Re: [PSUBS-MAILIST] Odd Idea

["samdatl" <samdatl@avana.net>]

Maybe I should have gone a little more in depth. You have 2 tanks a and b
there is a nozzle in each tank and each compartment, at the nozzle a,b and
hi pressure air is mixed to create the foam the foam would harden at the
nozzle when all three combine. clean up would be easy with a solvent and the
system is only deployed in the dire emergency that the sub has become so
negatively buoyant that it cannot reach the surface.

Walker
Woodstock, Ga.
samdatl@avana.net
----- Original Message -----
From: "Gary R. Boucher" <protek@shreve.net>
To: <personal_submersibles@psubs.org>
Sent: Saturday, August 19, 2000 3:17 AM
Subject: Re: [PSUBS-MAILIST] Odd Idea


>      The type of foam described would collapse upon the application of
> pressure.  There is a type of foam that will not collapse loosing its
> buoyancy even at much greater depths than most psubs will go.  Syntactic
> foam uses glass bubbles, usually made by 3M company.  These bubbles are
> held in a matrix of epoxy resin.  Most deep applications require the foam
> to be mixed in a vacuum.  If any air pockets are present the foam can
> collapse.  For greater depth applications you can actually attempt to mix
> in some air in the process of combining the two-part system.  You can get
> well over 30 pounds/square foot of buoyancy.
>      Filling compartments in submarines would be impractical.  You would
> need a hammer and chisel to do maintaince.
>
> GB
>
>
> At 11:40 AM 8/18/00 , you wrote:
>
> >----- Original Message -----
> >From: <gregc02@ibm.net>
> >To: <personal_submersibles@psubs.org>
> >Sent: Saturday, August 19, 2000 4:03 AM
> >Subject: Re: [PSUBS-MAILIST] Odd Idea
> >
> >
> > > The thing with submarines is that you WANT to be able to lose
> > > your positive buoyancy to submerge and then refill your ballast
> > > tanks with air to regain your positive buoyancy to surface. Foam in
> > > small fishing boats is a good idea to prevent sinking the boat
> > > completely but with subs you WANT to be able to sink. (Hopefully
> > > temporarily)
> > >
> > > From:           "samdatl" <samdatl@avana.net>
> > > To:             <personal_submersibles@psubs.org>
> > > Subject:        [PSUBS-MAILIST] Odd Idea
> > > Date sent:      Fri, 18 Aug 2000 06:39:50 -0400
> > > Send reply to:  personal_submersibles@psubs.org
> > >
> > > > Wonder if anyone has ever thought up a system that injects 2 part
> >maximum
> > > > expanding foam into compartments and ballast tanks. Seems to me it
would
> > > > work weighs alot less than sea water. and would keep boats from
gouing
> > > > down from too much weight. Just and idea any feedback welcome.
> > > >
> > > >
> > > > Walker
> > > > Woodstock, Ga.
> > > > samdatl@avana.net
> >
> >I think what Walker describes is meant as an emergency measure: to keep a
> >stricken sub from sinking, or raise it once sunk; am I right?  In that
> >context, I can see where it could have some value: but I wonder what
> >limiting effects depth pressure might have on the expansion capabilities
of
> >the foam?
> >
> >VBR,
> >
> >Pat