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Operation
 Operating
principle of the Servo-Pendulum Self-Steering
The turret is rotated until the apparent wind hits the windvane on its edge.
As long as the boat is on course, the wind pressure on both sides of the
vane is equal so that it stays vertical, and the steering oar stays vertical
in the water. If the direction of the boat changes in relation to the wind,
the vane is tilted by the wind hitting it on one side. This tilt of the vane
turns the stock of the steering oar. Because of the forward movement of the
boat through the water, this turn of the steering oar (also called
" Servo-pendulum ") causes it to be pushed with great force sideways,
turning the horizontal shaft that passes through the transom, rotating the
quadrant at its forward end and pulling on the control lines attached to the
tiller, to the wheel or to the boat’s steering quadrant.. As the yacht comes
back on course, the tilt of the vane decreases and the steering oar comes
back to vertical.
The steering oar (servo-pendulum) can also be controlled by a small electric
auto-pilot placed inside the lazarette. The power needed to steer the boat
is still provided by the servo-pendulum and the autopilot, providing only
the information, uses only a few mille-amperes from the batteries.
Connecting Procedure
1 : Set
the Course
The turret is rotated until the apparent wind hits the windvane on the edge.
(The higher side of the angled rod at the top of the turret points into
the wind and the hook is to leeward.)
2 :
Cleat the Control Lines
Cleat the control lines on their marks. If you can not cleat both of them at
the same time, first cleat the one that causes the boat to bear away (it is
doing most of the work) and take up the slack with the other one.
3 : a)
Fine Tune the Course Adjustment.
Fine tune the course adjustment, so that the boat maintains the precise
compass course (or point of sail) required.
b) Limit
Yaw
 When
we have learnt to sail, we were taught to steer with a minimum of rudder
angle, in order to maintain boat speed to a maximum. This is also true with
self-steering and you want your vane to give just enough rudder angle to
stay on course, but not more. The amplitude of the corrections is reduced by
limiting the tilt of the windvane. Adjust the tension of the short piece of
bungee-cord on the crescent by passing it through the nylon loop on top of
the course adjustment disk.
c) Trim
the control lines
If a boat is not perfectly balanced under sail and requires some weather or
lee helm in order to maintain a given point of sail, the length of the
control lines can be adjusted to induce a certain rudder angle so that when
the boat is on course, the steering oar is approximately vertical in the
water and the amplitude of the correction is roughly equal on both sides.
If the wind varies in strength. the co ntrol
lines may need to be re-adjusted.
IMPORTANT
: When tacking, be sure to invert the trim of the control
lines. Any lack of sail balance that the rudder angle was correcting on the
previous tack, is now increased by this rudder angle being inverted. Failure
to invert the trim on a new tack, makes the job much more difficult for any
self-steerer.
After the vane is connected, it is a good idea to have a look at the
windvane quadrant, to ensure the lines are working as they should, and that
nothing is fouling them.
Additional Information
Windvanes
Two windvanes are supplied : a smaller one, made of aluminum sheet, for
heavy weather, and a larger and lighter one, made of 1/8 in. dia. stainless
steel wire and nylon, for added sensitivity in light airs. It is recommended
to change over to the small vane
after the first or second reef.
The light air vane extends 24 in. (60 cm) above the top of the tower, and
the heavy weather vane, 17 in. (43 cm)
The windvane is inserted into a slot cut on the top part of a
crescent-shaped tube, and held in place with a thumbscrew.
Windvane
Supporting Crescent
 The
crescent-shaped piece sits on the angled rod, inserted in a hole on one
side, and into a slot on the other, with a concentric sliding collar held in
position with a split pin. This pin is also inserted into the hook at the
lower end of the angled rod, and transmits the tilting movement of the vane
to the rest of the mechanism.
The counterweights have been adjusted before delivery and normally, there
should not be any need to change this adjustment, unless some weight is
added to the light air vane. They are adjusted so that in calm air, the
light air vane just comes back to the vertical after it has been tilted. The
heavy weather vane does not need any special adjustment, as there is always
plenty of wind when it is in use.
You will notice that this crescent is offset to one side, and the
counterweights are sometimes bent to one side : it is because the weight of
the crescent is used to counter-balance the weight of the connecting rod
inside the windvane tower; the higher the tower, the more the counterweights
have to be offset to the side to balance the added weight.
When the gear is out of commission, or when the Cape Horn
is used in autopilot or remote steering mode, the crescent and vane are
removed and stowed.
Steering Oar
 The
steering oar is linked to its stock with three turns of shock (or bungee)
cord between the mounting plate of the oar and the hook on the stock,
maintaining the two notches on the plate in contact with the two transverse
pins on the stock. This allows the oar to break off if it hits an
obstruction, and prevents damage to the stock or to the oar itself.
Tension on the shock cord is adjusted to maintain the oar in place, except
when an effort beyond normal is imposed. If it breaks too often, without
apparent reason, increase the tension on the shock cord.
The only spare part you really need is a piece of ¼ in. (6 mm) shock cord.
Experience has shown that 21
in. for Jean-du-Sud and
28
for Spray was the correct length to allow 3 turns,
three twists
and the length needed for a fisherman’s bend and leave sufficient tension to
keep the steering oar in place.
The small nylon loop around the three turns of shock cord is a " handle " :
it makes it easier to grab the three turns together.
Safety
line
Should we mention it? It is essential to have a safety line on the steering
oar, to avoid seeing it disappear in the wake, the first time it breaks off.
Flipping
the steering oar up when underway
The easiest method of flipping the paddle up when under way is to tilt the
windvane crescent, which will cause the servo-pendulum to swing to one side,
then pull it up out of the water to " park " it along the tower. Do not pull
directly on the safety line, as this will turn the paddle in the wrong
direction and the water flow will cause it to move the other way. If you
want to use the line, pass it in front of the stock, and pull from that
side. This will cause the servo-pendulum to turn in the right direction and
the water flow will help it to come out of the water.
Ideal
size of the servo-pendulum
Power
generated by the servo-pendulum is proportional to its wetted area and to
the square of the speed of the boat. From this, we see that servo-pendulum
area is critical only at low speed. At higher speeds, the pendulum generates
considerably more power than needed to steer the boat.
Experience has shown that the wetted area of servo-pendulum needed to steer
at 2-3 kts to be somewhere between
8 and 12 % of the yacht’s rudder area. Closer to 8 for a high aspect-ratio,
partially balanced rudder steering a well balanced boat, and closer to 12
(or more) for a low a spect
ratio rudder, on a boat that is not so well balanced, or has a wheel
steering system with a lot of internal friction. We normally take into
account the yacht’s rudder dimensions and the height of the horizontal axis
above the waterline in determining the length of the servo-pendulum for a
given boat, but if you find that your pendulum does not generate adequate
power to steer your boat at slow speeds, please contact us and we will
provide you with a longer one.
A sailor concerned with reducing drag to a minimum could order two steering
oars : a longer one for light air or slow speed, and a shorter one for
higher speeds.
Balance under sail
With any kind of self-steerer or autopilot the secret to top performance is
sail balance.
Do not expect your gear to steer a straight course if the sails constantly
pull the boat to one side, and the self-steerer has to correct this tendency
before it can do its job of keeping the yacht on course.
The mast should be tuned to render the helm as neutral as possible in
medium air. When a boat is steered by hand, it is recommended, for safety
reasons, to tune the rig with some weather helm so that if the rudder is
left free, the boat heads up into the wind and stops. Now that the boat is
destined to make passages under self-steerer, this safety feature is no
longer desirable: if the helm is left free, the boat should keep sailing in
the same direction as much as possible.
When under way, watch the course for a while: if the gear always corrects on
the same side, it might be that the sails are not set properly. Trim the
sheets until the oscillations are about equal on each side.
Choose sail combinations to favor sail balance. If the wind is aft of the
beam, favor sail area forward. On a broad reach, pole out a jib or a genoa
as soon as possible (keeping a second jib to leeward if necessary). This
improves sail balance and the boat sails a much truer course.
Reef
when needed
On a relatively narrow boat, heel is the first sign that indicates that it
is over-canvassed. But more recent, beamier boats do not heel; as the
wind builds up, they acquire weather helm. Often, the wind freshens
gradually and as there is no one at the tiller or wheel, this added weather
helm goes unnoticed. Whether it is steered by hand or by a self-steerer, a
yacht sails better with a moderate heel and the right amount of sail. A
self-steering system does not alleviate the necessity of reefing when
necessary.
Connection to electric autopilot
It is possible to connect an electric autopilot to the servo-pendulum of the
Jean-du-Sud and Spray models. Thus, the energy to
turn the rudder comes from the water flowing along the hull, instead of
coming from the batteries, and the smallest autopilot can control a large
yacht. Placed just in front of the quadrant, inside the lazarette, the
autopilot will be protected from spray and since it has a very light duty to
perform, its life will be much longer.
At the end of the autopilot ram, there is a hole made for connecting a
vertical pin on the tiller. Turn the ram ¼ turn, drill this hole all the way
through with a ¼ in. drill, and insert the L-shaped rod through this hole.
Insert the dovetail-shaped plastic connector at the other end of this rod
into the corresponding piece, at the end of the horizontal control axle.
A tiller autopilot that is
designed to be mounted to port will also go to port if it is placed
below the control axle. It can also be placed above and be
mounted to starboard. However,
the autopilot can be connected with equal effectiveness above or below the
horizontal axle, placed to port or to starboard. If the correction of
the autopilot is on the wrong side, flip the changeover switch on the unit.
The 1/4" rod
is held by friction inside the dovetail-shaped plastic piece; it can be
pulled out and inserted from the other end. The amplitude of the
correction given by the autopilot can be increased by shortening the rod.
It is possible to mount the autopilot elsewhere and link it to the steering
mechanism with light control lines.
When the autopilot is used, the windvane and crescent on the top of the
turret are removed. Conversely, when the unit is controlled by the windvane,
the autopilot rod is disconnected, in order to reduce the inertia of the
mechanism.
Note: rigging steering lines to the control rod also renders remote power
steering possible.
Stowage
For short periods, the steering oar can be swung 180° to rest along the
windvane tower.
For longer periods, the steering oar and windvane (with crescent) are easily
removed and stowed below.
Maintenance
After the gear has steered half way around the world, or after two or three
seasons, it is prudent to make sure there is some waterproof grease left in
the slot in the pendulum stock, to prevent wear of the bent rod passing
through it. Remove the cap at top of the tube and insert grease through the
hollow top part of the stock, using a stick or a piece of wire.
Do not use grease or WD40 (or equivalent) to lubricate the plastic bushings.
The Teflon bushings need no lubrication, however, an occasional squirt of
silicone spray on the Teflon bushings of the windvane, connecting rod and
steering oar will contribute to maintain top performance in light air.
As with other stainless steel equipment, a regular polish will maintain its
bright finish.
Installation of Integrated Units
If installation of your Cape Horn is done according to the instructions
below, we guarantee that it will steer to your satisfaction. Most problems
with the Cape Horn are caused by an improper installation.
You will most probably gain time by reading the instructions below : they
may prevent many time-consuming mistakes.
.
Installation of Integrated Models
Installation of the models Jean-du-Sud and Spray is done in 5
steps :
1 : a) Position the Gear
b) Trace the center of the Mounting Tube hole
2 : Drill the hole and fasten the Mounting Tube
3 : Insert the Control Axle and fasten the quadrant to it
4 : Install the Windvane Tower
5 : a) Connect the control lines to Yacht’s Steering system
b) Rig Lines for Remote Course Setting
It
is possible (and even easier) to install afloat, provided the boat floats in
its lines, water is quiet and the stern can be brought to a dock. If
the boat is on the hard, ensuring that waterline is level allows the use of
a level on the horizontal axle and vertical windvane tower; otherwise, you
will have to rely on your eye.
1 : a) Position the Gear
It is the mounting tube that passes through the transom, and through which
pivots the horizontal axis between the servo-pendulum and the quadrant,
which determines the position of the gear. Hence, positioning the mounting
tube is positioning the entire gear.
The mounting tube should be in a line parallel to the fore-and-aft centerline
of the boat (the keel)
 However, it can be mounted off-center, in order to avoid cutting or
moving the backstay chainplate gusset. Performance of the gear will not be
affected if it
is offset to one side (provided it is kept parallel to the keel).
It can even be offset enough to allow a transom-mounted rudder to pivot.
Height
Above Water
Drag of the servo-pendulum is kept to a minimum when the metal plate that
links the servo-pendulum to its stock is out of the water. Therefore, the
height of the mounting tube above the waterline (HWL) should be at least
13.5 in. (34 cm) for the Jean-du-Sud
21.5 in. (55 cm) for the Spray.
If the horizontal axle must be lower, it is
possible to shorten the stock of the servo-pendulum. Conversely, if it must
be much higher, it is possible to provide either a longer paddle or a longer
stock.
Positioning the
tube
fore and aft
Aft
: The aft end of the tube must clear the aftermost part of the transom or
stern. It must also clear the trailing edge of the rudder by at least one
inch (25 mm) if it extends past the hull.
Forward
: A reasonable distance between the transom and the struts supporting the
forward end ensures a strong installation. This distance (D) should not be
much shorter than the overhang (O) between the transom and the outboard end
of the mounting tube
Provision for 360° Quadrant Movement
The radius
of the quadrant is
- 8.25" (210 mm) for
Jean-du-Sud
- 11"
(280 mm) for
Spray
 Consequently, at
the forward end of the tube, a circular space (CS) of a diameter
-
16.5"
(420mm) for Jean-du-Sud
- 22" (560
mm) for Spray.
Quadrant thickness is
-
1" (25 mm) for Jean-du-Sud
-
1 1/4" (32 mm) for Spray.
If space is restricted, it is possible to
provide a quadrant with a shorter radius.
Provision for connecting an autopilot to the steering oar
The co-axial control rod that steers the servo-pendulum extends in front of
the horizontal axis, in front of the quadrant.
In front of the quadrant, there should also be enough
space for the autopilot itself,
unless it is located elsewhere and connected through light control lines.
1 : b) Trace the Center of the Mounting Tube Hole
Transferring various measures to points on the transom, inside or out, is
much easier when the boat
is floating in its lines; if the boat is on the hard, ensure the
waterline is level, both fore-and-aft and athwartships. In this case, a line can be strung above the rail, made
perfectly level and parallel to the keel, and used as a baseline. In most
cases, From it, you can drop a plumbline through an opening in the lazarette
to transfer measures inside.
Make good use of the level and the square. If the yacht is stable, also use
the plumbline (it is easy to improvise one); use it in particular to
materialize both ends of the mounting tube and to determine the position of
the quadrant..
Carefully mark the center of the hole on the transom or hull, both inside
and out.
When this is done, do not grab the drill yet. Repeat each step of the whole
measuring operation, to double-check. Remember this is the most
critical part of the installation process and has to be done with greatest
care.
If you arrive at the same results twice, you can go ahead with a clear
conscience and drill the center guiding hole.
2
: Drill the Hole and Fasten the Mounting Tube
2 : a)
Drill the Hole
Drill a hole 1/8 in. (3 mm) or smaller first. If you are satisfied with its
position, drill 1/4 in. If not. Drill an other smaller hole in the right
position. Drilling a small hole first makes changing its position easier. Do
not worry about drilling more than one hole, as this section of the transom
will be removed when you drill the large hole.
Cutting the Mounting Tube hole through the transom is easier than it
appears, with a good quality hole saw :
-
2 1/2 in. (63 mm) for Jean-du-Sud
-
3 1/2
in. (89
mm) Spray
 The secret is to maintain the tool very steady,
level and parallel to the centerline. This way, you will eaily cut
through the transom, even if it is at an angle, or if it is a canoe
stern. If the drill is held very steady, the hole-saw will not bind.
 To make it easier to drill perfectly level
and parallel with the keel, you can replace the
center 1/4 in. drill bit of the hole-saw
holder by one that is 18 inches long (easily found in most hardware stores).
It then becomes possible to place a small level on the drill. It also
allows placing a straight batten on deck, extending past the transom,
parallel to the keel and having an assistant looking above, guiding your
hand left or right.
2 : b)
Fasten the Mounting Tube
The Mounting Tube must be very strongly attached to the transom and hull.
Aft, it must absorb the drag of the servo-pendulum through the water, and
forward, the torque of the quadrant and pull of the control lines.
Notice that the Mounting Tube is marked fore and aft : the two bushings at
each end are slightly different (the aft one is larger,
due to the fact that at welding, the horizontal axle may have become
slightly oval, and the chamfer is a bit deeper, due also to the weld);
Hence, the tube must be inserted accordingly.
 Fasten
the Forward End
The forward end of the mounting tube is held in place with two struts
bolted on the tube at angle between 90° and 120° and cut to reach
either the underside of the deck above, or pads fiberglassed to the hull
below.
 The struts are
cut to the appropriate length, (the tube has one turnbuckle-type end, which
allows a 2 inch adjustment of its length) and a ¼ in. hole is drilled
through it, ½ in. from the end (make sure this hole is drilled at 90°) for
bolting to the flat U-shaped bracket.
Two holes are drilled, dia 5/16 in. (8
mm), 1 ¾ in.
(44.5 mm)
apart (center-to-center) through the Mounting Tube; the curved back-up plates are placed inside it and
the curved U-shaped brackets are bolted on the tube.
The
bushing extends 1" inside the tube; consequently, the center of the struts
should not be closer than 2" (50 mm) from the end
The inside curved back-up plate is covered with a double-sided adhesive
tape, that will keep it in place until it is bolted. Peel away the
protecting paper before inserting.
The length of the struts is fine-tuned, using the turnbuckle end, to ensure
the tube is level and parallel to the keel.
Bolting
Struts to pads
If the struts can not be
bolted to the underside of the deck, they can be led to pads which are
bonded to the hull with epoxy.
Those pads, measuring 4" x 4" (or 4"x 6" if they are used for both the
struts and blocks), min. 3/4" thick are made with either hard wood or
plywood. Cutting the edges to a
45° bevel makes it easier to
bond with fiberglass tape. U-shaped fittings and straps for blocks are through-bolted from
the underside, using countersunk bolts, with the nut on top.
The surface of the hull is ground to expose bare fiberglass; all
surfaces are coated with epoxy, then bedded in thickened epoxy making
sure there is no void between hull and pad West
system 404 filler provides the best bond). The bevelled edges of
the pad are covered with fiberglass tape or mat. |
Fastening the Aft End
Glassfiber or wood hulls
Once the fore-and-aft position of the tube has been determined, the
struts cut and positioned, the tube can be bonded to the transom.
Mark
the contour of the transom on the tube with a grease pencil or a marker,
both inside and outside. Then grind with a power grinder or a file, stopping
1/4" short of its outside end, and about one inch past the inside mark.
On the inside of the hull, grind also about one inch around the hole, to
remove existing paint and expose bare fiberglass.
Apply a coat of epoxy (with hardener) to the ground portion
of the tube, and
also to the inside and sides of th e
hole in
the hull.
Thicken the epoxy with filler until it does not sag when you take a gob at
the end of a stick and hold it for about 10 seconds. Fill the gap between
the tube and hull and make a fillet inside. For an even better joint, you
may add one or two layers of 2 inch wide glass tape.
 A light bead of sealant makes a nice finish outside.
Metal
Hulls
The Mounting Tube can be welded to a steel hull, provided welding is done
carefully
to minimize tube deformation.
An aluminum Mounting Tube can be supplied for welding to an aluminum hull.
 If welding is not practical, an optional Delrin Collar adapter can be
used to bond the tube to the hull.
 The
Collar is cut to the angle of the transom, and the two halves are inserted
over the mounting tube, one from the inside, the other from the outside,
taking the transom in sandwich, and the two halves are bolted together,
using a liberal amount of sealant to fill all voids.
If we are given the angle the transom makes with the horizontal, this collar
can be provided precut.
3 : Insert the Control Axle and Fasten the Quadrant
3 : a)
Insert the Control Axle
The Control Axle is now inserted into the Mounting Tube. It should turn
reasonably freely. If it does not, it may be either because the tube has
been inserted back to front, or because welding has pulled the tube out
of shape. In the first instance, if the tube has already been bonded to the
hull, all is not lost : just switch the two plastic bushings.
In the first instance, or if switching the two bushings has not solved the
problem satisfactorily, smear both ends of the control axle with a felt
marker and rotate it inside the mounting tube : the ink will be transferred
to the tighter points on the bushings which can then be scraped or sanded
away.
3 : b)
Bolt Quadrant
Quadrant
above of below the axle ?
The quadrant can be placed either with the groove above the axis
or with the groove below. Whether it is mounted one way or the
other is determined by the most convenient placing of the first pair of
turning blocks and the most direct routing of the control lines to the
rudder quadrant, wheel or tiller.
All the power transmitted to the yacht’s rudder is concentrated
on the link between the quadrant and the horizontal shaft; this is why
the quadrant must be bolted very tightly on the axle.
Tighten first the two bolts on the center of the shaft itself, then the two
bolts and nuts on either side of the collar. After the first few hundred
miles of self-steering (or first bout of heavy weather), re-tighten if
needed.
4 :
Install the Windvane Tower
Braces
The windvane tower is kept vertical by two diagonal braces made of SS tube
7/8 in. OD supplied with their appropriate fittings for fastening to the
tube at one end and to the deck at the other. These braces can be placed
wherever convenient to provide adequate support. On the tower, they
are connected with 2 U-shaped curved plates that are bolted to an inside
back-up plate. They should not be higher than 2 ½ in. below the
course-adjusting disk, to allow space for the back-up plate inside the tube.
 On
the tower, drill two holes dia. 5/16 in. (7 mm), on 1 ¾ in. (44 mm) centers
at the correct height.
In marking these holes, make sure the short horizontal tube at the
base of the tower lines up perfectly fore-and-aft, in the same plane
as the mounting tube, otherwise the ring into which the base of the tower is
screwed may bind and keep the axis from turning freely. If in spite of your
precaution, the ring binds after it has been connected to the base of the
tower, it can be brought back in line by enlarging the four holes that have
been drilled into the tower on one side, to allow the tower to pivot until
it is brought back in line. Since the U-shaped bracket covers the holes,
nothing will show.
Bringing the threaded back-up plate in
position inside the tube requires a little ingenuity :
Tie a small nail around its center at the
end of a piece of light line long enough to reach the bottom of the tower,
then feed it through the top hole until it drops to the bottom of the tube.
Pass the nail through the top hole of the backing plate and pull it up with
the string. When it comes in position, insert the bottom screw, then
remove nail and string, and insert the top screw. The back-up plates
are fitted sith double-sided adhesive tape to keep them in position; peel
off the protecting paper before insertion.
Provided some angulation between them is kept, the braces do not need to
be placed symmetrically. One of them can be placed almost fore-and-aft,
and the other to one side, to allow passage through the stern on one
side.
Connecting the windvane tower to the horizontal axle
The short tube welded horizontally at the base of the windvane tower is
fastened to the control axle with four screws through its edge, into a ring
revolving freely at the end of the horizontal axle. Two punch marks identify the top of the ring and makes alignment of holes easier.
Connecting the Control Mechanism
The
handle that controls the steering oar should be to the left
(to port) of the small vertical rod that bisects the short tube at the base
of the tower. The function of this vertical rod is precisely to keep the
handle from rotating more than half a circle and maintain the connecting rod
to the left.
At the bottom of the pushrod that moves up and down inside the tower (and
transmits the tilt of the vane to the steering oar), is screwed a connecting
rod made with a piece of threaded rod welded to a short piece of tube with
Teflon lining inside. Notice that the threaded rod if offset to one side.
Connect it to the handle so that the short tube is offset to port
(left, looking forward); this keeps the pushrod away from the wall of
the tube.
5 : Rig Control Lines
Type and
Size of Lines
We recommend rigging rather light control lines, in order to use them
as a fuse. A control line is easily replaced and in the case of a
sudden overload, it is better to break a control line than some other
component of the system.
We recommend control lines made of polyester if they are relatively short,
or Spectra if they are rather long, as this material stretches less, of a
dia. ¼ in. (6 - 7 mm) for Jean-du-Sud , or 5/16 in. (8 mm) for
Spray. Alternately, in order to reduce stretch, a larger
diameter line can be used, but in this case, it is prudent to provide a
" weak link " somewhere in the system, for example by fastening a block with
a lashing that will break before something else gives way.
First
Pair of Blocks for Control Lines
The control lines are fed through a hole at either end of the groove on the
edge of the quadrant and prevented from pulling through with a figure-eight
knot.
A
loop made of bungee cord
crossed over
the top helps keeping the lines inside the groove
They are led through turning blocks on either side. The turning blocks
must be solidly secured, to very strong points, as they
absorb the total steering effort and more. The blocks must be positioned
so that each line works precisely in the axis of the quadrant groove.
They can be placed higher or lower, as long as they allow the line to line
up with the plane of the groove.
The distance between the quadrant and the turning blocks is immaterial so
the blocks can be placed close to the quadran
t or away to the sides. The sheaves of all the blocks must be allowed to
line up freely with the lines (if not, the lines would chafe through very
rapidly).
Direct Connection to Yacht's Steering
System
 The
control lines can be
connected directly to the
yacht’s steering system.
They are led through turning blocks fastened to the quadrant (or to a short
auxiliary tiller such as the tiller of a hydraulic system), pulling from
a direction 90° from the attachment point of the blocks on the quadrant
(or tiller) and the rudder axis.
 After passing through the blocks on the
quadrant (or tiller), the control lines are led back to a fairlead placed
close to the last turning block. From there, they are led to jamming cleats
placed within reach of the wheel.
If
the blocks are fastened to the rudder quadrant, it is better to fasten them
to its underside, to prevent fouling the steering cables with the control
lines when they are loose.
The vane is connected by putting the lines in tension and cleating them; it
is adjusted for weather or lee helm (if any is needed to maintain a given
point of sail) by varying the length of the lines. Releasing the lines from
the jamming cleats instantly disconnects the vane and allows to take over
manually.
Note
: when the vane is in operation, only the segment of control lines between
the two quadrants (or vane quadrant and aux. tiller) moves and therefore,
needs to be led through blocks. The segment between the rudder quadrant (or
tiller) and the jamming cleats does not move, it is only kept in tension and
can be led through fairleads instead of blocks.
Position
of the Turning Blocks
on steering quadrant
The ideal ratio between the tilt angle of the pendulum + quadrant, and the
rudder angle is 2 : 1.(for 10° of pendulum + quadrant tilt, 5 ° rudder
angle). Since the turning blocks on the rudder quadrant (or tiller) divides
the travel by half (and doubles the force), the distance between
these blocks and the rudder axis should be equal to the
windvane quadrant radius : 8 in. (20 cm) for Jean-du-Sud
and 10.1/2 in (27 mm) for Spray.
Leading the Control
Lines to the steering quadrant
The
horizontal axle and the rudder stock should move in opposite
directions : when the pendulum and quadrant pivot clockwise, the rudder
stock should turn anti-clockwise. When
the CH quadrant is above the axle and the blocks on the vessel’s quadrant,
disk or tiller are forward of the rudder stock,
the lines are connected directly. When the CH quadrant is below the axle
and the blocks on vessel’s quadrant are behind the stock, the lines are also
connected directly. If the CH quadrant is below and the blocks are forward,
then the lines need to be crossed. If the CH quadrant is above and the
blocks are aft, the lines also need to be crossed (refer to examples
below).
A few examples of direct connection
(Click for more details)
Jamming Cleats
The
jamming cleats should be located within easy reach of the wheel. Whenever
possible, they should, placed side by side, which allows tying the two lines
in a knot when the rudder is amidships and quadrant and pendulum are
vertical, and to find this position automatically by pulling the two lines
together. (If the cleats can not be located together, the lines should be
marked to locate the position rudder amidships and pendulum-quadrant
vertical.)
If
the jamming cleats are located above the holes (instead of below), the lines
can be pulled and cleated in one single movement.
Connection to Wheel or Tiller
The control lines are led out through holes drilled in the sides or back of
the cockpit bulkhead, then (trough other blocks if needed), to the wheel or
tiller..
The turning blocks must be placed in such a manner that the control line is
guided exactly in the center of the hole, and that it does not touch its
side; otherwise, it will chafe through very rapidly. In the case of a line
chafing on one side, enlarge the hole with a round file or a Dremel tool.
Connection
to Wheel
 The control lines turn the steering wheel by going around grooved Delrin
cylinders placed on the wheel spokes, then to a cleat. These cylinders
can be placed closer of farther from the hub, so the ideal ratio of rudder
angle for a given quadrant tilt can be arrived at. This ideal ratio is 2 to
one: for 10° of pendulum-quadrant tilt, 5° of rudder angle.
An autopilot drum already fitted to the wheel poses no problem : the
cylinders are placed inside this drum and when it is to one side of the
wheel, they can be place on the other side.
Connection
to Tiller
  The
control lines are led through fairleads placed on either side of the tiller,
and then forward to a pair of jamming cleats. These fairleads should be
placed at a distance from the rudder axis, close to twice the quadrant
radius :
16 in. (40 cm) for Jean-du-Sud, and 21 in. (24 cm) for
Spray.
If connection is done on an auxiliary or emergency tiller, it can be kept
shorter by connecting in the manner described under "Direct
Connection to Yacht’s Steering System ".
Rig Lines for Remote Course Setting
 The
friction of a 5/32 or 3/16 in. (4 - 5 mm) endless line inside a groove at
the base of the control disk rotates the revolving turret at the top of the
windvane tower and allows to set a precise course from a remote position.
Two rollers guide this line down to blocks at deck level. Leading this
endless line through blocks around the cockpit (along the coaming)
allows to set the course from any position in the
cockpit, even from below by reaching through the companionway.
Important : The turret is built to
revolve freely; consequently, if this endless line is not used, rig at
least a line down to the struts to create additional friction and
maintain set course. Otherwise, the wind will cause turret to revolve by
itself and course will vary.
If the turret becomes stiff and the line slips in the groove, put a
rubber band in the bottom of the groove to increase friction.
Installation
of Outboard Models
 Assembling the Varuna or Joshua
In order to reduce the volume of the parcel for shipping, the mounting arms,
the horizontal axis and the tower are shipped unassembled. The assembling
procedure is as follows :
1 : Insert the horizontal axle (the T-shaped piece) through the horizontal
tube at the base of the tower. As you push the piece through the tube (and
before putting the bolts through the bronze collar), connect the crank at
the forward end of the tower in the manner described and illustrated in "Connecting
the Control Mechanism".
When this is done, insert the bottom bolt through the bronze collar (the
other three will be inserted after the arms are assembled). Note that this
bottom bolt is shorter than the other three.
2 : Assemble the vertical tower to the mounting arms. The base of the tower
goes inside the curved plate on which the two arms meet. Insert the two
bolts through the small curved plate welded to the horizontal tube linking
the two arms. Insert the three through the curved plate where the two arms
meet, into the bronze collar. Tighten moderately.
Installation
to the transom
If the freeboard is less than about 28 in., the mounting arms can be bolted
to the deck or taffrail. If it is greater, they are bolted to the transom.
Cut the mounting arms to the appropriate length, so that the body of the
unit or the steering oar clears the rudder by at least an inch.
 The arms should be fastened to the transom at a height
that keeps
most of the wood part of the servo-pendulum below the (dynamic) waterline,
while keeping the metal plate at the top of the steering oar out of the
water in normal sailing conditions.
Control
Lines
The control lines are connected to the vertical control arm in this manner :
in the middle of a continuous line, tie a clove hitch around the short piece
of tube. Insert the tube inside the control arm and insert the bolt through
the arm and tube. Pass the two segments of the control lines through the two
holes in the cap and put the cap in place at the end of the control arm.
Shackle a turning block on the half-ring on each side of the mounting arms
and pass the control lines through. From there, the control lines are led to
the tiller or wheel in the manner described in "Connection
to Wheel or Tiller".
Installation
of the Toucana
 Installation of the Toucana is only a matter of cutting the mounting arms to
a length that keeps most of the wood part of the servo-pendulum below the
(dynamic) waterline, while keeping the metal above it most of the time, and
fastening them to the underside of the boomkin. Fasten also the diagonal
struts to either the boomkin or the hull.
 An Omega-shaped strap can be used to fasten the tower to the boomkin.
Additional diagonal struts can be added to the boomkin for more support.
Guarantee
We build the Cape Horn with the greatest of care, and when we ship a
unit, we have the assurance that it could steer us around the world.
We naturally expect that comparable care will be given to installation.
We guarantee its performance for one circumnavigation, 28 000 miles or three
years against any damage caused by the wind or the sea.
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