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Hi Ian. A reel would need the connection to swivel, and would attach to the
sub in a simple multi-prong electrical through-hull. A possible option
would be a cone shaped cable holder, where the cable spools off, but it would
still need to curl up the cable. Retrieval could be accomplished by rotating the
cone shaped spool. ( simple motor drive )
If the sub was say 200 feet deep, and the cable was 100 feet long, you
could cover an area about 100 feet around the sub, or go deeper with the ROV (
but with less area )
It seems like a fiber-optic cable would be prone to problems. Wouldn't it
work to use coax cable for the video feed?
As for power, I would rather see a battery on the ROV so no heavy power
cables are needed from the sub to the ROV. Just low voltage wires so they could
be cut if needed.
The pressure proof container is the easy part. Just a stout piece of pipe
with a window in the front, camera and battery inside, control panel for motor
drive and dive plane positioning. Make it neutrally buoyant with a drop weight.
It would be small enough so you could make the whole thing from stainless at a
reasonable cost. Something about 24 inches long and 12 inch dia. for the
pressure container would be enough if you packed the stuff inside right.
Some fixed ballast tanks to achieve neutral buoyancy, and with a grabber arm on
the sub, you could make a simple docking mechanism so the ROV could be stowed
away in it's holder after retrieval.
Low voltage solenoids inside the ROV for powering switches so no heavy
cables are needed from the sub.
Seems like an eight pair cable would be enough for the minimum, plus the
coax video feed.
One problem is voltage drop over a long cable, but with the
right solenoids, that would be solved. I had some info on an off-the-shelf video
device that was posted earlier this month here on the psub mail thing. It was
pricey but was a complete system including cable, camera, and monitor. I
think it was built to be deployed from the surface like from a boat or
maybe ice fishing.
The cost of a simple camera( about $150), a small TV monitor (
like the small TV/VCR combo made for a motorhome, 12 volt, $99 at Best
Buy ) and your own pressure cylinder as a start. Then add the motors
and controls, the cable and connections, spooling reel, and various mechanical
things like dive planes and drop weight. Doesn't Steve Pierce have something
like that he's been working on? I think you can buy an off-the-shelf tiny ROV
for about $2500. There's a guy here in Santa Cruz that has one he rents out to
boat owners. I remember seeing an advert on it a while back. Anyway, lots to
think about. Frank D. Gas prices getting you down? Search AOL Autos for fuel-efficient used cars. |