Daniele Fua wrote:
b393capt wrote:
With my a-spinnaker up in 6 knots of breeze I have no problem with
my autopilot, but when I went out yesterday in 15 knots, my
autopilot was not assertive enough to control the boat.

When I set it to keep the 120 degrees off the wind, it completly
failed to do that. Tending to head down, even after the chute
collapsed, it wouldn't return to 120 degrees. If I had not taken
control it would have jibbed.

When instead I set a specific course, it headed up (slowly at first),
not using enough rudder to prevent the boat from heading up and not
reacting at all to puffs that rounded the boat up faster. I repeated
going to standby, turning my boat until about 115 degrees off the
wind, and pressing AUTO again. Each time I repeated this, I
experienced
1. The moment I press auto, she instantly reduces the amount of
rudder I was giving by just a little bit, but enough to cause the
boat to start heading up.
2. The autopilot eventually give more rudder, but reacts too slowly
to prevent us from rounding into the wind.

I have a ST-7001, S1G core pack + added gyro, and auto learn feature.
Since the boat handles so differently under sail, then under motor, I
wonder if the "autolearn" feature has taught itself to not be
aggresive enough.

What's the solution ?


As I understand you use your autopilot with a wind-vane and I am not
even sure that, in this configuration, the signal from the gyro is
used at all. If it is so, you should be aware that the wind-vane is
sensitive to the direction and intensity solely of the "apparent
wind"; it is a well known issue that wind steering has problems when
going downwind due by the "funny" behavior of the vector composition
of the real-wind plus the velocity-wind. Not to mention the wind
disturbance at the vane produced by rolling and yawing which may be
quite important in some situations.
Beside this, as an old timer wind-sailor, I would never rely on an
autopilot under spinnaker especially on a wind higher than, say, 10-12
knots.
So I am afraid that the solution is: under spinnaker, switch off the
autopilot and use a good helmsman... :-)

Regards
Daniel

I've already told him this but he has flatly rejected my contention that
computers can't anticipate, which is what a good helmsman can do! You are
wasting your time on this one.