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Wind vanes refined

Oct 24, 2013

Newest developments in wind vane self-steering technology

(page 2 of 4)

Dr. Stellan Knöös is one servo-pendulum wind vane designer and manufacturer who never sleeps. From his first creation, the self-contained Sailomat 3040 servo-pendulum and auxiliary rudder that debuted in 1974, to the pendulum-only 536, 601, 700, 701, and then 760 released in 2008, Knöös continues to obsess over the most minute details in foil design, his patented “spherical-joint” systems, alloys, manual controls, and on goes the list.

Courtesy Cape Horn

A Cape Horn unit mounted on a Beneteau First 38.

Knöös announced his latest design, the Sailomat 800, an updated version of the 760, will be released this fall.

“The overall features of the Sailomat 800 are similar to the 760, with less weight and a more efficient and lighter servo blade,” explained Knöös. “Overall performance is improved, mounting is very simple, and it’s priced about the same as model 760. And naturally, the 800 is covered by a U.S. patent.”

The 760 and 800 both feature a polycarbonate airvane, lightweight marine aluminum construction and an adjustable, easy-to-remove base mount that fits any transom angle and requires no mounting tubes.

Knöös makes his home in sunny southern California, but continues to manufacture the Sailomat in his native Sweden. While he still manages the daily business operations, he is now looking for a “partnership in marketing and sales,” allowing him the opportunity to focus “solely on the innovation and engineering side.”

If you have seen only three vane gears in your entire life, one of them was probably a Monitor servo-pendulum, built by Hans Bernwall and design director Ron Geick at Scanmar International near San Francisco. Their market presence has grown from many years of producing a simple, strong, straightforward servo-pendulum design.

Sturdy silicon bronze bevel gears once served as the heart of the Monitor’s servo mechanism, joining the push rod with the servo blade. That was until Geick noticed that a prototype set of precision-molded stainless steel gears, with their tighter granular structure, moved more smoothly and were less prone to wear than the bronze gears. The Monitor’s first batch of stainless gears also revealed another advantage: they required no touch-up machining, allowing faster assembly and less delay for eager customers.

The Monitor’s mounting structure also has taken off in a new direction in recent years as new transom shapes demand ever-more creative wind vane mounting concepts. While the Monitor’s underlying design and construction have remained fairly constant since it entered production in the late 1970s, the Swing-Gate, pioneered by Geick in 1999 for Tony and Mitsuyo Williams’ Catalina 42 Windriver, for the first time enabled crew to open the Monitor like a door over a sugar scoop transom, permitting use of the swim ladder.

Marilu and I tried out Windriver’s Swing-Gate when we went for a swim in the anchorage at Tahuata in the Marquesas. The Swing-Gate opened smoothly and easily, with no play in the finely-fitted stainless tubing.

“We designed a newer version of the Swing-Gate for boats with a solid reverse-slope transom with a central drop-down ladder about a year and a half ago,” Geick explained. Not long after this engineering achievement, another customer walked into the shop asking for a Monitor to fit an Outbound 40.

“The boat transom was configured so neither the vertical nor the sloped Swing-Gate mount would work,” Geick continued. “We built a hybrid sloped version that keeps the ladder clear and accessible — it will fit only an Outbound 40. We have an extra set of brackets built and ready for the next Outbound 40 customer who walks through the door.”

In the unlikely event of needing a replacement part for your Monitor, Bernwall has a well-established reputation for his zealous adherence to Scanmar’s warranty policy. No matter where you are in the world, if your little coral island in the South Pacific has a loading dock or a landing strip, he will send warranty replacement parts to get you back under sail in the shortest time possible.  

When 16-year-old Jessica Watson sailed out of Mooloolaba Harbor, Queensland, Australia, on her record round-the-world sail aboard the Sparkman & Stephens 34 Ella’s Pink Lady, she turned the helm over to a Fleming Global Équipe servo-pendulum, which is now manufactured exclusively in Australia. Through good weather and bad, including several knock-downs in 75-knot monster gales in the Southern Ocean, the Fleming vane, constructed of super duplex stainless castings, faithfully kept Pink Lady on course.

One piece of equipment you will see more of in cruiser anchorages these days is a vane gear combining the classic appeal of a varnished hardwood servo blade with a high-tech mix of virtually indestructible marine-grade components.

Light, sleek and attractive, Voyager Windvanes of Cambridge, Ontario, Canada, builds a servo-pendulum self-steerer of Tenzaloy 713 aluminum-zinc-magnesium castings, which offer a high strength-to-weight ratio along with superior resistance to oxidation in a marine environment. The servo shaft and vane mast feature “indestructible bearings and Teflon bushings” and fast, easy response in light airs.

When the wind starts howling, rather than leaning over the stern to switch to a storm airvane, you simply adjust the counterweight to accommodate the increased wind strength.

Voyager’s innovative wheel drum steering adaptor is “activated by a Kevlar belt,” explained company spokesman Gordon Laco. He added, “The drum is infinitely adjustable and is locked by a brake disc design.”

Most installations of Voyager units weigh in at anywhere from 40 to 55 pounds, significantly less than most of its competitors and certainly an advantage on vessels of less than 35 feet LOA. The 12-inch by six-inch mounting footprint with only four mounting bolts eliminates mounting poles and leaves more room for a swim ladder or an outboard motor davit.

Under new ownership by Phil George, the new Fleming Global Équipe series took Kevin Fleming’s original Global series to its next logical step with worm-gear vane mast control, a 35 percent increase in strength-to-weight ratio and a polymer airvane that replaced the former plywood foil.

The Global Auxiliary Rudder, reminiscent of the Sailomat 3040 and the Windpilot Pacific Plus built by Peter Förthmann in Hamburg, Germany, is completely new to the Fleming line. The Global Auxiliary Rudder is a totally self-contained steering system comprised of both a servo blade and an auxiliary rudder. Like all auxiliary rudder systems, the system doubles as an emergency rudder in the event of main steering failure.

The granddad of all modern servo-pendulums is of course the venerable Aries, designed by Nick Franklin and introduced to the world in the 1968 Sunday Times Golden Globe Race. “The Aries is hard to improve,” said Peter Matthiesen, who bought the company in 1992. “Nick always tried and in the end he ended up with the old Aries standard design as the best and most reliable one.”

Matthiesen’s main challenge has been in coping with the latest sugar scoop and reverse transoms with swim steps, a familiar story among vane gear builders. But as for the Aries itself, Matthiesen said in a recent e-mail, “No, I did not change it. The sea did not change, and the boats are still steered by tiller or wheel.”

Another servo-pendulum model is the Cap Horn self-steering gear developed by Canadian circumnavigator Yves Gélinas. The CapeHorn concept uses a single tube that is installed through the boat’s transom. This tube carries enclosed control lines that are connected directly to the boat’s steering quadrant. This approach eliminates exterior steering lines, making for a less cluttered cockpit. And, according to Gélinas, the CapeHorn approach leads to a lighter, less expensive and less obtrusive installation. Gélinas tested his CapeHorn concept himself by sailing a 28,000-mile circumnavigation in the early 1980s with his CapeHorn unit doing all the steering.

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Sep 14, 2014 07:05 am
 Posted by  brunos


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