Hello
everyone,
I would like
to introduce myself. My name is Chip Will. First let me apologize for the
length of this email. Just wanted to give as much info as I could.
I have a
concept for a submersible that has been kicking around my head for a few
years and I am ready to start putting the design down on paper (or on the
computer as it is these days). What need now is some guidance from the souls
that have gone before me.
A little
background on myself, and my abilities. I am a certified Scuba diver (18+
years) and Scuba Instructor. I have very good mechanical skills, which
include some machine work, welding, and excellent electrical (low voltage) skills. My shop is set
up with a small mill and lathe as well as gas and MIG welder and about every
tool Sears/Craftman sells (my wife hates that part).
The whole
idea behind this sub is to ?fly? underwater. This will be a purely sport sub
with only fun in mind. I live on Monterey Bay in California. We have some of
the most beautiful cold water diving in the world. I have always wanted to
be able to fly through the kelp forests.
My concept
is for a one person, 1 to 1.5 ATM (I?ll explain this one in a minute)
submersible. It will have a max depth of approx 100-130 ft. It will have a
streamlined hull with the pilot sitting in a reclining position with their
head under a streamlined canopy. 4 thrusters mounted two per side, one
forward and one back will provide propulsion. The thrusters will be able to
rotate on the horizontal (pitch) axis. Two levers on either side of the
pilot control the pitch, sort of like a tank control. Pushing the right
lever forward will pitch one or both (selectable) right side thrusters down,
pulling back will pitch them up. The same with the left lever controlling
the left thrusters. The sub will be adjusted manually through valves to
neutral or slightly negative buoyancy at the surface before the dive. Depth
control will be achieved by use of inverted ?wings? or air foils, as in the
Deep Flight subs. The wings will be mounted on the thruster rotation shafts
and rotate with the thrusters. I have not decided if they will be inboard or
outboard of the thrusters. Foot pedals will control rudders.
I do not
want to have to deal with CO2 scrubbers or any O2 replenishment. I have a
fear of using pure O2 in a sealed environment with any electrical equipment.
I don?t want the headaches of regulating it. I plan on using air from two
scuba tanks, one with a standard scuba regulator for emergency, and one to
replenish air supply. I have an initial concept of a control system that
maintains the air pressure in the sub at about 1.5 ATM. A control board
would allow air to flow from the scuba tank at a set pressure of about 7 PSI
at preset intervals. I will have to calculate the interval once I know the
hull volume. To keep the pressure in the sub from getting to high, the same
board will control a high volume air pump to discharge some of the air in
the sub externally through a series of check valves. As fresh air is
discharged into the hull interior at the front, stale air will be pumped out
the rear. This way I can maintain the pressure at roughly 1.5 ATM. That is
the equivalent of about 16.5 FSW. Most scuba table don?t even recognize that
shallow of a depth as a risk for Nitrogen Absorption. I will have a dive
computer onboard to watch for decompression issues. I don?t see most dives
going for more than an hour or two at most.
That should
give you a general idea of what I want to accomplish. There are two things I
need advise on at this stage before I go any further. First is hull
material. I have read a lot of opinions and seen all the hull calculation
tables. Simple math tells me that if I want a max depth of 130 FSW, I need
to withstand absolute ATM pressure of about 72 PSI on the hull. Add in a 2X
safety factor (250 FSW) and the pressure increases to 130 PSI. My initial
thought was going with a steel hull.
Good strength but heavy and hard to get the real streamlined hull I
would like. A second thought was Fiberglass. If I can build a wood frame
(strictly hardwoods) with stringers going several directions for strength,
with multiple fiberglass layers up to 3/8? ? ½? thick. That seems to me it
would with stand the pressures at shallow depths. Fiberglas would allow me
to work with the more streamlined shapes I have in mind. I would not do any
of this of course without doing all the necessary calculations to see that
it was safe. I do plan on putting in an auto safety feature. If at any point
the depth exceeds a preset limit (probably 150 FSW) a sensor will trigger a
valve to inflate an adequate size lift bag that will automatically deploy
and bring the sub to the surface.
So?. My
first question is:
Should
fiberglass even be considered as hull material?
My second
question is:
What does
anyone think about the air replenishment idea?
Sorry for
the length of this email. I figured it would save time on emailing questions
and answers back and forth if I put as much info as I could in the first
email.
Chip
Will