Many of today’s offshore cruising sailboats utilize a type of autopilot equipment called a windvane. A sailboat wind vane is a mechanical self-steering system that requires no electricity, fuel, or manpower to operate. It’s the perfect addition to bluewater cruisers and offshore sailboats. While a mechanical self-steering wind vane can’t hold you on a compass course, they’re more accurate than human steering over long distances. By reducing the overall mileage of a passage, you’re able to save time and money on your journey. Alternatively, a windvane is essential for short-handed or single-handed sailing. It gives the skipper a much-needed break from the helm when conditions allow.
How Does a Wind Vane Work on a Sailboat?
Mechanical wind vane systems are relatively simple in concept. Once mounted at the boat’s transom or somewhere along the stern, wind prompts the elevated vane to adjust the rudder or wheel steering system, putting your sailboat back on a wind-based course dictated by the captain. The idea is that you won’t have to make constant adjustments in variable winds. Automatic adjustments reduce boat heeling and allow your vessel to remain trim in the water.
In other words, wind vanes use wind and water resistance to return a ship to course when wind chages direction.
Sailboat Windvane Gears Vs. Electronic Autopilot Systems
Two primary self-steering systems are standard for bluewater cruisers and offshore sailboats: wind vane steering gears and electronic autopilot systems. Both systems have advantages, and many sailors choose to install both systems on their boats.
Electronic Autopilot Systems
Electronic autopilot systems are the modern answer to self-steering. They’re easy to use, work without wind, and are an excellent option for near-shore cruising and short-term offshore sailing. Autopilots are also compatible with multi-hull vessels, unlike windvane systems.
The downfalls to these systems can be daunting, though. Electronic systems are complex and have numerous parts: displays, wiring, plotters, motors – the list goes on. To run an electric autopilot system, you’ll also need a generator. Most even have two generators, using one as a backup for reliability. As you’d expect, they also come with a higher price tag.
Self-Steering Wind Vane Systems
Windvane steering systems take a more traditional approach to self-steering. They rely on the wind to operate your boat on the desired course. Wind vane steering systems require no electricity, little maintenance, have few moving parts. They also come in several variations to fit your boat in the best way possible. Another massive benefit of a mechanical sailboat windvane is its robust build. This allows reliable and powerful performance in heavy weather conditions.
There are also several downfalls to a windvane system. They do not work in the absence of wind or under power, can add weight and stress to the boat stern, can be initially expensive to purchase, and won’t work on multi-hull vessels.
Types of Sailboat Wind Vane Systems
All wind vane systems direct a boat to a wind-based course, but they each do it differently.
Servo-Pendulum Wind Vane
Servo-pendulum windvane systems are the most common commercially available system, and they are a favorite among most sailors. The reliability for offshore sailing is a huge selling point. It re-affirms why these are the “classic” wind-driven autopilot systems.
Main steering servo-pendulum systems have control lines running from the primary steering quadrant to a wheel or tiller. As the wind pushes the pendulum, it directs the boat’s steering by way of the primary rudder. Because of this, the system is solely dependent on the power of the wind. The stronger the wind blows, the more force the system provides to push the boat back on the desired course.
Rudder steering servo-pendulum systems have the pendulum rudder connected to the primary boat rudder. It works almost the same as the “main steering system,” with a few minor differences. The wind pushes the pendulum rudder to the side, forcing water to pull the boat’s main rudder to change steering. The advantage of this system over the prior is that it involves fewer mechanical components, making it easier to check issues and fix any problems. The disadvantage is that it can be a bit trickier to set.
One of the biggest downfalls of either servo-pendulum system is that the pendulum rudder can not replace an auxiliary rudder. Unlike an auxiliary rudder, its one-dimensional operation makes it unable to run the system if the primary rudder fails. These systems can also create a cluttered cockpit due to the lines running from the steering quadrant. Lastly, servo-pendulum systems generally require more consistent maintenance and more common repairs.
Auxiliary-Rudder Wind Vane
Unlike servo-pendulum steering systems, auxiliary-rudder wind vanes are entirely independent of all other aspects of the boat. Instead, the main rudder is locked, and the auxiliary rudder steers the vessel after setting a powerful windvane to the desired angle. The main rudder is often locked to the left of center or slightly at an angle to balance the helm. One of the most significant advantages to these systems is that if the primary boat rudder fails, the auxiliary rudder can act as a replacement to steer the boat.
There are some important considerations to make when purchasing auxiliary-rudder wind vane steering gear. First, auxiliary-rudder windvanes put a significant amount of stress on the vane, making it vital that the model and components are well designed and made of quality materials. If you can source well-made parts, there is minimal risk while out at sea. There are very few moving parts and no critical lines attached to the system. Second, these systems are big, heavy, and bulky. Having such a massive piece of equipment at the stern of the boat isn’t always ideal in every scenario. Lastly, auxiliary rudders can be awkward to operate when the mizzen is in use on ketch-rigged vessels.
Trim-Tab Wind Vane
Trim-tab windvanes are less common than they used to be after the emergence of the steering technologies listed above. The system works by attaching a “tab” to the main rudder. The small surface of the trim tab makes it easy for the wind to move it from side to side, which then forces water over the primary rudder in the opposite direction to keep the boat on course. Those with the appropriate skills and know-how can even construct a trim-tab themselves, although we recommend that they do not rely entirely on a self-made system.
The major drawback to trim-tabs is that the ability to fine-tune the system is somewhat limited in heavy conditions.
How to Install a Sailboat Wind Vane System
Installing a wind vane on your boat is relatively easy, but it still takes a bit of planning.
All windvane models require installation at the center of the boat’s transom or as close to the center as possible. Depending on which system you choose to run, you may need to account for the steering lines that operate the system. Steering lines are approximately a quarter of an inch in diameter and need a clear path from the wind vane to the boat wheel. You may redirect the lines with steering blocks, but be aware that each block adds friction and lessens the overall efficiency of the steering system.
Balancing the Boat
Windvane gears adjust the course of a boat using the wind force at the surface. For this to happen efficiently, you’ll first need to ensure your boat is balanced and sailing as intended. Take your time to get the weight distributed evenly. You’ll also need to reef the sails appropriately so as not to be overpowered.
Adjusting the System for the Conditions
Regardless of the system, nearly all sailboat wind vanes have one or more adjustment features so that you can optimize performance in various conditions. When wind conditions are relatively light, you should expose the vane as much as possible so that the system receives the most force as possible. In heavy winds, however, you can lower the windvane to reduce the impact on the system. In some cases, the wind vanes have sensitivity adjustments where the vane meets the pivot, so you may not need to adjust the height as weather conditions change.
How to Engage a Sailboat Wind Vane System
Most wind vanes are relatively adaptable and can adjust to fit a variety of hull types. Some vanes are even customizable to bolt directly onto the boat. As with any other object you bolt to your hull, plan to through-bolt everything with the appropriate bedding and backplates for maximum security.
Operating a sailboat wind vane is far less complicated than you might expect. There are four standard steps to engaging a windvane:
- Deploy the Gear: To do this, attach the wind paddle and unfold the rudder to be placed in the water. Doing this should only take a few minutes at most.
- Connect the Control Lines: Control lines run from the windvane to the boat wheel and may have steering blocks included in the setup. The system may require you to make a few knots or use some hardware, but again, it’s a relatively easy process once you’ve completed it once or twice.
- Balance the Boat and Set a Course: With the wind vane deployed, balance your boat, set the course to the desired point of sail, and adjust the windvane to engage the steering.
- Evaluate the Course and Adjust as Needed: Adjust the vane to steer more accurately after evaluating your approach. Course adjustments are made by rotating and trimming the paddle to match your course.
Perfectly balancing your boat is one of the easiest ways to make your self-steering wind vane more efficient in the water. A vessel with poor balance or trim will not just sail inefficiently, but it will put unneeded stress on the wind vane system.
Have more questions about sailboat windvane systems and how you can best implement them on your boat? Reach out to the #Boatlife community on our forum with questions or comments!
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Jos Jacobs says
Thanks for the useful information. However, you didn’t mention anything about the usefulness of wind vanes in light or downwind sailing. You mentioned the issue of a mizzen and auxiliary rudder, how do I understand that (as we sail a ketch and thinking about installing a Hydrovane.