Re: [PSUBS-MAILIST] hatch rings

["Brian Cox" <ojaibees@ojai.net>]

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
> 
>