A Vane to Steer Her By - Boating Writers International

Transcription

A Vane to Steer Her By - Boating Writers International
Hands-on sailor
Practical solutions + techniques
Thanks to its light weight and
corrosion resistance, the stainless-steel Monitor windvane,
from Scanmar International, is a
popular accessory on long-range
cruising boats (above).
The Hydrovane windvane is an
example of an auxiliary rudder
system (ARS). One of the great
advantages of this model, as
shown on a Wauquiez 43 (left),
is the ability to offset the vane
when mounting to accommodate
a transom boarding gate.
A Vane to Steer Her By
Once found only in
the ascetic realm of singlehanded sailing, self-steering
gear has become ubiquitous
on cruising boats, even
fully crewed ones. That’s
because a self-steering unit
serves as an additional hand
that possesses relentless
concentration at the helm;
subsists on only amps or
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lubricants; and, if properly
trained, does what’s asked
of it without question or
complaint.
Reliable remote control of
the helm relieves the fatigue
and monotony of following
a compass course at night. It
allows time for sail changes
and adjustments; horizon
sweeps for ships; attentive
navigation; and that quick
dip below to check the
bilges and grab a hot drink.
Without question, selfsteering makes for a more
relaxed, enjoyable and safe
voyage.
But the debate over
which kind of self-steering
is best — electric or
windvane — rages on. I
may be an old-fashioned
belt-and-suspenders kind
of sailor, but I believe both
systems have their different
strengths and weaknesses,
and therefore complement
each other. In other
words, any vessel that is
configured in a way that can
accommodate both methods
should do so.
courtesy of the manufacturers
Voyaging: When it comes to simple, robust, reliable self-steering — especially in snarly weather — a
mechanical windvane is hard to beat. By
Hands - On Sailor
The bulletpro
vane
on my cutter,
has
served me faithfully for over
three decades and two circumnavigations, and shows every
indication that it will ultimately
outlast me ( far left).
(above); courtesy of the manufacturers
Manufactured in Sweden since
1976, Sailomat windvanes
employ the servo-pendulum system (SPS) and are available in
models to fit yachts from 26-55
feet LOA (top left).
In this scenario, the more
robust mechanical windvane
would be employed in
heavier weather, while the
electric autopilot would be
used in light airs and under
power, where directional
corrections are provided not
by the wind, but by a fluxgate
compass. It is important to
understand that while the
electric autopilot maintains
a steady compass course, a
windvane is set to maintain
a desired angle off the
apparent wind, and therefore
will follow any wind shifts
or changes in wind velocity.
While this does keep the
sails perpetually in trim, the
course must be monitored
closely when in confined
waterways.
That said, if forced to
choose, I would go with
the mechanical windvane,
hands down. Vanes don’t
rely on the ship’s electrical
The simple yet elegant Cape
Horn windvane can be customfitted to just about any transom,
including this canoe stern (top
right). The company guarantees
their vanes for 28,000 nautical
miles or a complete round-theworld voyage.
Voyager windvanes are now
constructed of aluminum with
no stainless-steel parts with the
exception of carefully isolated
fittings and the pushrod inside
the air vane’s mast (left).
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Hands - On Sailor
power supply, which serves
as the last link in a long
chain of delicate electrical
components and breakable
mechanical parts. Across the
range of types and brands,
mechanical windvanes
generate amazing power
in rough conditions (when
needed most), coupled with
notable durability. Almost
30 years ago I purchased
an already well-used Aries
windvane. It has faithfully
followed me from boat to
boat, and around the world,
with clear indications
that it will outlast me. On
the other hand, I have an
overflowing box of spare
parts cannibalized from the
many electric tiller-pilots I
have chewed through in that
same period.
Types of Vanes
Introduced by the
indomitable Blondie Hasler,
founder of the OSTAR solo
transatlantic race in 1960,
the original windvane
consisted of a direct coupling
of a horizontally rotating
(vertical axis) vane to a
trim tab on the aft edge of
a transom-hung rudder.
Once the vane was fixed to
the desired angle off the
wind (using a round base
plate with notches spaced
at 5-degree intervals), any
course change rotated
the large vane like a
weathercock. This in turn
twisted the tab to one side
of the main rudder, driving
the rudder in the opposite
direction, thus bringing the
vessel back on course. The
advantage to this system
was its ease of construction
and low cost, but it was
best adapted to the waning
style of transom-hung
rudders. Also, a large vane
was required to harness
sufficient wind to power
the trim tab. Therefore,
especially in light airs,
the tall, heavy vanes often
reacted more to the yaw and
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roll of the vessel than to the
wind, resulting in erratic
meandering.
However, from this
early and rudimentary
concept, two sophisticated
yet distinct types of
vanes evolved: the servopendulum system (SPS)
and the auxiliary rudder
system (ARS). Both SPS
and ARS systems employ a
counterweighted horizontalor vertical-axis wind vane to
activate an appendage in the
water, but the similarities
end there. (To confuse the
issue, there is now a hybrid
system called the servodriven auxiliary rudder, or
SAR. But by first addressing
the two basic concepts, a
clearer understanding of
this marriage of ideas will
emerge.)
The SPS system — best
represented by brands
such as Aries, Cape Horn,
Fleming, Monitor and
Sailomat — uses the
movement of the windvane
to horizontally turn an
independent servo-rudder
(essentially a separate oar
or paddle) that is deployed
into the water. As the boat
moves, the laminar flow of
water presses against the
positive lead on the servorudder, generating sufficient
power to aggressively swing
the servo-pendulum, or
windvane, in one direction or
the other.
While it is the power of the
wind that directs the angle
the servo-rudder presents to
the passing water, it is boat
speed through that water
that exerts the considerable
pounds of pull on the lines
that run from the servorudder and through a series
of turning blocks, ultimately
connecting to the tiller (or,
in the case of wheel steering,
a drum in the center of the
wheel). More simply, the
servo-rudder does not turn
the boat; it pulls on the tiller
or rotates the wheel, which
One of the niftier features on most SPS set-ups, like the Monitor
windvane on this Valiant, is the ability to flip the servo-rudder out
of the water when it’s not in use (top).
On my 36-foot steel cutter, we use both an Autohelm ST400 tiller
pilot for light-air sailing and the Aries vane for more boisterous
conditions (above). In this installation, the electronic steering
arm should be optimally placed to best balance power vs. distance
of throw. Also note the double jam cleat on the tiller. By running
control lines through an eye bolt and back to the cleat, I can adjust
the tension of the lines to offset any weather or lee helm.
in turn moves the main
rudder.
Perhaps the main
drawback to this concept
is the limited throw of the
lines, as the distance of arc
through which the pendulum
swings is limited to the width
of its supporting frame, an
average of approximately
10 inches. This is no issue
when connected to a tiller
because one can fix the lines
at the optimum point on the
helm: high for more power,
lower for a greater turning
angle. But depending on the
stop-to-stop ratio of a wheel
steering system, the length
of pull may not be sufficient
to effectively control the
vessel. This problem can
be exacerbated by centercockpit designs, as longer
line lengths may stretch
more, further limiting the
effective length of pull.
The ARS system, best
represented in the market
by Hydrovane, employs
an altogether separate
appendage to steer the
Hands - On Sailor
A Hybrid Self-Steering
Solution
1
2
3
4
Unique transoms demand clever or even custom installation designs, such as the one found on this long, flat, “sugar-scoop” boarding platform (above). However, the ability to kick up the windvane’s
servo-rudder ensures optimum sailing performance when the vane
isn’t required, and trouble-free maneuvering in close quarters under
power.
(top),
(right)
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vessel. The boat’s main
rudder is usually fixed
amidship (or angled slightly
to offset a lee or weather
helm) and a second,
auxiliary rudder, directed
by a windvane, takes control
of the steering. Thus, it
is not only a self-steering
device, but can also serve
as an emergency rudder.
Considering that all four of
the Mayday calls I monitored
on one of my Pacific
crossings related to steering
failure, this redundancy has
considerable value. Because
of the forces placed on this
rudder it must be robust in
construction, well fixed to
the vessel, and of sufficient
design and size to handily
maneuver substantial
tonnage.
Pros and Cons
There is a heated online
debate among some of
the manufacturers and
distributors of the respective
systems, each dismissing
the supposed advantages of
the other’s design concept
while touting their own. I
have sailed with both servopendulum designs and
auxiliary rudders and found
both to be practical and
reliable; the final decision,
to me, comes down to the
type of vessel to which
they will be attached, the
steering system onboard, the
conditions of sailing most
likely to be experienced and
the budget.
In my opinion, the
auxiliary rudder is more
sensitive in light air, which
is the average condition
found in many recreational
sailing areas. I’ve found the
servo-pendulum model to
be rock steady in conditions
so rough that the average
helmsperson would be
exhausted within an hour.
But there are advantages
and disadvantages to each
approach. For example,
the auxiliary rudder has
no provisions for being
lifted out of the water to
clear flotsam and seaweed;
it can affect the backing
characteristics of a vessel;
1. This “custom adaptor,” made from G10, replaces the air
vane in certain conditions though the vane can be quickly
installed for upwind or heavy-air sailing. 2. A panhead screw
serves as a hinge and connects the tiller-pilot extension to the
adaptor. 3. The tiller-pilot extension is made from durable
PVC. 4. A quick-release pin allows for instant removal in an
emergency. 5. With Lyra balanced on a 6.5-knot beam reach,
the vane is properly tuned with the tiller pilot. The servo
rudder, blade and tiller pilot are in the approximate middle of
their throws, allowing for maximum course corrections.
Meet Hermione, our Aries Lift-Up windvane, and Wanderer,
our Raymarine Autohelm 2000 Plus. (As
notes, selfsteering kit tends to be named, and ours is no exception.)
Over the winter we took our Reliance 44,
on a 3,600
nautical-mile winter escape. We estimate that 2,800
of these miles were steered by this duo, affectionately
nicknamed “the autovane.” While this setup does not
steer as straight a course as a properly sized electric
quadrant-mounted autopilot, it was good enough to stay
in the channel on the Intracoastal Waterway and capable
in up to 5-foot seas offshore. Power draw averaged less
than 3 amps, 12 volts offshore and made it an inexpensive
alternative to a proper electric autopilot. With the remote,
we can steer a compass course, keep on course in light air
or go directly to a waypoint, all from under our dodger or the
companionway steps.
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Hands - On Sailor
Windvane Manufacturers
Aries Vane Gear (www.ariesvane.com for parts; www.selfsteer.dk
for new products); Cape Horn Marine Products (www.capehorn.
com); Fleming Marine (www.flemingselfsteer.com); Hydrovane
International (www.hydrovane.com); Sailomat USA (www.sailomat.
com); Scanmar International (www.selfsteer.com); Voyager Self
Steering Inc. (www.voyagerwindvanes.com); Windpilot (www.
windpilot.com).
and there’s no dedicated,
engineered, breakaway
“weak spot” when colliding
with something like a
submerged log. (In such
instances, most servopendulum rudders simply
flip up out of the way, and
are popped back in place
with the pull of a line.) On
the other hand, auxiliary
rudders don’t require lines
that obstruct the decks
and cockpit, a significant
advantage depending on the
1 PM
placement of the helm.
To the latter point, perhaps
too much is made of the
difficulty in fixing, releasing
and adjusting the tension
of the lines on an SPS vane.
I corrected this problem
with a $5 double jam cleat.
Instead of using the typical
link in a chain to connect
to the tiller, I run my lines
through an eye bolt on the
tiller and back to the jam
cleat. I can ease or tighten
the lines balancing friction
with precision; introduce
infinite increments of bias
to help balance the boat;
and even when under
tremendous pressure,
immediately release the
lines in an emergency
situation.
A subtle but potentially
important advantage of the
SPS is its natural aversion to
broaching. As a steep wave
slams into the quarter, the
vessel can violently swing
sideways. However, this
same sudden sideways force
BC_02
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pushes the servo-rudder in a
direction that immediately
tries to turn the boat back
down the face of the wave.
But even that point could
be countered with the claim
that by fixing the large main
rudder in place, as in an ARS,
substantial lateral stability
is added to the vessel, thus
minimizing any penchant to
broach.
When mounting either
system, the latest design
trends – open, aft-entry
cockpits and drop-down
transoms – present new
challenges. Hydrovane
makes the unequivocal claim
that its ARS can be mounted
off-center without affecting
performance. Offsetting
the vane opens access to
the sugar scoop and/or the
boarding and swim ladders.
But as drop-down transoms,
in particular, become ever
beamier, there is less flat
and fixed space available for
robust mounting. Depending
on the stiffness of the vessel,
one would not want to push
the vane too far outboard for
fear of lifting the auxiliary
rudder clear out of the water
on a heavy heel.
All SPS manufacturers
stress the importance of
meticulous centering during
initial installation. Adapting
to these new transoms,
Monitor has introduced
the SwingGate system to its
vanes. This is essentially a
pivoting pushpit, much like
a garden gate, with the vane
Hands - On Sailor
attached. When the gate is
open the boarding platform
or swim ladder can be
accessed, and when the gate
is closed the vane sits firmly
fixed amidship.
While completely
appropriate for trimarans,
windvane steering is not
well suited for catamaran
designs due to the dual
rudders and high bridgedeck clearance.
As to pricing, there is
no denying that the basic
ARS units cost from 25 to
40 percent more than SPS
models. Acting as the boat’s
main rudder demands that
the auxiliary rudder and
mechanisms be constructed
from heavy, high-quality
materials. But if one chooses
the swing-gate option, the
additional cost of the gate
structure must also be
factored in.
Summing Up
When choosing a selfsteering system, closely
assess the design features
of your boat and the
conditions you will most
often encounter. If you
intend to make any kind of
extended passages, consider
a high-quality mechanical
self-steering unit, possibly
coupled with a lighter
electrical system. Often,
the two can be combined,
offering the precision of
fluxgate steering with the
power and toughness of
mechanical systems (see
“A Hybrid Self-Steering
Solution,” page 57).
After the initial expense of
purchase and installation,
there will be no piece of
equipment on your vessel
more prized than your
mechanical self-steering.
I don’t know of a single
long-distance sailor who
has given a name to the
roller-furling system, nor
of one who has not named
the windvane. Be it SPS or
ARS, called Esther or Otto,
trust me, out there on the
Big Blue you will have
many long and meaningful
conversations with it.
But like all relationships,
this one requires practice
and patience. First and
foremost, do not ask the
windvane to make up for
sloppy sailing. Balance
your boat, starting with
waterline trim. Keep the
weight out of the ends
and ensure that the sails
are appropriately sized,
set and trimmed to the
conditions. Excessive
heel is not only slow, but
places the boat on lines
that the designer never
intended, resulting in poor
tracking. Ensure that the
windvane is not blanketed
by superstructure or
fed turbulent air via
barbecues, solar panels or
davits. Experiment with
different settings, such
as blade angle and line
tension, to understand
and optimize performance
in various conditions.
Models that employ a
mix of metals should be
disassembled, cleaned
and lubricated regularly
to minimize electrolysis.
When reassembling, use a
high-grade barrier cream
on all fasteners.
All models benefit from
an occasional bath of
scalding-hot fresh water
to dissolve any buildup
of salt, minerals and
solidified grease.
And finally, for those
concerned that these
protruding, industriallooking structures may
ruin the lines of an
otherwise lovely vessel,
remember: “The rougher
it gets, the better they
look.”
Coast guard.
Our new Coast Range combines all the
essentials for coastal waters – protection,
practicality and comfort. Featuring a highcut thermal collar, adjustable watertight
cuffs, soft comfortable fabric, and large
cargo pockets, there are several available
options to make sure all bases are covered
for excellent weather protection.
gillna.com
July 2014 | cruisingworld.com 59