Re: HP, weight and visability

[HUNTR2 <HUNTR2@aol.com>]

In a message dated 98-04-25 21:01:29 EDT, you write:

<< 
 At 09:29 PM 4/24/1998 -0700, you wrote:
 >Jon Hylands wrote:
 
 >> On Fri, 24 Apr 1998 19:23:07 -0700, Martin Sanderse
 >> <sanderse@ingenuitygroup.com> wrote:
 >> > One disadvantage of the double hull used for streamlining is that there
 is a lot of mass
 >> > (in this case water) within the total hull envelope that the motors
 have to start and
 >> > stop.  Thsi would imply either a larger motors and props to overcome
 the inertia, or put
 >> > up with sluggishness.
 
 >> Not necessarily. If most of the space between the hulls is filled with
 >> non-compressible foam, then it's not a problem...
 
 >Well, the only way to get the foam or microballons or whatever to sink is
 by adding 
 >weight, so I can restate the case by saying that the lead or hull weight
 you had to add 
 >to get the sub heavy enough to sink the foam  . . . . 
 
 
         Are there any foams or composite materials that are 'heavier' so
 that they act
 as a filler but don't contribute so much buoyancy?
  >>
Unless it's a 1 atmosphere thing, why not just build the hull the shape you
want and let those empty spaces fill with water then... at least you wouldn't
have to haul the weight down the highway.  So we've come full circle on that
discussion.

Another question I have regarding the Vash or Deepwater Flight.  They are not
1atm.  So when you zip from 10 ft to 40 ft and back to 10 ft again in almost
no time, how do you deal with pressure equalization in the inner ear, and
doesn't this violate the diving rules on safe ascent?