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In a message dated 7/2/2009 8:57:12 P.M. Pacific Daylight Time,
brenthartwig@hotmail.com writes:
I'm seriously considering using my side thrusters only in a vertical position, unless there is an emergency, such as I'm in a nasty current, or my stern thrusters are not operable. When in transit I might rotate the side thrusters so there is less hydrodynamic drag on them. Then once at the dive site lock them in the vertical position. Hi Brent. With the electric actuators I'm using to control the position of
the side dive plane/motor mount, I can set the thrusters at vertical, and using
reverse, pull the sub down. The "wing" dive planes in the vertical position act
as "brakes".
They rotate through a 120 degree arc from vertical to angled 30 degrees
down. I expect to use the side thrusters as the primary motors when moving
slowly along observing the bottom through the large main window, while the two
rear thrusters will be used for higher speed travel such as transit through the
water or during survey of a larger open area. I'm looking forward to finding out
how fast the sub will go with all four thrusters at full power, but don't expect
to use that setting very often. Maybe for a high speed chase of a Humboldt squid
( Git a Kraken? ) or to keep up with a whale.
The actuators are operated with a simple "rocker" switch, making the
steering and dive plane controls very compact. Able to fit on a small "controls
box" along with the speed controller dials, and this box will be able to be
moved around inside the sub, and also taken up through the hatch so driving the
sub while standing outside on the deck like maneuvering around in the harbor,
parking at the dock.
The nice thing about using the electric actuators as
positioners for rudders and dive planes is they stay where you set them. The bad
thing is...they stay where you set them. I had originally planned on using
air or hydraulic cylinders for these three controls, with a fail safe mode where
the rudder centers itself, and the dive planes go to vertical if the system
fails.
I traded that option for the simpler controls associated with the electric
actuator approach. No air or hydraulic lines,pumps, valves, tanks, gages,
etc. Just a small electrical thru-hull with the motor wires and actuator
wires, all sealed in with epoxy, and just a rocker switch and forward/reverse
speed dial. Doesn't get much simpler than that. Should a problem develop,
replacement of any of the individual components will take just minutes, and in
the case of a leak at the thru-hull, pull the wires off the spade connectors and
close the ball valve the wires go through. Keeping it simple is one of my
primary design considerations. The fewer parts, the easier to maintain, less
chance of component failure, and actually cheaper to build too!
Frank D.
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