How Servo Pendulum Self Steering Windvanes Work

[John Stone]

I put this video together for those interested in how a horizontal axis servo pendulum windvane works. While much of the info is specific to a Cape Horn the working part is the same for Cape Horn, Monitor, Aries Windvanes.

https://youtu.be/8upov7LwLtk?si=CDHtL8F6EsrBcEMR

[fmueller]

Thanks for posting John ... fabulous video ... !!

I keep toying with the idea of a vane on my 27. I don't think I'd want to have the Cape Horn (elegant as it is) due to the impingement thru the lazaret although that keeps above deck lines to a minimum. The next best aesthetically by my eye are the Wind Pilots. Do you have any knowledge of their performance? It seems they are in wide use - so that's an observational plus vote.

cheers

Fred

[John Stone]

Fred, I don't have any experience with the wind pilot but they are expensive. They have different kinds of metal in them, which I think is generally a bad idea, and the videos I have seen of them the aluminum is always corroded.

On a 27 especially if I wasn't planning to cross oceans I'd look around for a navik. They are fairly inexpensive and a bit smaller than the wind pilot and monitor so it will look more proportional and at home. They have a reputation for being capable. I am not sure if they are still in production but I see them for sale all the time.

You might reach out to James Baldwin and you can use my name as we have an established relationship. He is very familiar with the Navik or might even offer you other ideas. He has more experience with offshore boats under 30' than anyone I know. You can find him at atomvoyages.com.

[fmueller]

thanks John ... I did communicate with James last summer ... amazing fellow and history ... he has installed a few Wind Pilots ... likes them well enough ...

[John Stone]

Well there you go. James is a smart guy so if he thinks it's a good vane that would carry some weight with me.

[Paul D.]

The Hydrovanes are widely used in the around the world races and won the Golden Globe last year (However another one did break fatally for the unit in a knockdown off Cape Horn. I think it was the actual shaft for the wind sail and the skipper didn't have spares.) If I couldn't use a Cape Horn windvane - they were literally designed for our boats - I would probably look at the hydrovane. Easy to install, don't create a maze of tubes hanging off the transom, pretty robust and has the advantage of acting as an emergency rudder. I wonder how much more drag they would create though with the bigger paddle. Either way they are still being made, there are a lot of them about and the design seems pretty proven. But I hear first hand nothing steers like a Cape Horn downwind and having had my hands on them, they are at once robust and elegant... I think I would just go Cape Horn. Screw it.

[John Stone]

One of the things I don't like about the hydrovane is the different metals used. Plus they don't steer well down wind from what I have read. The power in a servo blade is incredible. I'd go with a monitor before a hydrovane. Monitors are hard to beat. Very similar in mechanics to the CH just not as elegant. They had some reliability issues with broken servo shafts for a while but they created a reinforcement kit which I believe solved that problem. I think Jim Walsh has been very happy with his monitor vane.

Something no one is talking about is which vanes are actually getting used day to day. What I mean is lot of boats have windvanes on the stern but my own observation is they get little to no use. The owners instead rely on an electric autopilot. Is that because the vane does not work very well? Hard to employ? They don't know how to balance the helm and the vane performs poorly so they go with an autopilot? In fact, I don't think I have ever seen a boat sailing with a windvane with my own eyes. Usually, it's auto pilots.

Deep winter up there in MI Paul. How has it been so far this year?

[Jim Walsh]

Like Steve Laume I am a big fan of the Monitor. It has never failed me and is the main reason I can cruise long distance. When I bought it new I purchased the “cruising spares” kit but I’ve never had to use it so far. I make use of the Monitor extensively even when daysailing close to home. It takes just a moment to engage and disengage and saves me from the “tyranny of the tiller”, or in my case the wheel.
Even on trips to Bermuda I go for days at a time without even touching the wheel. On my last passage down and back I had the best weather I’ve ever experienced. I may have been at the helm for a couple hours over a five day trip down and back and that was while leaving my slip and at the arrival to St. George’s harbor.
As far as “elegance” goes I’m a big fan of robustness and proven capability. In my minds eye that is the true definition of elegance. Zero power consumption is ideal for smaller yachts. The below deck electric autopilots seem to have proliferated along with the vast increase in the average size of cruising yachts since the late seventies. It takes a big battery bank to power those units over an offshore passage and power regeneration becomes a prime concern. Keeping a spare drive unit on hand, and the ability to switch out a faulty unit under adverse conditions, is mandatory, unless, of course, you are fully crewed. I am speaking from the point of view of a singlehander.
My Cape Dory moves me from point A to point B safely and comfortably, and my wind vane self steering unit ensures I do so efficiently and well rested. I am a big fan of both!