Re: [PSUBS-MAILIST] propane tanks revisited

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

Bummer,  I called the manufacturer in Texas and apparently 3 or 4 years ago they changed the standards so that now the wall thickness is only .183"  the grade steel they use is SA 455   and 414   P1

Never mind

Brian

----- Original Message ----- 
From: "Carsten Standfuss" <MerlinSub@t-online.de>
To: <personal_submersibles@psubs.org>
Sent: Friday, April 30, 2004 10:02 AM
Subject: Re: [PSUBS-MAILIST] propane tanks revisited


> Hi Brian.. The small wall tickness is the problem.. 
> ..for a shallow dive depth sub or an ambient sub maybe.. 
> 
> From the archive: 
> 
> What do you thing about the following estimate figures : 
> 
> 1.) Sub with used propane tank hull : 
> 14250 $ and about 100 ft dive deep. 
> 
> 2.) Sub with new propane tank hull : 
> 15100 $ and about 100 ft dive deep. 
> 
> 3.) Sub with custom made shell : 
> 15101 $ and about 1000 ft dive deep.  
> 
> Dive deep versus the Dollars : 
> 
> No.1.) 152 Dollar per feet
> No.2.) 161 Dollar per feet
> No.3.)  16 Dollar per feet... 
> 
> ...
> 
> Hmm - seems you save 3 hours for the longitudinal weld and 4 hours
> for the cycle weld - but you waste 2 hours to cut one endcap from
> the propane tank and give some extra hours for cleaning and 
> sandblasting the old colour away.. .. you have to spent some 
> extra money for more lead you need - because your propane tank 
> shell is so light.. 
> 
> Another point: 
> 
> If you spent money for a good custom made hull - and save 
> maybe money on the other equipment during building your sub 
> - you can later spent additional money to purchase better 
> or additional equipment - and you will get a better sub. 
> 
> If you purchase a cheap propane tank - to save money during 
> construction - later no money, no time and even no better 
> equipment will help to make the sub better. 
> 
> So again - what do you save - really ? 
> 
> see you - Carsten
> 
> > Brian Cox schrieb:
> > 
> > Propane Tank investigation:
> > 
> > I was explaning my design to my diving friend and he mentioned that
> > since my pressure hull is around 28" in diameter that I might consider
> > a propane tank.  I have always discounted the propane tank idea
> > because I felt having to deoderize it wouldn't be worth the effort,
> > but then we discussed buying a brand new one -never been used - from
> > the factory.   I didn't think that would make any difference whether
> > you were buyng a new one from the factory or having one rolled from a
> > fabrication plant  -  but  -  he pointed out that since the propane
> > tanks are mass produced that they are cheaper !  So I called a propane
> > company that I know and sure enough they are a lot cheaper .  For a
> > 250 gal  which is approx 30" X 7'  the cost was $850.00    compared to
> > $2000.00 (a year ago) having it rolled at a fab plant.  I still have
> > to find out the exact specs on the propane tank however,  I'm not sure
> > on the thickness  and I haven't confirmed the grade of steel.
> > 
> > Brian
> 
>