This is probably the 4th most important thing on the
boat. The first three being: 1) hull integrity, 2)
ability to steer, and 3) a means of propulsion. We use
the autopilot about 98% of the time when on passage. I
occasionally hand steer to make sure that the boat is
reasonably balanced without too much helm, but I can
usually tell this just by looking at the angle of the
wheel while the autopilot is steering. And if we find
ourselves “racing” another boat, we both enjoy steering
by hand. But day in and day out the autopilot is the 3rd
crew member.
The general setup is a course
computer connected to the Furuno MFD/8 set to steer
to our next waypoint. There have been times when we
had problems with the interface and would set the
autopilot to steer to a compass heading, but it’s
amazing how fast the cross track error piles up.
Nonetheless, there are times when our desired course
is DDW and due to the wind or sea state we choose to
gybe down the course so we’ll set the autopilot to
steer to a compass heading and then gybe when our
cross track error reaches a certain amount (e.g., 2
miles).
Because we are so dependent on
the autopilot, we have two. The second course
computer is tucked away in a drawer where we hope it
will survive a lighting strike, ready for
installation if the primary computer fails. The
autopilot has a dedicated heading sensor, as does
the Furuno radar. But in a pinch, we can cross wire
them to work with the other so their respective
heading sensors are each other’s backup heading
sensor. And a third heading sensor is in the drawer
with the spare course computer. Then we have two
linear drive units, the rams which actually turn the
rudder, each with its own hydraulic pump. Only one
ram is connected to the rudder quadrant at a time,
but if necessary, we can disconnect one and connect
the other while at sea (as we learned halfway
between Bermuda and the BVIs). The pumps are wired
through a switch which enables selection of either
pump/ram combination without any rewiring. And this
switch also reverses the polarity so that the ram
will push/pulll in the correct direction without
having to tell the course computer that we made the
change.
Our first season we used a Furuno course computer with a
pair of AccuSteer linear hydraulic drive units. In short,
that was not a good solution. The Furuno autopilot would
not hold course, particularly off the wind, and the
AccuSteer drive units failed repeatedly. They were both
replaced over the summer of 2009.
We are now using a Raymarine
SPX30 course computer and Raymarine Type 3 hydraulic
linear drive units. We have an ST6002+ wired
controller and S100 wireless controller. We used a
Raymarine autopilot on our previous boat and were
very happy with its performance and reliability. Our
first SPX30 course computer became erratic and
failed within a few weeks, but the backup is working
fine. Raymarine quickly exchanged the defective
unit.
