersibles mailing list</span><br><span><a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a></span><br><span><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a></span><br></div></blockquote></body></html>