|
Hi Myles.
In overcoming the buoyancy of the hull
you might make an ambient heavy by filling its keel with lead, bricks,
concrete, maybe even sand, anything heavy for ballast.
I've seen pictures where fellows who were taking
their sub out for its first test took a bunch of bricks along and if they
weren't heavy enough, just started loading bricks
into the sub's
bottom until they were heavy enough.
To use the same weight as you said to make a
pressure hull, you have to build interior hull reinforcement rings, have a
thicker pressure hull and also worry about the
roundness of the pressure hull and how much
pressure it will take. You have to worry about leaks and hull penetration
fittings leaking. You have to do an unmanned
pressure test like we have been recently and
presently been discussing in the group's postings.
The ambient design does away with all that by
simply keeping the water out with air pressure. Theoretically the ambient
hull outer walls could be as
thin as a beer can since the pressure inside will
be the same as the pressure outside. Of course you wouldn't want to make one
that thin because it wouldn't be practical,
but it would be possible to do so. There are
fellows here who build pressure hulls all the time, but it is much harder to build a pressure hull than an ambient one. Although
there have been wooden, fiberglass and
epoxy pressure hulls made for 1 atm subs that didn't go very deep,
they still are much harder to build than a
ambient hull.
The main advantage of the ambient hull for scuba
depths diving is that you can make it out of practicall any material and you can
make it in almost any shape you want
and do not have to make it spherical as most
pressure hulls are to maximize resistance against extreme external water
pressure. The main detraction of an ambient design is that
your body will be under the same
pressures as a scuba diver at whatever depth you dive to and have to adhere to
dive tables just like a diver does so you don't get the bends. Also
as you submerge and increase the air pressure
inside your sub to equalize the outside water pressure and keep it out, you have
to pinch you nose and blow to equalize your sinus
cavities just like a diver does as he decends. Also
you cannot exceed safe scuba diving depths so you cannot go nearly as deep as a
1 atm sub can go. But for shallow sub diving
not to exceed a maximun of 130 ft, an ambient
design would be much cheaper and easier to build than a 1 atm sub.
Bill.
|