Re: ambient preference

[Rick Lucertini <empiricus@sprint.ca>]

Nathanael Henderson wrote:

> [snip]        The trouble with dry ambient subs is air consumption.  If you have a
> compartment 2'x2'x7' that's kept dry, that's going to cost you 28 cubic
> feet of air to descend to 33'.  It only takes a few trips to suck a scuba
> tank dry.   SO, it may be worthwhile to try to make it as shape-comforming
> as possible, both to reduce the ammount of air needed to equalize it, and
> to keep bouyancy changes under control (since the smaller air volume can
> be equalized more quickly.

How true.  Hi, Nathanael and All . . .

I guess by now you may have read my responses regarding internal cockpit volumes, air
consumption and buoyancy control in dry ambient boats.  If a kayak sock doesn't ring
a bell, let me know.  I can go over it again.  But, even fisherman's waders, with a
wrap-around skirt stitched and glued around the waist would work.

> Along the lines of safety, be sure to include a drop weight--if 'it'
> happens, getting positively bouyant quick can be a life saver.  The drop
> weight would ideally be enough to make you possitively bouyant even if the
> compartment floods (such as by making the battery/motor assembly
> jettisonable and by keeping some natural positive bouyancy in the design

Hey, you've put a lot of thought into this.  You're right on all counts.

I would like to add that weight should be jettisonable in small quantities to allow a
slow and controlled ascent.

> [snip]        By sticking to ambient pressure, you get a huge ammount of creative
> and design flexibility.

Don't let the one-at guys hear you say that!!!  Of course, you're bang on!
Personally, I love the hull forms you can design around ambient dry boats.  Anything
reasonably hydrodynamic, even a streamlined Star Wars space vehicle.  I'd love to
incorporate some sci-fi into a design.  Look at Graham Hawkes' one-at sub.  It's a
work of art.  No one can tell me his sub's not been influenced by sci-fi.  Look at
Phil's ExoSuit.  Mind you, as one-at's, these are the exceptions to the rule.

> For materials, fiberglass seems to be the most
> popular, although I'd personally go heavily or even exclusively acrylic
> (Plexi-glas.)   Mmmm, see-through sub.  :-)   THIS WILL NOT BE AN
> INEXPENSIVE PROJECT.   Cheaper than a 1 ATM sub certainly, but even the
> cheapest designs will probably run over a grand, and depending on how
> fancy you want to get things can easily run to many times that.

You just struck a chord with me.  I'd thought of approaching the acrylic or
polycarbonate manufacturers to supply the raw materials for a see-thru dry ambient
sub.  Maybe YOUR project, hmmm???

Wow, just like those see-thru engines or see-thru human bodies.

Naw - a real sub could NEVER look like that . . . .   heh heh heh


Rick




--
Rick Lucertini
empiricus@sprint.ca
(Vancouver, Canada)