[PSUBS-MAILIST] Pressure Test

Tue Jul 4 09:25:43 EDT 2017

Hi Hank,
I think that both you and Sean are partially correct but it depends on the application. Sean's statement that the hull needs to be designed as if the acrylic were not that there depends on the design depth and the percentage of hull that is comprised of acrylic. For instance, if the acrylic is port is increased in size (such as a large dome) then it certainly is functioning as part of the hull and is carrying load. Ron's comment was in the context of a hull designed to go way deeper that acrylic can withstand in most geometries. In his case, the acrylic is not able to transfer much of the load and it falls to the steel to compensate.
Sometimes the opposite is true- sometimes it is the insert that is TOO strong. I once fabricated some acrylic parts for the Johnson Sea Link II and noticed that the guys at HB had added a nylon ring around the aluminum hatch (in between the aluminum and the acrylic). Turns out that the aluminum did not compress at the same rate as the acrylic hull and was throwing the whole thing out of round at depth. The solution was to add a nylon donut "compression joint" to make up for the hard aluminum. The soft nylon compressed to compensate for the harder aluminum.
In theory, all parts of a pressure hull need to compress at the same rate. At full depth, the hull needs to be a scale model of itself at the surface. The trick to creating the correct geometry will depend on the performance of each material at that specific depth and in concert with all other parts of the hull.
Greg

      From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Monday, July 3, 2017 8:39 PM
 Subject: Re: [PSUBS-MAILIST] Pressure Test

Greg,I am having trouble understanding why Ron says you need a hell of a lot more material that 100% rule for a window opening.  My logic is as follows, if you remove a conical section out of a heavy wall sphere and the angle intersects the centre of the sphere, you can glue it back in and the hull has not lost strength in that area.  Now if you replace that with an identical section of acrylic, it will not work.  To my mind the reason it will not work is, the acrylic will compress and the mass is no longer sufficient to carry the load along the load path into the hull.  Now, if the acrylic is thicker, it will handle the pressure without failing and it can compress and have enough strength  to carry the load to the frame .  The window port frame need only transfer the force from the extra thickness into the load path.  In short, to me, the port frame is only supporting the extra acrylic thickness and transferring the force into the hull.  Hank 

    On Monday, June 26, 2017 6:58 PM, james cottrell via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Here is a pic of Ron piloting the sub at 850 meters.http://ocean-innovations.net/OceanInnovationsNEW/Global%20Ocean%20Design/ont_part3_god.pdf

Ron told me that the rule about replacing the same amount of material removed from the viewport opening was wrong -"you need a hell of a lot more" were his exact words. He also used a different steel for the hatch (300 M). He said that the best lube for the port was a "dry glide" spray from  CRC. Contrary to popular thinking, vacuum or silcone grease stores up pressure and then releases it with a BANG! He really knows his stuff...
There are a few good drawings of the DSC hull online and they might come in handy since you will be building something very similar.
Greg

      From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Monday, June 26, 2017 8:28 PM
 Subject: Re: [PSUBS-MAILIST] Pressure Test

Greg,Being a non engineer, I am a copy cat, that is how I built Elementary 3000, I listened to what Sean had to say, I studied Scotts P6 and even duplicated Scott's P6 port and frame.  You could take my port and fit it in Scotts sub.  I stole the port in the Hatch Idea.  The only idea I have had is to glue and bolt the whole thing together.  Trieste has a second sphere from new and it is made from 3 perfectly  machined sections.Hank 

    On Monday, June 26, 2017 5:56 PM, james cottrell via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 I had the pleasure of meeting him at Nat Geo when Jim C was there with the sub and gave a talk. Ron is THE MAN! Probably the most knowledgeable DEEP sub builder today. If you're serious about Titanic, find out EVERYTHING you can about the way he put that sub together.One thing he told me was never used silicone grease on a viewport and added that  "it is the worst". Through testing, Ron discovered that a lot of accepted standards and practices about deep sub construction are actually not correct.
Greg

      From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Monday, June 26, 2017 7:32 PM
 Subject: Re: [PSUBS-MAILIST] Pressure Test

Greg,Do you know Ron personally, were you involved with the port?Hank 

    On Monday, June 26, 2017 4:25 PM, james cottrell via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Hank,
The steel that Ron choice was actually much stronger than HY-100. Here is an article you might find interesting-
http://www.ansys.com/-/media/Ansys/corporate/resourcelibrary/article/AA-V6-I3-Deep-Dive.pdf

Greg

      From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Monday, June 26, 2017 5:57 PM
 Subject: Re: [PSUBS-MAILIST] Pressure Test

Greg,Thank you for the acrylic offer, that would be great, of coarse I will be looking to you for annealing.  The CNG sphere at 48 in ID and 3.25 in thick  could do it but it would be past the safe woking pressure witch is 4444.8 psi just shy of 10,000 feetThe sphere your talking about was probably exotic steel like HY-100Edmonton Exchanger did say they would press a HY steel head for me but foam is cheaper I think.Pity about the CNG sphere because they have a life of 300 years and I can pick one up in Texas for 8KHank 

    On Monday, June 26, 2017 3:20 PM, james cottrell via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Hank,
I'm surprised to hear you say that the CNG sphere is too light. My "seat of the pants" engineering tells me that a CNG sphere would be plenty. Are you sure its too light? If memory serves me correctly, the sphere that Ron Allum made was 42" OD x 2.5" thick gun barrel steel and had a 1.4/1 safety factor at 38,000 ft.
What thickness acrylic do you need for the port? I'll donate a piece of 4" to the cause if that will help.
Greg

      From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Monday, June 26, 2017 4:10 PM
 Subject: Re: [PSUBS-MAILIST] Pressure Test

Greg, I do not have a plan for getting on site.  I have a plan to get there, East Coast that is.  I can haul it cross country myself.Right now it is a dream really, not a plan.  But Elementary 3000 started that way.  I do have it mostly figured out, and I have an EFA guy lined up through Karl Stanley.   I will have two heads pressed and machined at Edmonton Exchanger in Edmonton Alberta.  My original CNG sphere plan is to light.  I think the getting on site part will evolve, I am sure money will make that happen easily.Thanks' for calling it "interesting" and not ridiculous. ;-)Hank 

    On Monday, June 26, 2017 12:01 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Thanks David,I get 7000 lumens. Have a dimmer control for it buthaven't tried it yet.Alan

Sent from my iPad
On 27/06/2017, at 3:08 AM, David Colombo via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Hi Alan, Looks great!, what Lumens did you get with this design?

Best Regards,
David Colombo

804 College Ave
Santa Rosa, CA. 95404
(707) 536-1424
www.SeaQuestor.com

On Mon, Jun 26, 2017 at 4:48 AM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Alan,That really turned out nice, how did you mould the polyurethane? that stuff sticks like mad. I would leave the white gasket, it looks fine.  Either the gasket thickness is not even or the seat is not perfectly matched to the Lenz. 

    On Sunday, June 25, 2017 10:30 PM, Alan via Personal_Submersibles <personal_submersibles at psubs. org> wrote:

 Pressure tested my light to 1000 psi for an hour using the water blaster 
& no leaks! I didn't have a pressure relief valve in the system as I do with
my air pressure set up & it was a pain getting the chamber lid off. I had
thought the water blaster would have leaked a bit of pressure but it didn't.
The sealing system for the wires was a 3 layered process; encapsulating the
wires in the epoxy, then coating the insulation for an inch up from where they came 
out of  the epoxy, & over the epoxy with a 2 part heat activated pvc glue that 
they use on inflatable boats. This glue worked a lot better on the pvc insulation
than several others I tried like E61000 (supposed to be better than shoe goo),
3M 5200 & polyurethane.
Over this, to tidy it up & act as a cable support, I moulded polyurethane.
In the attached photos the white ptfe gasket that the lens sits on looks wet
but it is just the compression of the lens against the gasket. I don't like this
from a cosmetic point & may change it. The 2 objects with the light are the
male mould for the polyurethane cable support & the silicone mould for the 
same.
Alan

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