----- Original Message -----
From: Akins
The three basic types are wetsub, where you wear
full scuba gear and the boat is fully
flooded, 1 atmosphere sub, where the interior is
completely dry and your hull atmosphere
is the same as at the surface, and ambient, which
can be partially wet, or mostly dry.
Ambients are either semi-dry or bone dry. Magical
Child, my Typhoon look-alike, will be as dry as an
Idaho tumbleweed, especially with dessicant.
The wetsub is used basically as a diver propulsion
vehicle
With a proper "windshield", lots of air and batts,
and a dry suit you can tour for miles.
The ambient sub has either openings or a valve to
let the water
pressure into the sub and then that water pressure
is kept out of the sub by superior air
pressurization of the
sub's interior.
Eez no so, Senor . . . well, ok, a semi-dry
ambient is USUALLY open to the surrounding water,
but, doesn't have to be. A semi-dry (Markham boat,
SportSub) uses its cockpit as a variable ballast
tank to control buoyancy. A dry-ambient is
COMPLETELY sealed from the surrounding water. It
has to be or the air compensating regs WILL NOT
WORK. You can admit water into a VBT that is
compensated, as well, but I suggest you keep it out
of the cockpit proper.
The Markham sub uses the inverted cup principle to
keep a bubble of air in the canopy. The SportSub
was initially designed with an electronic sensor
designed by Hugh Daskin of Vancouver that controlled
the water level in the sub. Both were/are open to
the sea.
Magical Child, a true dry-ambient, will be totally
isolated from the ocean. Not only will it serve my
needs as a touring vehicle but it will also be fully
automatic in its depth keeping. I want to look
outside and admire the view, not manage a machine
(obviously I'll be managing depth dynamically)
Your operating depth for an ambient sub can not
exceed normal scuba diving depths.
Por que? As long as you have taken the usual
precautions (and keep your hand away from the hard
ballast jettison handle) a decompression dive is
appropriate. There would have to be an accurate way
of maintaining stops, preferably on an anchor line,
not moving. A sub is just a vehicle. Mixed gases
on the other hand . . .
So the first thing you need to
find out is which of the three types do you want
to build. None are easy.
If you've ever put together a strip-built kayak or
canoe, then a wet or ambient sub isn't much more
complicated. If you're not a diver, haven't used
compasses, depth gauges, pressure gauges,
regulators, BC's, weight belts, or dry suits, then,
yes, putting a dry-ambient together can be
intimidating because you just don't know what the
heck to put into it.
By the way Patrick, an ambient sub does not
require any special type of framing other than for
it to be reasonable sturdy. [snip ] As long as it
is strong enough to hold together and take the
weight of whatever equipment you put on it, it
should be strong enough.
True enough. My dry-ambient will be a monocoque
construction using epoxy over ply. Magical Child
will be used for touring and her hull needs to be
able to handle a rigorous seaway. We get twelve
foot seas out here, and the water can be very
confused with changing wavelengths in a matter of
seconds.
A further note on ruggedness: a semi-dry ambient,
if open to the sea, does not have to have a
particularly strong cockpit. A dry-ambient, on the
other hand, has to have a strong cockpit because of
lag time in the compensating regulators. If you are
plunging in an uncontrolled descent, you need to
give the regs time to respond.
But be aware that an ambient sub will only let you
go to scuba depths
and you have to be a certified diver and follow
dive tables to avoid getting decompression sickness,
and why
bother when you could just go to those depths with
scuba anyway?
Well, I never!!! Bill, Bill, Bill - I want to
TOUR. I've been diving since 1974. I'm tired of
just seeing fish. I want to sit on the deck and
watch the sun go down, see the water rush over the
canopy, cruise through canyons, skim over wrecks,
hover off walls, and look for interesting things
like nude beaches outside of scuba swimming range.
AND, I want to do it dry and comfy - remember my
latte?
It has been pointed out in the past here
that it is almost as much work and trouble to
build an ambient sub as it is a 1 atm sub that can
dive much
deeper. The main difference is that one has a
pressure hull and the other does not. The propulsion
systems are still required by both. Ballast and
buoyancy systems are still required by both.
And exactly what do all those Lloyd's of London
folks do out there - play cricket? A one-atm boat
is orders of magnitude more complex than a strip
built kayak that can sink. Magical Child will
simply be a wooden boat that can indeed sink and
will have a fantastic view. Period. A few basic
instruments and controls. The only pressure type
item will be overpressure valves that will be
installed in the cockpit and cylinder storage areas
in case of either an LP (or HP) line failure or an
uncontrolled ascent. I doubt the exhaust ports on
the regs would be able to dump fast enough.
So there.
Rick L
Vancouver
----- Original Message -----
From: Patrick
To: personal_submersibles@psubs.org
Sent: Tuesday, January 17, 2006 9:12 AM
Subject: Re: [PSUBS-MAILIST] I will build it!
you're kidding me...I can make that with a trip
to Home Despot!
maybe I won't have to wait till I'm older and
wealthier to build a sub afterall!
are there any plans or design guidelines on the
psub site or elsewhere for
this type of vessel?
What should it be framed with?
What would the safe operating depth be?
~suddenly very excited,
-patrick
----- Original Message -----
From: JMDrocks2005@aol.com
To: personal_submersibles@psubs.org
Sent: Monday, January 16, 2006 6:10 PM
Subject: [PSUBS-MAILIST] I will build it!
Hello all, I'm new to the group. I spent 6
years in the US naval submarine service. 4 years 10
months on board the USS Baton Rouge (SSN 689). Now
middle age has me by the b#$%s, and I want to build
a boat of my own. I figure I won't have the
time/money/space for at least 5 years. I count that
as a benefit, as I should have a pretty good plan by
then. in the mean time, I'll learn and share what
little I know.
Jim