Re: [PSUBS-MAILIST] No more gel-coat!

["Richard Gordon" <lrrg@wantree.com.au>]

Carl,
        A very coarse grade sand-paper should do the trick pretty well. You
would have to spray some kind of sealant over it afterwards though. Perhaps
a better way to do it, if you're moulding fibre-glass for instance is to
make an impession of the coarse grade sand-paper into your cast and then
apply the fibre-glass. This would leave the coarse surface, but without the
extra added weight of the sand-paper. I'm not sure if that would work, but
it may be worth a try.

As for SSBN's, There are probably a lot of things they should try but
aren't. It would definitely make an SSBN faster, but it might make it
noisier also. Again, I'm not sure. Thanks for the reply!

Rich
----- Original Message -----
From: Carl Kem <dustyut@lasal.net>
To: <personal_submersibles@psubs.org>
Sent: Tuesday, February 27, 2001 3:34 PM
Subject: Re: [PSUBS-MAILIST] No more gel-coat!


> Rich, I don't see why you would be kicked from this list.  As for the
> sandpaper idea, I never thought of it till you mentioned it, and it
> sounds pretty darn good to me.  Maybe they should try that with the
> SSBN's, you think?
> Carl
>
>
> Richard Gordon wrote:
>
> > As I may be getting kicked out of the group soon, I thought I'd better
> > share this last bit of info before I go. It has to do with drag
> > reduction. Gel-coat and similar coatings on your submarine cause what
> > is known as a boundary layer. This a layer of slower moving water
> > against the surface of the vessel. Studies by various groups have
> > shown that haing an extremely rough surface creates microscopic
> > turbulance on the surface, thus breaking-up the boundary layer and
> > reducing drag dramatically. It is for this reason that sharks have
> > such rough skin. Other fish do not have rough skin, because unlike the
> > shark, they use their boundary layer to contribute to their
> > propulsion. They generate the laminar-flow with their whole bodies,
> > whereas the sharks only use their tale. So coat your subs in
> > sand-paper and you'll be okay!! lol Rich
>
> --
> "In times like these, it helps to recall there have always been times
> like these."-Paul Harvey
>
>
>