Re: [PSUBS-MAILIST] hatch rings

["Dan H." <jmachine@adelphia.net>]

Brian,

Your hatch cover being stainless isn't as important as the hatch ring it
mates to.  Your most likely going to be placing your O-ring groove in the
hatch cover and it will stay there.  You can make that part out of carbon
steel and paint it.  True, stainless would be better, but as you mentioned
it's pricey.  Your $156 dollar ring would be over $400 in stainless.

The mating ring, conning tower top, is much better in stainless since it's
what your going to be stepping on and dragging things in and out over.
Paint will get scratched there and cause you problems.  Also the O-ring has
to make a good seal on it every time you close the hatch.

If your watching you budget, stay with the carbon steel ring you have
already ordered but do order a stainless ring for the top of your conning
tower.  One note, when machining the O-ring groove don't forget to allow a
few thousants on each surface for paint build up.

Dan H.
----- Original Message -----
From: "Brian Cox" <ojaibees@ojai.net>
To: <personal_submersibles@psubs.org>
Sent: Thursday, April 08, 2004 12:34 AM
Subject: Re: [PSUBS-MAILIST] hatch rings


> I think I may have made an error when designing this hatch.  My plan was
to build just the hatch and then seal off the bottom part and then take off
our coast here and drop it down to about 1200' or( 365 meters) to see if it
would hold together.  I'm mainly curious about the acrylic dounut.
Origionally I was thinking that the whole assembly would be the hatch but
upon further thought that seemed like it would be too heavy to handle so I
decided to split the hatch above the acrylic dounut so just the top steel
hemisphere would open.  This is the drawing I posted a while back
http://www.prismnet.com/~moki/20040309.103505/hatchXdrawing.jpg  .  The
bummer part is that I just ordered a ring 24" OD by 20" ID and .75 thick
A516 - 70  which I was planning to weld onto the 20" (508mm) hemisphere.
Since when that ring gets welded onto the hemisphere there is going to be a
lot of warping of the ring and it will have to be machined flat so it seems
like you would need enough metal so!
>   that once you're done machining it is still thick enough to be strong.
If I had to use stainless steel for that ring I bet that would be really
expensive.  The 24" od  by  20" id  by .75" thick is going to run me $156.00
would it be possible to weld a piece of 1/4" stainless onto the thicker
piece or would you still have the problem of warping ?
>
> Brian
> ----- Original Message -----
> From: "Carsten Standfuss" <MerlinSub@t-online.de>
> To: <personal_submersibles@psubs.org>
> Sent: Wednesday, April 07, 2004 2:06 PM
> Subject: Re: [PSUBS-MAILIST] hatch rings
>
>
> > I would say: Yes.
> >
> > In the year 2004 hatches rings and troughull connetors should be made
> > from stainless steel. Corrosion on this parts can be really expensive
> > over the years. Maintance time is also an issue.
> >
> > regards Carsten
> >
> > > Brian Cox schrieb:
> > >
> > > Do the hatch rings need to be stainless
> >
> >
>
>
>