Self Steering Gear
vane self steering system is not an essential piece of equipment on a
for anyone who sails alone or cruises short handed over long
the benefits can be immeasurable.
Long tricks at the helm are exhausting, concentration wanes, essentials
eating, trimming sails, navigating, sleeping etc are neglected.
Besides that, with a self-steering system set and the sails trimmed you
have time to relax and really enjoy the ride.
Self Steering Wind Vanes
The first time that a wind vane was
used to cross an ocean it was on a
motorboat, or so I'm told.
however, electronic auto
pilots are much more
reliable at holding a course and the power to drive them is not an
most engines are fitted with alternators which constantly produce
However, a wind vane gear is
best solution for a sailing boat and not just because of the power
Wind direction offshore tends
to remain relatively
constant over long periods, but there are always constant minor
In order to keep the sails
drawing at maximum efficiency,
while maintaining a set autopilot course, they would have to be
Wind vanes on the other hand
will slavishly follow any
wind shifts, a good one will often do it better than most humans and do
hour after hour without tiring.
As well as not requiring any
battery power, the windvane
does not have any complex electronics which, will be vulnerable to damp
that are unlikely to be repairable without spare parts.
Many of the simpler vane gears
can usually be repaired or
rebuilt using non-specific parts and lashings.
And you can even build one by
Prior to the development of
windvanes long distance
sailors such as Joshua Slokum and Eric and Susan Hiscock relied on
boat’s natural ability to bold a course.
Others used systems of blocks
and lines between the sails
and the tiller.
One of the most common used
setups for downwind sailing
was using poled out twin headsails, with the sheets lead back to the
that when the pull on one sail increased, the tug on the tiller would
boat back on course.
These methods required the
sails to be set for balance rather than speed, which is fine for the
However, the increased
interest in long distance short
handed racing prompted the development of vane gears.
In the first Singlehanded
Transatlantic Race in 1960 all
five entrants used vane gear.
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point of a wind vane steering gear is to provide feedback to the rudder
the boat can remain at a set angle to the wind, 'in the groove'.
This will not be a steady
compass course but a
constant point of sail.
First you sail the boat on
the desired compass
Then you trim and balance
the sails for this
Once the boat is trimmed
the vane is set and the gear
engaged to steer the boat on that point of sail.
So how does it work?
There are numerous variations
to the mechanics of the
linkages types of vane etc but they all work on the same basic
The vane is set so that it
feathering when the boat is in her
variation to this angle to the wind will cause the vane to rotate.
The linkages then transmit
this rotation to the rudder in
such a way as to bring the boat back on the desired heading.
With the boat back on its
correct heading the vane and
thus the rudder will return to its original position.
In theory the vane could be
mounted anywhere where the
wind across it is unobstructed.
However it has somehow to be
connected to the rudder by
some form of mechanical linkage, so the most logical position for it is
And it is the linkage which
When the boat drifts off the
wind the vane will rotate or flip with the wind, this movement then
transmitted to the rudder as a turn in the opposite
In the case of a simple
vertically rotating vane, as the
boat turns clockwise away from the wind direction the vane will rotate
anti clockwise direction relative to the boat.
This rotation then needs to be
transmitted to the rudder
to turn it clockwise, relative to the boat, this will then turn the
clockwise until she is back in the groove.
Once set up a vane gear can be
Setting up is however a matter
of getting the balance
Like your sails the wind vane
needs to be set according
to the apparent wind, the sails rudder and vane need to be in
Because the vane is subject to
the apparent wind it will
be less effective on a run and in light airs.
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In the very
simplest of self steering vane gears as the vane pivots the movement is
transmitted via lines directly to the tiller.
On others the vane acts
directly on a secondary
However the force provided by
a wind vane alone is rarely
sufficient to make this system work with large boats.
To overcome this, variations
such as the servo pendulum
system, invented by "Blondie" Hasler have become widespread.
These systems harness the
power derived from the motion
of the boat through the water to help turn the rudder.
This is without
doubt the easiest wind vane
self-steering device to understand and build.
The vane is vertically pivoted
and controls a trim tab on
This can be either the main
rudder or an auxiliary
I had this type of gear on my
previous boat and it took
me far and wide.
It isnâ€™t the most accurate of
gears however with
some judicious use of bungee to dampen any tendency to yaw it served me
Not only is it simple to build
and operate but its very
simplicity gives it an uncomplicated elegance.
When I built the new rudder
it so as to incorporate the vane gear.
This horizontal vane gear also
operates on a trim
However the vertical vane is
set by turning it on its
turret until the vane stands as nearly vertical as possible.
Because it tilts
proportionally to strength as well as
direction of the wind it is a more powerful version of the
And there is less tendency for
the boat to
On the vertical-vane
servo-pendulum invented by Blondie
Hasler, the vertical wind vane is connected to the servo blade.
As the pendulum, or servo
blade, is turned by the vane it
is forced aside by the its movement through the water.
It is this force which is then
transferred to the tiller
or wheel by means of the linkage.
The main advantages are that
the stronger the wind, the
faster the boat speed, the greater is the force is applied to the
The servo-pendulum with a
vertical wind vane has become
the standard for most commercially produced wind vane systems.
While there are differences in
their methods of
transmission, the basic principle is the same.
The most popular among
cruising sailors is the
Monitor because of its rugged construction and
because most parts can
be fabricated and repaired relatively easily.
While these commercially
produced systems are robust,
perform silently and very near flawlessly on all points of sail, they
For more technical information
on the pros and cons of
self-steering see SELF-STEERING UNDER SAIL
Autopilots and Wind-steering
Systems by Peter Christian FÃ¶rthmann.
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Your Own Vane.
The easiest and
expensive type of boat to
fit a wind vane to is one like Mignonne which has
rudder and tiller.
This uses the vane to control
a small trim tab on the
trailing edge of the main rudder.
The trim-tap controls the main
rudder in the same way a
trim-tab works on an aeroplane wing.
As the tab turns in concert
with the vane, the rudder is
deflected in the opposite direction thus turning the boat.
If you are designing your own
vane, whatever the style
there are several details to keep in mind.
The vane must be as
sensitive as possible, which
usually means large and light.
Friction must be kept to a
minimum, preferably with
non corrosive bushing such as Teflon.
The tab needs to be narrow
and deep yet clear of the
bottom of the rudder to avoid damage.
Whatever linkage you use
should not be affected by
movement of the main rudder.
The vane I have used on Mignonne
was inspired by
an idea from one of Lin
and Larry Pardey’s books.
Rather than use the usual
plywood panel I made a wooden
frame to support a sailcloth vane.
My vane like the rest of the
boat is still very much a
work in progress and the present vane really needs to be larger, I
together from off cuts and leftover bit of sailcloth.
However, creating it to look
like a small mizzen sail has
the added advantage of fitting it into the overall look of the boat.
Also the light weight needs
less of a
My main fear from using a
trim-tab was how it would be
affected when motoring astern.
The usual advice is to have a
locking device to center
the tab, but I know from experience how easy it is to forget something
that until it is too late.
So what I have done is attack
the tab with enough
clearance between it and the trailing edge of the rudder to allow it to
through 360 degrees.
This type of trim-tab also
seems to work best where there
is an angle between the axis of the rudder and tab pivots and if the
sited where these cross.
Because the trim-tab turns in
the same direction as the
vane the linkage is direct.
The only provision needed is a
method of allowing the
vane to be set according to the wind direction.
I used a disc of a Tufnol like
material which was
relatively easy to shape yet is hard wearing, I have heard of someone
a bicycle drive cog to good effect.
The latch is just a piece of
metal hinged so that its own
weight causes it to engage and it is controlled with a simple
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"Only by going alone in silence, without baggage, can one
truly get into the heart of the wilderness.
All other travel is mere dust and hotels and baggage and chatter."
My greatest fear
about using the wind vane is if I should fall overboard and have to
boat merrily sailing away form me.
OK, that can happen without
self steering which is why I
always (well nearly always) clip
on when I'm sailing alone.
I have read suggestions about
trailing a long line with a
float on the end, umm, that’s ok if you are able to swim to it in time
catch it, I’ll stick to my harness and safety-line thanks.
And remember that while a wind
vane might do a great job
of helming your boat it won't keep a lookout, that’s still your
However, I have found that
being relieved of the need to
helm allows me more time to look around.
And on the subject of looking
around don’t forget
that extra bit of gear sticking out of the transom when docking mooring
Also remember that your vane
can only react after the
boat has moved off course, it isn’t able to anticipate the sea
or wind shifts.
If you do need to make an
emergency course change the
wind vane mechanism should be easy to disengage.
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