November 3, 2006: Look Ma, No Hands! (Wind Vane Evolution)
by Michel & Jane DeRidder

In the late fifties we were building our 24-foot midget ocean racing class (MORC) sloop when we noticed an article in an English yachting magazine telling how Blondie Hasler and Ian Major had both been experimenting with wind vane-powered self-steering devices to use in single-handed Atlantic racing. Curiosity piqued, Michel began a correspondence with them. He was thus launched on a half-century-long series of experiments - cogitating, devising, building, testing and improving wind vanes. The first consisted of a simple trim tab, hinged directly onto an auxiliary rudder powered by a dacron-sheathed vane built like the wing of a model airplane. An old letter from Blondie Hasler reads, "I think that you are the only person I have heard of who has used an auxiliary rudder turned by a trim-tab. Previous auxiliary rudders have been turned direct." This prototype contraption handled the boat more or less, but needed help sailing under spinnaker, at which times it was overpowered. Bug-eyed onlookers looked askance at the vane on the stern of our vessel. We said in answer to their mystified questions, "We're trying to grow a yawl." A British friend chided us saying, "That is the height of sloth."

Then, when building 40-foot Magic Dragon, Michel realized we'd need a far more powerful system. A Eureka moment! He emerged from the shower one evening with the exciting idea of putting the trim tab on extension arms for greater power and leverage, instead of directly on the trailing edge of the auxiliary rudder. When we launched Magic Dragon in '64 there was a long narrow trim tab on 2-foot extension arms on a dedicated auxiliary rudder aft of the main rudder, the auxiliary rudder able to turn 360 degrees so that when reversing it would not interfere with steering. Like the early version, this one had a Dacron-sheathed vane, and this too was aerodynamically foil-shaped like the earlier one, but had a greater leverage arm on the vane itself. The vane we engaged to the trim tab with a V-belt clutch activated by means of a ski boot off-centre lever clamp. The trim tab could also be operated by tugging a line that ran all the way around the cockpit, giving us hand power-steering anywhere in the cockpit. That simple setup worked well for many tens of thousands of miles and countless passages long and short, freeing us from the tyranny of the helm for a good many years.

Power steering with a string.

As time went by, Michel tried other improvements. A remote control system using a bronze toothed-gear dog-clutch mechanism allowed us to change course from the shelter of the cockpit. The crown and worm gears available had a steel worm running into the bronze crown. We could not use the steel gear but were fortunate to have a friend with a first class machine shop. He instructed Michel on the intricacies of machining this complicated bit of gear in bronze and allowed him to do it himself. Somewhere along the line, when our vane's Dacron cover needed replacing, we instead used sheet aluminum to form the airfoil. When kept waxed, it seems to last forever.

Wind vane - old vertical pivot.

Eventually we replaced the original rudders, and Michel decided this was his opportunity to experiment with something that had been bubbling in his brain for years. Why not put the trim tab on its leverage arms on the LEADING edge of the auxiliary rudder? The advantages were several fold The effort of the trim tab helps to steer the vessel, and acts like a balanced rudder, minimising the torque requirements, providing huge additional power and sensitivity. The power was phenomenal, the sensitivity frightening. On an early trial run to figure out the feedback requirements with temporary mountings, a C-clamp gave way. The sudden turn nearly threw both of us overboard when Magic Dragon swerved in its own length at seven knots. We christened the system "Cujo" after Stephen King's mad dog. When Cujo was de-fanged and tamed, we decided to try a flip-flop vane instead of the simpler but larger and more cumbersome vertically pivoted vane. The horizontal pivot vanes have the ability to provide more rudder angle with small drifts off course.

Horizontal pivot.

The original larger main rudder had been the forward rudder; the auxiliary rudder on the stern was slightly smaller. In the present configuration the forward rudder is now the smaller one. Positioned just aft of the propeller, it gives good maneuverability under power, and can be used independently as an adjustable skeg. The aft rudder, with its trim tab, is now the bigger rudder. Both of them can be linked together with an above deck connecting rod and a choice of ratios between the two, or they can be used independently. The connecting rod can be used as a direct mechanical attachment, or it can be used to control the aft rudder via the trim tab providing superb power steering effect. This last feature gives a nice light feel of the boat while steering with the tiller, and it is ideal to use with a small tiller autopilot with low current drain. Our Tiller Master takes 0.3 amps when it is running, and it runs a fraction of the time, depending on sea conditions. Although tamed and very effective, the rudders can still be used to steer the boat wildly if we choose to. We can, for instance, do a fast 350 degrees into the wind rather than gibe our fully battened mainsail, and we can spin Magic Dragon on the spot to clean a muddy anchor by towing it sideways from the bow. We still have our power steering line around the cockpit, giving us the option to steer from our pilot seats or from anywhere in the cockpit - lee side, weather side, forward or aft - without any expensive, cumbersome double wheel with the associated complicated mechanisms.

These days many cruising yachts do not have self-steering by mechanical wind vanes, relying exclusively on one or more electronic self-steering devices, often entirely successfully and with some incredible course automation. We use our electronic pilots when there is no wind and we are making tracks under power. Our old Wood Freeman fisherman's hunting auto pilot wags the tiller back and forth, drinking 12 amps as it steers. We use Tiller Master under sail when exactness of course is of ultimate importance - as when landfalls are imminent or when we are coastal cruising and a wind change could endanger the boat. But at sea, on long passages we sail by the wind. The wind vane is tireless and it does not deplete the battery. It makes no noise. It responds to wind shifts so that the crew does not need to be alert to making sail adjustments. The sails can be trimmed when a course change is needed. Our wind vane can be depended on to keep us safe from jibes or to tack for us. It can be set to peel off down wind while we reef or do other chores on deck in strong wind. It would not be affected by a failure in the electrical system. Electronics can and do fail. When shorthanded, it is important to have some backup form of self-steering, unless the vessel is able to steer itself, which some boats do better than others by means of sail adjustments. The fast multihulls that accelerate rapidly, and for which the apparent wind can vary greatly on the same heading, cannot be successfully steered by a wind vane, but because they are so responsive to the helm, they can be handled by an electronic pilot. Vessels with a sizable crew often do not bother with an automatic pilot, preferring the discipline of watches and steering by hand. In the early days, we noticed many wind vane systems, some of the earliest being the Hasler and the Aries. Nowadays the most popular seems to be the Monitor.

Wind vane power steering connection with the rudders' connecting rod pinned up onto the trim tab control drum.

Not being of technical bent, I have not always grasped all the complexities and options of our latest wind vane systems. Now and then I look back nostalgically on the simplicity of my old ski harness clamp on the V-belt clutch of our early days.