Hi Hugh. The outboards I've used had a cable system where the cable is
wrapped around the steering column and runs to the back of the boat where it
pulls the motor left and right. How does the hydraulics tie into this?
My thought was to use pedals ( like brake pedals from a car)
pushing master cylinders and the fluid transfer would go to the slave
cylinders located out side the sub. The two pedals and corresponding cylinders
will need to be tied together so that when one is pushed to extend, the other
would retract.
The orifices would need to be drilled out to allow faster fluid transfer,
but the pressure needed to push the cylinders would be much less than required
to apply the brakes on a car. It won't take that much "push" to move the
rudders or dive planes. The orifice size will determine how fast the cylinders
extend. I don't think a standard master/slave cylinder set up from a car will
have enough fluid capacity to do the job so I was thinking along the lines of
using off-the-shelf hydraulic cylinders as master cylinders with about a pint
or so of fluid capacity. The exterior/slave cylinders would be much smaller,
maybe with a capacity of a few ounces. With the right linkage at the
pedal, a 4 inch travel of the master cylinder should move the slave
cylinder 4 inches as well, thereby turning the rudders or tilting the dive
planes.
The tie-in between the two systems could be a pressurized reservoir
tank filled with fluid, with a check valve to prevent oil from flowing back
into the tank.
By pushing a pedal, you are transferring fluid from one part
of the system ( master ) to the other ( slave ), but not pushing against
the internal pressure of the system, just against the opposing cylinder and
what ever resistance the rudder or dive plane adds. The reservoir pressure
would be supplied by a scuba tank to keep the water from entering
the system at the slave cylinders, and to keep the system filled with oil
should some leak out at the seals.
All the thru-hulls would need valves so if a leak develops, shut off that
line and motor up to the surface.
What do you think ? Could it work ? Anyway, I'm going to play with it and
see what happens. I should be able to make a simple system on-the-bench to
test what kind of pressure it takes to push the pedals and move the slave
cylinders against a spring or counter weight. For a bench test, I could use
just plastic tubing and jury rigged auto parts ( free is good ! ) to see if
it's even viable. I'll keep the guys posted on what I find out. Frank D.