[PSUBS-MAILIST] Gamma needs a diet

Sat May 17 18:58:59 EDT 2014

Hank,
What's the capacity of your MBTs (lbs or liters)?   In Gamma's present 
configuration, how many lbs or liters would you  have to take into your MBTs to 
reach neutral buoyancy with a standard 170  lb (77 kg) pilot (or any other 
convenient reference)?  Yeah, I'm a bit  over 'standard' too.
Jim

In a message dated 5/17/2014 5:35:13 P.M. Central Daylight Time,  
personal_submersibles at psubs.org writes:

Hollow glass microspheres in a (typically) epoxy matrix. The  spheres are 
so small, they're more like a powder (for a deep / dense foam.  Shallower 
foams will incorporate larger spheres). Mix the composite with the  highest 
possible volume fraction of glass to resin. 
Sean

On May 17, 2014 4:09:46 PM MDT, hank pronk via  Personal_Submersibles 
<personal_submersibles at psubs.org> wrote:  
How is syntactic foam made.  I once experimented with 3/4inch plastic water 
line (pex pipe), the stuff we plumb houses with now. I heated the end of a 
piece and it melted shut nicely.  So I planned to make a bunch of pipes with 
both ends melted shut then slide a bundle of them inside a pvc pipe.  Then 
fill the void with poly urethane molding resin.  It would be cheap and 
pretty tough.  Perhaps an experiment is in order, unless there is a better idea 
out there.
Hank

____________________________________

On Fri, 5/16/14, Sean T. Stevenson via Personal_Submersibles 
<personal_submersibles at psubs.org> wrote:

 Subject: Re: [PSUBS-MAILIST] Gamma needs a diet
 To: "Personal Submersibles General Discussion" 
<personal_submersibles at psubs.org>
 Received: Friday, May 16, 2014, 7:12 PM

 There's always the not-so-easy but
 very elegant solution of syntactic
 foam filled hydrodynamic fairings.  Go bigger than you
 need to

accommodate future expansion, and compensate in the meantime
 with keel
 weight.  Would improve stability, too.

 Sean

 On 2014-05-15 18:51, hank pronk via Personal_Submersibles
 wrote:

 Alan,
 That would work but I want to keep the sub clean on the

 outside.  Gamma is very slippery the way it is.  I
 am confident I can shed the weight.  I have been
 weighing all the bits and it looks doable.  I am also
 looking at a winter project for Gamma.  I would like to
 have the arm, and valve and a couple of positioning 
 thrusters on a common chassis, like the DW's.  I could
 reduce the weight of the lead drop weight because the entire
 assembly would be the drop weight.  That also solves
 the weight problem from the batteries.  I would use the
 original drop weight screw to drop the new assembly.

 Hank

____________________________________

 On Thu, 5/15/14, Alan James via Personal_Submersibles

 <personal_submersibles at psubs.org>
 wrote:

  Subject: Re: [PSUBS-MAILIST] Gamma needs a diet
  To: "Personal Submersibles General Discussion"

 <personal_submersibles at psubs.org>

  Received: Thursday, May 15, 2014, 8:17 PM

  Hank,a
  simple solution would be to just have a
  number of floats like Alec's Snoopy.He
  has them in a tube, but if the floats had

 attachment holes

  you couldtether
  them & clip them on or off.Alan

   From: hank pronk via
  Personal_Submersibles
  <personal_submersibles at psubs.org>
   To:
  personal_submersibles at psubs.org

   Sent: Friday,
  May 16, 2014 12:04 PM
   Subject:
  [PSUBS-MAILIST] Gamma needs a diet

  Gamma or the pilot needs to go to Jenny

 Craig.  My new

  AGM batteries weigh 73 lbs each and Gamma has a

 60 to 65 lb

  weight budget, per battery. That means Gamma

 needs to shed

  some lbs before I can take a passenger.  I

 can switch

  to aluminum scuba tanks, not sure the weight

 saving

  there.  I can make an aluminum rudder and a

 few other

  parts also.
  Hank

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