[PSUBS-MAILIST] Hatch Closure Mechanism

Sun Dec 31 23:19:50 EST 2017

Happy New Year everyone!
Rick

On Sun, Dec 31, 2017 at 2:02 PM Steve McQueen via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Happy new year and thanks for all the sharing and good ideas I have been
> stealing. 2018 just might be the year I have my K250 in the water.
>
> Steve
>
>
>
> *From:* Personal_Submersibles [mailto:
> personal_submersibles-bounces at psubs.org] *On Behalf Of *hank pronk via
> Personal_Submersibles
> *Sent:* Sunday, December 31, 2017 5:42 PM
> *To:* Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org
> >
>
>
> *Subject:* Re: [PSUBS-MAILIST] Hatch Closure Mechanism
>
>
>
> Happy new year, my wife just gave me a drink with an ice cube shaped like
> a submarine lol
>
> Hank
>
>
>
> On Sunday, December 31, 2017, 2:55:46 PM MST, Brian Cox via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
>
>
>
> Happy New year !
>
>
>
> Brian Cox
>
> --- personal_submersibles at psubs.org wrote:
>
> From: via Personal_Submersibles <personal_submersibles at psubs.org>
> To: personal_submersibles at psubs.org
> Subject: Re: [PSUBS-MAILIST] Hatch Closure Mechanism
> Date: Sun, 31 Dec 2017 16:42:13 -0500
>
> In fact, Happy New Year to one and all.
>
> Dive safe.
>
> Vance
>
> -----Original Message-----
> From: via Personal_Submersibles <personal_submersibles at psubs.org>
> To: personal_submersibles <personal_submersibles at psubs.org>
> Sent: Sun, Dec 31, 2017 4:39 pm
> Subject: Re: [PSUBS-MAILIST] Hatch Closure Mechanism
>
> Happy New Year to you, as well.
>
> Vance
>
>
>
> -----Original Message-----
> From: Alan via Personal_Submersibles <personal_submersibles at psubs.org>
> To: Personal Submersibles General Discussion <
> personal_submersibles at psubs.org>
> Sent: Sun, Dec 31, 2017 2:55 pm
> Subject: Re: [PSUBS-MAILIST] Hatch Closure Mechanism
>
> Thanks Vance,
>
> great stuff, Happy New Year.
>
> Alan
>
> Sent from my iPad
>
>
> On 1/01/2018, at 3:30 AM, via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> And speaking of springs, we always terminated each of the MBT blow lines
> (externally) with a check valve. It keeps the lines clear and you don't get
> water backing up to your panel valves at depth. TIP: Use ball type. The
> piston type check valves do an incredibly good impersonation of sustained
> flatulence. It makes the passengers giggle helplessly.
>
> Vance
>
> -----Original Message-----
> From: via Personal_Submersibles <personal_submersibles at psubs.org>
> To: personal_submersibles <personal_submersibles at psubs.org>
> Sent: Sun, Dec 31, 2017 9:19 am
> Subject: Re: [PSUBS-MAILIST] Hatch Closure Mechanism
>
> You are almost always dealing with a vacuum when returning to the surface,
> which in any case you can control over time via the life support system. We
> used a 1/4" ball valve of the HP air bank to equalize. On the Perry boats,
> an external vent line was routed from the penetrator up to the conning
> tower and wrapped in an inverted 'J' over the aft viewport. That way
> venting out cleared the line. There was no over pressurization valve as
> such. We depended on pilots, not springs. I've seen a lot of chatter about
> potential leakage into the cabin from the valves and connections on HP air
> systems at depth. That's what the barometer is for. I've cancelled exactly
> one dive for that, and snugged up a couple of fittings on the job, as it
> were. That's why you always carry tools and a bottle of Snoop. It is also
> why we don't use hardware store fittings. Best quality materials and proper
> installation pays off in the end.
>
> Vance
>
> -----Original Message-----
> From: Alan via Personal_Submersibles <personal_submersibles at psubs.org>
> To: Personal Submersibles General Discussion <
> personal_submersibles at psubs.org>
> Sent: Sun, Dec 31, 2017 12:49 am
> Subject: Re: [PSUBS-MAILIST] Hatch Closure Mechanism
>
> River,
>
> GL also requires an over-pressure valve so I think this is in addition to
> that.
>
> As Steve pointed out, if the closing spring on the over-pressure valve is
>
> 2psi then that is 620 lb. pressure (Steve makes it 1000kg) that the hatch
>
> will still be seeing.
>
> Wonder if Vance has any experience on this?
>
> Alan
>
>
>
> Sent from my iPad
>
>
> On 31/12/2017, at 5:52 PM, River Dolfi via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Ooops, ignore that previous rule. I was reading the Lloyds of London
> rules, not German Lloyds.
>
> "2.1
> The access and exit hatches shall be provided with a closing mechanism
> which makes it possible to create, even when the submersible is surfaced, a
> sufficient contact force on the hatch sealing. Sealing systems for hatch
> covers shall be approved by the Society.
> *In addition the closing mechanism shall be designed in a way that opening
> of the hatch is only possible after pressure equalization has happened, see
> [4*]."
>
>
>
> Of course, now that I think about it, this requirement is redundant. If an
> overpressure valve is installed, there would never be high pressure in the
> cabin to need to relieve. If there is an underpressure, you wouldn't be
> able to open the hatch anyway!
>
>
>
> Thanks,
>
>
>
> -River J. Dolfi
>
> rdolfi7 at gmail.com
>
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