[PSUBS-MAILIST] dome mount

Thu Apr 23 12:59:48 EDT 2015

James,
Yes, a swinging dome would be awesome.  My big concern though is over pressure with such a large dome.  I am not comfortable relying on an over pressure valve.  I think the over pressure valve needs to be a monster to work.  Think how long it takes to deflate an inner tube at 5 psi.  In a stressful situation you may be tempted to surface fast, with an over pressure you could have a real problem.  I still favour a manual valve in the hatch and the flood valve can be a back up to that.  I guess releasing the hatch is an option also????  not sure about that one.
Hank  --------------------------------------------
On Thu, 4/23/15, James Frankland via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Subject: Re: [PSUBS-MAILIST] dome mount
 To: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
 Received: Thursday, April 23, 2015, 11:24 AM

 Hi
 Hank,You could have made a hatch arrangement so
 you could remove the dome from inside.  Mine is like that
 and I think Emile's as well.   I like the idea of
 having 2 ways out!   But then you have security against
 overpressure.  "Swings and Roundabouts" as they
 say.
 On 23 April 2015 at 13:01,
 hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 wrote:

 Hi James,

 The Alu ring is bolted to the steel ring with 8, 3/8 fine
 thread bolts.  More bolts may have prevented the
 distortion.  The studs cured the problem perfectly. Also
 the dome is secured better in the case of an over
 pressure.   I will change the studs to grade 8.

 Hank--------------------------------------------

 On Thu, 4/23/15, James Frankland via
 Personal_Submersibles <personal_submersibles at psubs.org>
 wrote:

  Subject: Re: [PSUBS-MAILIST] dome mount

  To: "Personal Submersibles General Discussion"
 <personal_submersibles at psubs.org>

  Received: Thursday, April 23, 2015, 4:51 AM

  Hi

  Hank,How was the alu ring attached to the 2"

  reinforcing ring before
 you added the studs?  I think its

  time for some picture updates on your page...

  :) Kind

  RegardsJames

  On 22 April 2015 at 18:07,

  hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>

  wrote:

  Emile,

  I am pulling pretty hard on the straps because the dome
 is

  150 lbs on its own.  Also I am relying on the EPDM to
 seal

  at the surface.  I could have put more bolts in the AL
 ring

  also but this way I don't have to worry about
 pulling

  the treads out of the AL.  I used the AL you suggested
 when

  I asked James.

  Hank--------------------------------------------

  On Wed, 4/22/15, Emile van Essen via
 Personal_Submersibles

  <personal_submersibles at psubs.org>

  wrote:

   Subject: Re: [PSUBS-MAILIST] dome mount

   To: "'Personal Submersibles General

  Discussion'" <personal_submersibles at psubs.org>

   Received: Wednesday, April 22, 2015, 9:26 AM

   Which Alu? Yield varies

   from 100 to 450 N/mm2

   AW 5083 or Anodised

   AW6082 is the best for domerings in my opinion.

   Emile

   -----Oorspronkelijk bericht-----

   Van: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org]

   Namens hank pronk via Personal_Submersibles

   Verzonden: woensdag 22 april 2015 13:50

   Aan: personal_submersibles at psubs.org

   Onderwerp: [PSUBS-MAILIST] dome mount

   I had a design problem with my

   AL dome seat.  I had the strap assembly

   bolted to the AL seat only, and that was a

   mistake.  After installing the

   dome

   assembly on the sub I double checked the fit and
 found

  that

   when I

   tighten the straps the Al seat was

   distorting.  I am not very experienced

   working with large AL material and did not

   realize how Whimpy it is.  I

   corrected this

   by drilling through the AL and into the 2in thick

   reinforcing

   ring and installing studs.  Now

   the strap assembly pulls from the steel

   ring.  I simply tighten the strap assembly

   until I see an even impression in

   the EPDM

   gasket.  I am now reassembling Gamma, I am excited
 to

  get

   back in

   the water and try out my dome.

   Hank

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