Self Steering a Catalina 27
The problem. It wasn't long after we purchased "Corleto", our
Catalina 27 that I discovered three things about sailing her in Puget
Sound. Unless we were just daysailing across the Sound, which is only 4
miles wide in most places, we spent 80% of our sailing time sailing close
hauled. (This is because the waterways are long and narrow and the winds
follow them.) Second, our autopilot has a drift angle of about 20 degrees.
This works fine when motoring, as the autopilot isn't fighting the helm
all the time and it averages out nicely. Sailing close hauled, however,
the course has to be set off the wind an additional 5 to 10 degrees to
keep from luffing when the autopilot drifts to windward. Over the course
of a day, this means that distance to windward made good, is less than
half what it can be by steering manually. The third thing is that when the
wind is really blowing hard, the autopilot can't keep the boat on course
for more than half a minute.
Self steering vanes have always fascinated me, but they do
represent quite an investment for a coastal cruiser and they take up a lot
of space. In the fall of 1997, the challenge of designing a home built
unit suddenly became quite attractive to me. I got every book I could find
on the subject, and started experimenting. My first 8" steering oar had so
much power that it bent the 2" ash arm at 4 knots, yet it had practically
no effect on the steerage of the boat when the main rudder was secured.
This convinced me that I had to use this power to turn the main rudder. I
redesigned the oar to a 3" blade, pivoting at the top with steering lines
to the mid point of the oar led to the tiller through blocks. I made a
vane such that it would rotate the oar when the wind shifted off the set
direction. It actually worked. The only problem was that it swung 90
degrees to correct, oversteering to the extreme. Correcting the oversteer
is not a simple matter and it was only then that I began to understand the
problems in designing a vane system, and gained a new appreciation for the
Sheet to tiller steering became my next passion. Using
the principles from "Self-Steering for Sailing Craft" by John S. Letcher,
I rigged up pulleys and surgical tubing and found it worked quite well for
steering windward. In my trip from Astoria to Port Townsend in 1998, I
brought my gear along and we used to steer Mark's Pearson 30 and it worked
better than either hand steering or autopilot. When we had to motor sail,
we quickly found it would not work at all. For my Puget Sound sailing, the
tacks were too short for it to be practical as it has to be reset on each
tack and with commercial traffic and other recreational boats, it becomes
more trouble than it's worth. In the picture at the right my
brother-in-law keeps watch as we self steer across the Strait of Juan de
Fuca, close hauled in a shifty 10 knot breeze. This is a situation where
sheet to tiller steering works best.
The best solution in most cases I found, was to just lock the helm
and let the boat sail itself. With the sails balanced such that the boat
will stay close hauled with the tiller locked a few degrees to windward.
She will stay close hauled as long as the wind stays relatively steady and
the boat doesn't run through strong cross currents or encounter heavy
swells. Tacking is quite easy using the autopilot. Hitting the "standby"
button locks the helm and it can be fine adjusted using the "P" and "S"
buttons. So when I tack, I have the jib sheet ready and hit the button to
move the tiller about 20 degrees to lee and leave it there. As the boat
comes about, I crank in on the new jib sheet and hit the "auto" button
just as the bow swings on to the new course. By the time I have the jib
sheeted in hard and cleated off and any adjustments made to the main, the
boat is approximately on it's new course and I hit the "standby" button.
I've had lots of fun "racing" other boats while sailing single handed and
eating my lunch. Sailing this way in 15 knots of wind and my working jib,
my tacks show just 65 degrees change in compass heading. This is a huge
improvement over the 110 degrees I used to experience using the autopilot
in automatic mode. I managed to sustain speeds over hull speed sailing
this way if the hull is clean and the wind is sufficient. In heavy
weather, I resort to hand steering to prevent the hull from pounding,
falling off on the crests of large waves.
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