A Simpler Sub

[David Buchner <Buchner@wcta.net>]

Reading the last couple months of posts here, I've started thinking I might
be planning something way too scary for my first attempt, even if I stayed
really shallow. I really don't want to be crushed, much.

Besides, the 200 gallon stainless bulk tank I was planning to use for the
hull would be really, really handy as a 200 gallon water tank for my house.

And I really, really like the idea of NOT having a thing sitting in the
yard which has to way 3/4 of a ton just to sink itself. Wrestling it in and
out of the water, making a special trailer to manage it, figuring out how
to drag it out if something went wrong and it sunk to the bottom -- for
many reasons it would be quite a relief.

So now I'm thinking again about really pared-down, ambient-pressure,
only-partly-dry designs. I'm thinking about some sort of skeletal cagelike
contraption on which to hang weights, batteries, motor, a seat, and a
glassed-in box to stick my head in, open at the bottom.

With this approach, I wouldn't be diving very deep or for very long, so I
could just come up with some simple way (air compressor? snorkel tube and
blower? A bucket?) to change the air in my "bubble" after a dive. So I'm
wondering how to find out -- short of putting my head in a plastic bag and
starting a stopwatch -- how long I can breathe happily out of a volume of
about 9 cubic feet (0.25 m^3), without changing air or scrubbing CO2 or
anything. Any ideas?