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