[PSUBS-MAILIST] Pressure Test

Mon Jul 10 21:18:58 EDT 2017

Tim,
If it makes you feel better, I had to scrap 6 aluminum 80s last year.
Greg C

      From: T Novak via Personal_Submersibles <personal_submersibles at psubs.org>
 To: 'Personal Submersibles General Discussion' <personal_submersibles at psubs.org> 
 Sent: Monday, July 10, 2017 8:27 PM
 Subject: Re: [PSUBS-MAILIST] Pressure Test

Hank,What is the price for those 21x120 composite CNG tanks?  Unrelated: for the first time in my diving history I have a scuba tank that just failed its hydro.  Apparently a minor crack has appeared at the valve neck.  This 12 year old, hardly used, aluminum 80 that came with my sub is now scrap metal, maybe worth $6.  Darn.Tim  From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of hank pronk via Personal_Submersibles
Sent: Monday, July 10, 2017 2:26 PM
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Subject: Re: [PSUBS-MAILIST] Pressure Test  Kieth,What are you up to that you need a cng tank?Hank  On Monday, July 10, 2017 9:13 AM, k6fee via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  Hank,  Thanks for the info, I'll check out Evil Bay and see what I can find.   Keith T       Sent from my Verizon, Samsung Galaxy smartphone  -------- Original message --------From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> Date: 7/10/17 2:48 AM (GMT-08:00) To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> Subject: Re: [PSUBS-MAILIST] Pressure Test   Kieth,There are CNG tanks on Ebay, with some sellers that have lots of tanks that are still in service.  The largest composite CNG tank I have come across is 21 inches OD by 120 inches long.  There is a seller close to Salt Lake City Utah with a pretty big inventory.Hank  On Sunday, July 9, 2017 9:24 PM, k6fee via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  Where are you guy sourcing the CNG tanks? Are larger diameter tanks available?  Keith T       Sent from my Verizon, Samsung Galaxy smartphone  -------- Original message --------From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> Date: 7/9/17 7:49 PM (GMT-08:00) To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> Subject: Re: [PSUBS-MAILIST] Pressure Test   Steve,Greg was referring to steel cng storage tanks that are 48 inch ID spheres 3.25 inches thick. I have also been looking at composite cng type 4 tanks as buoyancy modules.  The tanks would be at full pressure (3,600 psi) Hank  On Sunday, July 9, 2017 8:44 PM, Stephen Fordyce via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  Hi Hank,I was under the impression your CNG spheres are composite/fibre-wrapped?  I presume you're aware that using a model based on metal components wouldn't apply well to composite.  I think I posted about it, but I've done a lot of research and some testing on using composite cylinders underwater and it's potentially a bit scary, especially with salt water.  If anyone is interested I can go into more detail.  Cheers,Steve  On Mon, Jul 10, 2017 at 11:53 AM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
I use the calculator on Psubs written by Alec, it is fabulous because you change the values for different materials.  Hank  On Sunday, July 9, 2017 7:17 PM, james cottrell via Personal_Submersibles <personal_submersibles at psubs. org> wrote:  I still think that a CNG sphere will go way deeper. How did you calculate that?  From: hank pronk via Personal_Submersibles <personal_submersibles at psubs. org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs. org> 
Sent: Sunday, July 9, 2017 4:38 PM
Subject: Re: [PSUBS-MAILIST] Pressure Test  Very true.I do love the idea, but, weight is a real killer, every pound is super critical.  If I go with a 7500 footer then the buoyancy is cheap because I will use CNG tanks, don't tell Sean ;-)   Then it will be awesome to have it rotate, just think you can rotate so the port is pointing down between your feet.Hank  On Sunday, July 9, 2017 2:26 PM, james cottrell via Personal_Submersibles <personal_submersibles at psubs. org> wrote:  Yes....BUT...being able to get out on your own is never a bad thing.  From: hank pronk via Personal_Submersibles <personal_submersibles at psubs. org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs. org> 
Sent: Sunday, July 9, 2017 4:12 PM
Subject: Re: [PSUBS-MAILIST] Pressure Test  Greg,That was my original plan, I think it is a great idea for a shallow diver.  But if your going real deep then chances are it will be lowered into the water from a boat or barge, so need for the swivel.  If I end up being less ambitious, and build an Elementary 7,500 I will do just that.Hank  On Sunday, July 9, 2017 1:57 PM, james cottrell via Personal_Submersibles <personal_submersibles at psubs. org> wrote:  Hank,  I was thinking that it might be possible to mount a sphere within a steel frame that allows it to swivel up and down like a gun turret in a bomber. That way, the forward viewport could be incorporated into the hatch and the hatch/ port could be in the "up" position to get in and out and then in the "down" position during the dive for viewing. All internal components could be mounted on an internal frame that hangs from a bearing so that the pilot is always upright. The main ballast system could be a pair of port/ starboard pontoons.  For a shallow diving sub, the hatch/ port could be a large dome for good viewing. A self draining "sail" could also be added around the hatch/ port. If Darth Vader had a sub it would look like that one!  Greg  
_______________________________________________
Personal_Submersibles mailing list
Personal_Submersibles at psubs.org
http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles

_______________________________________________
Personal_Submersibles mailing list
Personal_Submersibles at psubs.org
http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20170711/6efad727/attachment-0001.html>