[PSUBS-MAILIST] hatch pin

Wed Mar 23 20:05:44 EDT 2016

Brian,In my case the weight alone seals the hatch ;-)   Hey how are you making out, how about some pictures, have you painted your sub?Hank 

    On Wednesday, March 23, 2016 5:57 PM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Hank,             I was just referring to the issue of the hatch wanting to leak right at the surface before there is any pressure on it.  The Dogs should take care of that, unless there is some play there. Brian

--- personal_submersibles at psubs.org wrote:

From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Subject: Re: [PSUBS-MAILIST] hatch pin
Date: Wed, 23 Mar 2016 17:37:51 +0000 (UTC)

I can tighten the hatch with my dogs-same as Gamma.  It is very simple, the dogs are flat pieces ground to a taper and they simply slide under the land ring.  The more they slide the tighter the hatch is.  I can not cinch it metal to metal though from inside.  I can pull a harder vacuum to test the alignment, I was just worried about some equipment inside being damaged from vacuum.   The way it reads to me is that it does not need to be cinched from inside.  It says "hatches are to be designed to seat with pressure"  not by mechanical means.  In the case of a sub with a dome sitting on a Aul ring acting as a hatch-the localized force of a hatch dog could bend the Aul ring if you were to try to cinch it down.Hank 

    On Wednesday, March 23, 2016 10:35 AM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 I seem to remember in some of those old WWII movies ( run silent, run deep) where the are diving ( dive, dive) and they have a line on the inside of the hatch that one guy is hanging on, to hold it down,, presumably until pressure builds up on the outside so it is secured by the pressure alone.  Then maybe they worry about securing the hatch dogs .   Of course they were in a bit of a panic in those situations . Brian 

--- personal_submersibles at psubs.org wrote:

From: "Sean T. Stevenson via Personal_Submersibles" <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Subject: Re: [PSUBS-MAILIST] hatch pin
Date: Tue, 22 Mar 2016 22:49:59 -0600

 I know that this particular rule is often voluntarily disregarded by hobbyists, but just FYI:

 ABS Rules for Building and Classing Underwater Vehicles, Systems and Hyperbaric Facilities (2016)
 Section 11 (Submersibles)
 Subsection 5 (Access Hatches)

 5.3 (Operation):

 "All hatches are to be operable from both internal and external sides.  Hatches should be designed to seat with pressure.  Hatches that unseat with pressure will be considered based on the application of the unit.  The means for opening and closing of hatches should permit operation by a single person under all anticipated operating and emergency conditions.  Hatches are to have means for securing in the open and closed positions.  Means are to be available to ensure that hatches are clear of water before opening.  All hatches are to be considered when evaluating the surface stability of the submersible.  See subsection 11/31."

 5.5 (Pressure Equalization):

 "Means are to be provided for equalizing pressure on each side of a hatch prior to hatch opening.  As an alternative, an absolute pressure indicator with means of adjusting the internal pressure on either side may be provided."

 Technically, to be in compliance you need to be able to cinch it down from the outside too.  Gets to be a complicated mechanism though.

 Sean

 On 2016-03-22 22:07, Brian Cox via Personal_Submersibles wrote:

  Hank, can you cinch it down from the inside ,  obviously you would have to be inside at the time, but you might be able to determine if it is where you want it.   Brian

 _______________________________________________Personal_Submersibles mailing listPersonal_Submersibles at psubs.orghttp://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
_______________________________________________
Personal_Submersibles mailing list
Personal_Submersibles at psubs.org
http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles

   _______________________________________________Personal_Submersibles mailing listPersonal_Submersibles at psubs.orghttp://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
_______________________________________________
Personal_Submersibles mailing list
Personal_Submersibles at psubs.org
http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20160324/09c2da6b/attachment-0001.html>