Hi Jim. I'm considering the electric actuator method of powering the
hydraulics because I want the controls to be electrical. The reason for that
is I want the control console to be portable or moveable inside the sub.
If the rudder control is bolted in a stationary position, I won't be able to
steer the sub unless I'm sitting in the pilot seat. I'd really like to be able
to steer the sub while standing up with my head sticking out of the open hatch
or maybe even sitting on top of the sub. This is mostly for maneuvering in the
harbor or along side a support boat. I may be able to just use the
side thrusters for that. I won't know until I float the sub to see where the
surfaced water line is. The other reason is I don't know if I can get an
electric linear actuator sealed well enough to use it alone and eliminate the
hydraulic cylinders altogether. That would be my choice but again, not
sure I can get it sealed.
With the recirculating method, the pump is running all
the time. That will drain the batteries even when not actuating a cylinder.
The pump is running all the time. I could possibly use a limit switch so the
pump shuts off when a given pressure is achieved, but small adjustments to the
rudder would mean the pump starting and stopping repeatedly. Basically still
running all the time.
I know it seems overly complicated, and another down side is that a two
way hydraulic cylinder needs two hydraulic lines meaning two thru-hulls for
each. Another way is with compressed air. I could use bimba air cylinders to
operate the rudders/dive planes but again, that would make the control console
very bulky with all the wires AND air or hydraulic lines coming out of
it.
The dive plane controls could be stationary, and maybe even the rudders
if the side thrusters are enough to maneuver while surfaced. Still
looking at the whole system and what parts are available off-the -shelf. I
think I'll try getting some parts together and rough up a system on the bench.
Still open to suggestions. Frank D.