Well, let's take a look at my new Cape Horn Integral Self-Steering wind vane.
A wind van steers the boat so the crew doesn't have to. It's not so easy to explain
how they work. It's the wind only. The wind--no electricity involved, just a mechanical apparatus
that steers the boat's rudder.
It does that by sensing which direction the wind is coming from at present. You can see
that the vane is standing straight up and down and it's pointing into the wind like a weather vane.
If the boat deviates from its course, which we can see is pretty straight given the wake behind us,
why then the wind angle on the vane changes. That's all the vane knows--wait! something has
gone wrong, we're off course, I'm going to flop a little bit to one side, as I am now. How that
could keep a boat going in a straight line against the enormous forces of sails, winds
and these four to six foot rolling seas and 25 knots is a mystery, the answer to which
is the pendulum self-steering vane.
The vane is capable only of a tiny signal force--that is,
I can move that easily with my hand
and so can the wind. The genius of this design is that there's also a steering blade in the water.
That's the pendulum steering arm, so called because it can move side to side like a pendulum.
What's moving it from side to side
is the signal provided by the wind vane.
What makes it move is the clever fact that through an apparatus designed in this case by
Yves Gelinas, the designer, manages to transmit that signal force into a rotary force
which subtly changes the angle of the steering blade in the water, and when that angle changes
the enormous force of water going by seven knots forces it to go from side to side.
It doesn't think, it just obeys.
The turning of the blade is so subtle it can hardly be noticed.
But it's like putting your hand out the window of a car, if you turn your palm up your hand flies
upward. This is the hydrodynamic equivalent of that, and the beauty of it is the faster you go
the more force on the steering blade to move it. What happens next is that lateral force, the
pendulum movement side the side of the steering blade, gets transmitted to the inside of the boat.
This design is unique to the Cape Horn gear. It has its own quadrant
installed
by a tube through a three and a half inch hole in the transom of the boat.
Those lines move the steering wheel
as if by magic.
But it's much more mechanical than magic.
Most self-steering vanes just connect the apparatus on the stern to the steering
wheel with a couple of lines around a drum, and that turns the steering wheel and you
can watch it turn the rudder in the normal way. The Cape Horn uses a different approach
Welcome to the world below the cockpit on a typical sailboat.
This is the rudder tube which holds the rudder
which comes up from the bottom of the boat, here, and up into the cockpit above,
where we saw the steering wheel on its pedestal. And this is the ship's quadrant.
The quadrant is a heavy bronze
fitting connected by wires to the steering wheel that allows the turn of the wheel to
make a partial turn of the rudder and thereby control the boat. It uses wires and chains.
What the Cape Horn does is connect this, the ship's quadrant, to its own quadrant
back there on the transom through a series of control lines that are sufficiently daunting in
their complexity, the way they work, as to just about drive me crazy when I was installing it.
In a nutshell,
only parts of the control line move.
This pulls from side to side this pin in the added fastener on the bottom of the quadrant.
That line of force traces this line through a couple of blocks
back to the quadrant.
But it can't be permanently in place or you wouldn't be able
to steer the boat using the steering wheel, so
an extra line continues here,
goes to a turning point on that block, and up to the cockpit.
That exists so that this whole apparatus
can be relieved of its tension and steering manually is possible.
I said it was controversial that all this stuff is below decks--controversial
for me, because it means every day I have to take the gear out and come down here and make
sure nothing's falling apart, which is a routine procedure for everything on a sailboat at sea
but not so routine when everything is so neatly and elegantly hidden where nobody can see it.
Here's how the whole business is engaged and disengaged. These are the two lines we saw
running straight up. They connect to the cockpit. Simply by yanking these forward
and letting this go slackens all the lines.
At that point the boat is entirely steerable by its steering wheel in the usual way. To
re-engage the gear you just grab this here and you yank it back tight and off you go again
Getting in and out of lockers in a seaway once a day, well, it adds to the fun, I suppose.
Why such commitment to daily inspection for all these parts? Well, it's blowing 25 knots.
The wind vane works 24 hours a day without a moment's rest,
the forces on it are fairly enormous.
And not just the forces but the duration,
so things can easily tend to work themselves apart without warning.
Regarding the failure of the belowdecks components that I covered in Inside Single-handed Sailing
(the video), this is the critical Witchard eyebolt, 5/16 inch,
that failed as a result apparently of side forces, and I replaced that
by borrowing the stainless steel padeye that I connect my cockpit tether to. And I used in the
installation about a dozen of these these nice Ronstan blocks, however their shackles can't be
safety-wired closed, and the Loctite I put on them failed. Here's what's elegant about the Cape Horn.
We're looking at it. Most of these devices, including my beloved Sailomat
800, which I gave, sold to a friend who has long distance plans and then wished I'd had it back--
most of them are composed of a big apparatus that bolts on to the stern. The cape horn is elegant
because that's what you see, and it isn't very obtrusive. Another aspect of its value is that
a wind vane puts a drum on the wheel--these are the fittings that it formerly used--which blocks,
and the control lines block one side of the cockpit, which Cape Horn doesn't do--there are
no lines here to oppose passage between the wheel and the rest of the cockpit.
That's the way a vane is supposed to behave,
more or less up and down. If it stays on one side permanently it means that your sails are not
trimmed right and the boat's fighting the helm all the time. It's asking quite a lot of a wind vane
to steer a boat straight through waves, "dead downwind" , as this is called,
and the reason is simply that
the waves that we're sailing over are at a diagonal to the vessel
and as this wave lifts us and we surf
the boat then rolls as a result of the angulation of the waves
and when the boat rolls by its hull form if it rolls that way it wants to turn that way
if it rolls that way the bow just wants to turn that way. The self-steering gear
cannot anticipate that, it can only react to what happens. So there's always a lag.
Bbut still it's miraculous that they do as well as they do under these conditions, because
if I were to take the helm manually
it would be a full-time job to keep this boat going in a straight line downhill. Uh,
as a human being, I'd be able to anticipate the fact that this wave is coming. I would feel the
boat suddenly start to move that way, and I would correct like that and then when it moved
I would correct the other way and then I would correct the other way and then I would correct
as necessary. However. I have to be able to anticipate it. Well,
a wind vane is a mechanical mule. It doesn't think, it just does. So there's always a lag.
Every crew with a wind vane is eternally grateful for it because as I've said so many times,
steering a boat 24 hours a day is a waste of manpower. What a boon it is to have
any pendulum wind vane. They are a gift to single-handers
that cannot be appreciated too much. And it gets really personal with wind vanes.
You sail them more than you sail the boat. You tend to their every need
and every night as you lie your bunk with 30 knots howling through the rigging and black following
seas raising your stern and plunging the bow and as you feel the surf begin, running ever-faster
down the face of the wave behind you that you can't see, waiting for the broach, the inevitable,
occasional turn sideways in which the boat is knocked on its side all the sails start flapping
and you have to get up out of bed and say why am I here? We haven't broached once this voyage.
Thanks, wind vane.