Hi Jim. At the 2007 convention in Holland, Mi. I saw Dan Brewer's
manipulator arm pick up a golf ball from the lake bottom. He used Bimba air
cylinders filled with oil and it worked like a charm. He has a small hydraulic
pump running the system. I think a hydraulic system is the best suited for a
system exposed to the external pressures and other effects of sea water.
Dan has a large through-hull port about 3 or 4 inch diameter with several
small hydraulic lines and it's a clean and simple design. Maybe Dan could
get in on this thread and explain what it took to put it together. It works,
is simple, clean, and repairable.
On the quick release idea, I can't see how that would be done, but
it's a great idea. I think the big dollar subs have a magnetic coupler for the
tool end of the arm but not sure if the whole arm mechanism can be dropped
with the hydraulic lines and all.
I'm still hoping Vance can give some insight on the "cue ball" method as
this would eliminate a whole host of issues. Any manipulator arm powered by
air/hydraulic/electrics is slow, where the manual "cue ball" arm shown on
the Manta was both nimble and quick. I'll be adding an arm as well but
will wait for the dust to settle on this idea before
committing to the design. The arm itself is pretty easy, just the
means of powering it.
I've been working on a system to move the rudders and dive planes on
my sub that shares some of the same problems.
The criteria I want is set positioning, simplicity and
reliability, leak proof, ability to be valved off at the through hull,
reasonable speed, fail safe return to the unpowered system position, and the
controls inside to be flexible so the control console can be accessed
while seated or standing with the hatch open.
I think I have an idea that covers all of these. I'm thinking of small
electric linear actuators driving hydraulic master cylinders inside the sub,
which in turn drive external hydraulic slave cylinders connected to the
rudders and dive planes. I'd like to avoid using a pump so electrical power
can be saved. A scuba tank should be able to supply the needed pressure to
operate the system at high enough pressure to keep water out, and with
double acting slave cylinders, the need to overcome the pressure differential
between ambient and 1 Atm. is eliminated. Got any thoughts on
this? Frank D.