"Johnhh" wrote in
:

I am looking at installing a new bellow deck autopilot on my 34'
sailboat and I'm looking for opinions.

1, Any thoughts on the pros and cons of mechanical linear drives
verses hydraulic linear drives? My understanding is that the
mechanical uses less power and give better feedback to the wheel when
turned off,

Lionheart has a B&G electro-hydraulic autopilot. The ram drives the
bellcrank on the rudder post, directly, and will steer the boat unless the
rudder falls off during complete failure of her steering gear. It is very
powerful and will steer her rudder under just awful conditions. With
inputs from a B&G compass, B&G's Wind instrument and our NMEA network, it
can be steered by compass, like a windvane or by The Cap'n software on the
computer via NMEA 0183 network everything is hooked to.

Unless you are laying right on top of it in the aft cabin of the ketch (39'
Amel Sharki), you can't hear it running. In the cockpit, observing the
wheel, it looks as if a ghost is steering her as there is total silence.
The unit has been zero trouble since it was installed last year.

It draws about 12 amps peak current, but only when the drive motor is
working hard. The motor completely shuts down when the ram stops moving
the rudder and only comes on slowly to move the ram slowly, controlled by
its own computer box located on the boat in the aft passageway. Average
current is much less, depending on sea conditions, of course. Lionheart
has lots of DC power.

Calibration amounts to running the wheel to the port stop, pressing a few
buttons to tell the computer "This is the port stop", then running it to
the starboard stop and pressing the buttons again, then centering the
rudder and pressing the buttons again. Compass calibration amounts to
turning two slow circles out in the harbor until the display tells you it's
calibrated.

The B&G constantly calibrates itself under use, varying its drive
parameters as it "learns" how the boat reacts to rudder input. After a few
hours of use, say making a 90 degree turn, the turn coordination is
perfect, the wheel coming back to center just as the new course is
attained. It's a really nice unit.


2. Raymarine verses Simrad?


I'm just replacing my 3rd Raymarine 2KW radome. The other two were so
cheaply made they all corroded up inside from condensate water. I don't
think we'll be buying more Raymarine gear in the future.....