Steering by the Wind

Seasoned offshore sailors who have experienced freak waves, knockdowns and serious equipment failures generally agree there is one piece of equipment without which they could not imagine leaving port: a wind vane self-steering system.

A scenario to consider: A retired couple with little or no offshore sailing experience sets off on an ocean crossing, and 800 miles offshore they are hit by a freak wave that swamps the vessel and wipes out all the electronics except for the handheld GPS and VHF radio.

 They finally clear the cabin of water, and they are still able to sail, but the autopilot no longer has a power source. Reluctantly, they resign themselves to alternating two-hour stints at the helm until they reach the next port 1,200 miles away.

Another scenario is the autopilot simply breaking down a few thousand miles into a voyage, requiring parts and technical expertise rarely found outside the developed world.

Imagine the time, expense and headache that could be saved by installing a well-designed, solidly built wind vane system. Wind vanes routinely survive knockdowns and even capsizes with nothing worse than a broken plywood air vane, easily replaced in less than two minutes underway.

“But my boat has a center cockpit and hydraulic steering. I can’t possibly use a wind vane.” Actually, you will be happy to know there are several models designed specifically for situations where traditional servo-pendulums, such as the popular Monitor, Aries and Sailomat, would be difficult or impossible to use.

“I like the idea of a wind vane, but I don’t want lines weaving across the cockpit.” The Cape Horn, manufactured by Yves Gélinas in Quebec, offers all the advantages of a servo-pendulum but operates below-decks directly on the steering quadrant, leaving the decks clear of steering lines. Other options include designs employing a separate auxiliary rudder, totally bypassing the main steering.

So no matter what type of sail rig or transom configuration your boat has, if your boat’s LOA measures between 20 and 65 feet, there is a wind vane solution for your sailing vessel. Vessels with canoe sterns or boomkins may require a bit more imaginative engineering to design a mounting system, but most wind vane manufacturers have installation plans ready for virtually every production boat in the world’s voyaging fleet.

Types of wind vane steerers
Before settling on a particular type of wind vane, or “vane gear,” you first need to have a basic understanding of what types of systems are available on the market. The most common is the servo-pendulum. This machine uses a thin, flat, vertical piece of plywood or plastic to transmit changes in the apparent wind to a submerged servo-blade via a pair of bevel gears. The servo-blade responds by swinging sideways in the oncoming water and controlling the helm with a pair of steering lines. This is a proven, robust system, and not nearly as complicated as it may sound.

I offer my own vessel and vane gear as an example of the wonders of the servo-pendulum. A Fleming Global 301 steered my 1966 Cal 30 Saltaire 30,000 nautical miles around the earth without a single repair, save a few broken air vanes during severe storms in the Tongan Triangle of the South Pacific and in the Red Sea. To this day, I still do not own an electronic autopilot, although a tiller pilot would be handy for motoring through calms.

A hybrid version of the servo-pendulum incorporates an auxiliary rudder, enabling the unit to totally bypass the main steering system, which is locked while the vane gear is in operation. Peter Förthmann of Hamburg, Germany, incorporates this “double-rudder” system in the Windpilot Pacific Plus and Plus II. He also manufactures two sizes of standard servo-pendulum, the Windpilot Pacific and Pacific Light.
The third type is the trim tab, best known these days as the Auto-Helm, not to be confused with Autohelm autopilots. The trim tab, similar to an airplane aileron, is hinged to the trailing edge of an auxiliary rudder so that the two operate together in lieu of the vessel’s main steering. The helmsman trims the system’s air vane parallel to the apparent wind in the same manner as with a servo-pendulum. The Auto-Helm trim tab and Monitor servo-pendulum are both manufactured by Scanmar in Point Richmond, Calif.

Finally, the fourth type of system is what we may call the “air vane-controlled auxiliary rudder,” known as the Hydrovane and manufactured in Nottingham, England. This system converts wind impulses from a very large air vane directly into steering power through reduction gears. Tom Bridgman of the Pierre Garoff-designed, 40-foot, center-cockpit ketch Axe Calibre (Axmouth, England) told me that on one occasion when the boat was at anchor, he tried to turn the auxiliary rudder manually with the air vane set in about 10 knots of wind. With his arms bear-hugging the rudder and one foot pushing against the transom, he tried with all his might but could not budge the rudder; such was the force as amplified by the reduction linkage.

Emergency rudder capability
Another major advantage of vane gear steering mechanisms is their ability to double as emergency rudders. In the event your vessel incurs loss of, or damage to, the main rudder, a vane gear can provide the steering power you need to reach your next port.

If your vessel is fitted with an Auto-Helm trim tab, Windpilot Pacific Plus or Hydrovane, no adaptations are needed to use the system in place of your vessel’s main steering while under sail. Simply lash the helm or steering quadrant, set the air vane for the desired heading, and let the auxiliary rudder steer the vessel. For motoring, each of these systems may be adapted easily for manual steering.

Most of the standard servo-pendulums, including Fleming, Monitor and Sailomat, can be modified at sea with an optional kit to act as emergency rudders, but because they are not self-contained systems, they must be operated either manually or with the aid of an electronic tiller pilot.

Monitor’s Monitor Emergency Rudder (MRUD) is a large, stainless steel rudder that the operator latches onto the servo-blade shaft after removing the servo-blade. Scanmar also offers a free-standing SOS Rudder, weighing only 35 pounds and capable of steering vessels of up to 50 feet in length. The SOS comes complete with mounting hardware and a tiller, which may be controlled with an electronic tiller pilot.

Fleming offers a bolt-on rudder extension that connects to the servo-blade. Anyone using this system in rough weather will have to keep an eye on the various parts involved during assembly. Though I have never used this emergency rudder on my own Fleming vane gear, the system appears to be well designed and up to the task.

Sailomat’s Blade Extension for Emergency Steering (BEST) is a wing-like foil doubling the area of the servo-blade. According to Dr. Stellan Knöös, who has designed all of Sailomat’s vane gear systems since the late 1960s, the BEST has been qualified as an emergency rudder in a number of ocean racing events where this valuable piece of safety equipment is required for entry.

The underlying principle behind converting a servo-pendulum into an emergency rudder is fairly simple. First install the modified or substituted foil to the servo-blade shaft. Then stabilize the main shaft so that it does not swing laterally. Generally this involves nothing more than tying the steering lines to a pair of cleats. Finally, depending on the model, attach a handle, an extra pair of steering lines or a tiller pilot to the swiveling air vane base, and your emergency rudder is ready to steer.

Getting the right fit
Matching a wind vane steering system with your vessel takes some careful consideration. The main variables you must take into account are your boat’s main steering, cockpit location, transom profile and LOA.

The easiest vessel to accommodate with vane gear steering is a 35-foot sloop with tiller steering, an aft cockpit and a flat or slightly raked transom. This conservative vessel design can accept every type of vane gear available on the market, including a Hydrovane, which would be a bit large for a 28-footer.

A more difficult challenge would be a vessel of 50 feet with a canoe stern and hydraulic steering. Forget about a servo-pendulum in this case. Consider instead the Hydrovane or perhaps the Windpilot Pacific Plus II, each one very different from the other but equally useful where you must totally bypass the main steering in favor of a self-contained auxiliary rudder.

Other options exist for situations where traditional servo-pendulums are impractical. The Cape Horn, because it may be configured to operate directly on the steering quadrant, is but one possibility for boats with center cockpits.

Another option is the Auto-Helm trim tab, available in two different packages. The more popular option is the complete auxiliary rudder system. For those who want to save money on the auxiliary rudder and trim tab, there is the option of purchasing only the air vane servo-head and then building the two hydrofoils at home, incorporating – we would hope – appropriate NACA foil shapes for reduced drag and optimal steering response.

In the case of a transom-mounted main rudder, a home-built trim tab connected to the main rudder’s trailing edge and controlled through cables by a remote Auto-Helm air vane head is the obvious choice where a trim tab is desired. If your vessel has an arch over the stern, install the Auto-Helm head in the middle of the arch between the solar panels or among your array of antennas, taking care to allow enough lateral swing room for the air vane.

For owners of vessels with canoe sterns, boomkins or transom ladders who prefer the power of a traditional servo-pendulum, fear not: as long as you have an aft cockpit and either a tiller or a wheel with cable or bevel gear linkage, there is a way to couple your choice of vane gear to your vessel’s transom.
Aries, Fleming and Monitor all use mounting tubes in their installation. Therefore, for mounting to a canoe stern, it is simply a matter of extending the tubes far enough to accommodate the elongated stern. The closer the lower mounting tubes come to the waterline, the more weight-bearing and torsion-resisting capacity they have.

A boomkin may appear to be forbidden territory for a vane gear, but don’t be fooled. Adapters crafted from stainless steel plate and tubing can be custom-built to accept almost any vane gear design. You can expect to lay out a few extra bucks for an unusual installation, but wind vane manufacturers are highly competitive and innovative in their zeal to please clients with solid mounting designs.

 One of the most creative mounting concepts to come along in recent years is Scanmar’s SwingGate, which they have carefully engineered to couple a Monitor with a swim ladder over a sugar scoop transom. The Monitor becomes a gate that may be swung open while at anchor to enable use of the swim ladder. Sound impossible? My friend Tony Williams and his fiancée Mitsuyo left San Francisco on a Catalina 42 fitted with a SwingGate and crossed the Pacific to Australia with nary a hitch. The SwingGate is definitely what I call “having your cake and eating it too.”

Making the decision
Today the world of yachting is awash with new money and skippers with little or no offshore sailing experience. Many modern sailors feel comfortably secure extending a finger to poke a soft, rubberized button on an ergonomic keypad, delighting to a reassuring “beep.” It is understandably difficult for them to contemplate hand-steering in a full gale while crossing the Atlantic in January. Just imagine the diesel engine pooping out 500 miles into a 3,000-mile sail from Lanzarote in the Canaries to Martinique.

The more we appreciate the raw reality of offshore voyaging, the more we prepare for things that should not go wrong, but do. If you are preparing for a major ocean passage on a sailing vessel single-handed or with short-handed crew, you will have a greater chance of success by depending as much as possible on mechanical, rather than electronic, systems. Foremost among your concerns should be your vessel’s self-steering. The wind vane self-steering systems covered in this article have all been in production for at least 30 years, some nearly 40 years, and all have performed well through multiple circumnavigations.

When sailors and marina visitors see the vane gear on Saltaire’s transom, they know they are looking at a vessel that has “been places.” Vane gear on your vessel’s stern is a trophy distinguishing you as part of a small, elite corps of adventurers who dare to leave the familiar environs of coastal sailing and “go beyond.” 

By Ocean Navigator