[PSUBS-MAILIST] new sub project

Mon May 25 16:09:12 EDT 2015

Hank, I share your interest in driving psubs designs smaller to make them easier to deploy, transport and fabricate. Sg.  Pepper is sill one of my favorite psubs.  I went through many design calcs on a design much like your describe with the ability of a small 1-atm central pressure hull to pivot relative to MBTs pods that remain horizontal while trying to meet constraints of ABS.  What I found is that ABS is not kind to small psubs like this.  I found that it was almost impossible to meet the minimum  GB-CG constraint without using mercury to radially shift CG on the fly which is against ABS rules. The other issue I found problematic is trying to meet the ABS minimum free board rule and the loss of surface stability on these designs if you retain the ability to rotate.  For these micro psubs, excessively tall humans like Sean (ha ha) kill surface stability when you get in and out in an emergency situation on the surface.  I think it is  possibly doable if you ignore ABS freeboard  and mercury rules. In the spirit of KISS, much beloved in Alec's new boat,  I finally gave up on trying to pivot the pressure hull and have been working on a small psub in which the pilot remains vertical and tilted forward but without the ability for the pilot to rotate the boat.  Batteries pods  hung low at the pilots feet generate very nice CG-CB spread  to enhance stability but make it harder to launch with conventional trailer arrangement.  Also without the ability to pivot, much like a scuba diver does is going from a surface orientation to a submerged orientation, visibility becomes an issue unless you live in Roatan.
To me, there is lot of romance to designing and building a 1-atm self contained DIY psub much like the old JIM atmospheric body suits http://en.wikipedia.org/wiki/JIM_suit but it is not going to be easy.  Sean, at one time, I think I remember you being interested in designing a one atm. body suit.  Did you ever make any progress on this?
Hank, at the speed you fabricate stuff, I suspect you will have all this sorted out and a boat in the water by time I finish this email.  Let us know how you come along with the concept.
Cliff

   From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 To: personal_submersibles <personal_submersibles at psubs.org> 
 Sent: Monday, May 25, 2015 3:10 PM
 Subject: Re: [PSUBS-MAILIST] new sub project

| Alec,
Any ideas or criticisms are welcome.
Hank |

     From:  Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org>; 
  To:  Personal Submersibles General Discussion <personal_submersibles at psubs.org>; 
  Subject:  Re: [PSUBS-MAILIST] new sub project 
  Sent:  Mon, May 25, 2015 12:28:28 PM 

| Sounds good, tiny and light is a major plus - particularly as you have a boat that can get you to a dive site and over the side. 
Alec
On Sun, May 24, 2015 at 11:12 PM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Alec,
I am not thinking flyer at all.  The water clarity would not support the speed.  I am thinking of a simple tiny light sub that can launch anywhere even off the deck of my boat.  It is just a though right now.

For now I am enjoying my what seems gigantic bow dome.  The visibility is unbelievable, the modification cost and effort has been well worth it.  As a bonus, my payload is back to 500 lbs plus.  I had to fill the sub with steel plates to get it to sink.  :-)
Hank  --------------------------------------------
On Sun, 5/24/15, Private via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Subject: Re: [PSUBS-MAILIST] new sub project
 To: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
 Received: Sunday, May 24, 2015, 10:38 PM

 Indeed! Except mine went
 vertical only for emergency exit rather than as standard
 procedure.  It was not going to have any freeboard to speak
 of in vertical mode, so you would climb out in a hurry and
 watch her sink from under you. The method of going vertical
 was dropping the emergency weight, which was located at the
 very front. More than the front actually, it stuck out and
 constituted your crash bar. The sub was a "flyer",
 a poor man's Deep Flight. I had her 90% complete when I
 bought Snoopy, and the flyer project sat untouched for many
 years while Snoopy took up all my time and served as a
 classroom. The sub I'm finally finishing up now recycles
 the flyer hull, but redone to be conventional. Well,
 conventional in the sense of having ballast tanks and a
 conning tower - she's actually a pretty bizarre beast as
 the folks who come to the convention will see! My conclusion
 was that a flyer must be great fun but requires both
 unusually clear water and a vessel capable of laun!
  ching the sub at the dive site. If I owned a
 mega yacht and cruised the Galapagos, a flyer would be just
 the thing. But what I'm aiming for now is radical
 simplicity, whereas the old one was all touch screens,
 servos, PLCs, and such.

 Best,

 Alec

 > On May 24, 2015, at 7:31 PM, Jon Wallace
 via Personal_Submersibles <personal_submersibles at psubs.org>
 wrote:
 >
 >
 > Talk to Alec, he was building such a
 design years ago before he acquired SNOOPY and ultimately
 decided against it...but I don't recall why.
 >
 >
 >> On 5/24/2015 6:31 PM, hank pronk via
 Personal_Submersibles wrote:
 >> Yes,
 you float it to the dock side, then tip it vertical to get
 in, close the hatch, tip it horizontal, and your away. 
 Saves building a CT that my 200lb sexy frame can fit into
 :-)
 >>
 Hank--------------------------------------------
 >
 >
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