The best crew member on board is the Monitor windvane. It doesn’t eat, doesn’t sleep, doesn’t complain and steers our boat twenty-four hours a day. What more could you ask for? There are realistically three ways to keep a boat on course. The first one is, of course, the old fashion way where one sits in the cockpit, holds on to a tiller of any kind and steers manually. And, let me tell you, that gets old rather quickly.
The second option is an auto-pilot. It is a device tied into an electronic compass. You set the heading and the rest is taken care of. Take a nap, have a shower, do whatever you want, the boat heads in the right direction. Sounds great, and it is, but what if the wind happens to change direction, what then? Now there is the downfall, it doesn’t compensate for that and in a worst-case scenario you might actually find yourself accidentally tacking or gibing what could lead to damage to boom, sail or other equipment. Still a beautiful tool as long as you keep an eye on it. It also draws electricity and we don’t have much of that.
And then there is the windvane, the third option. In our case a Monitor windvane produced by Scanmar International out of Richmond California. What does it look like? Nothing much really, a few tubes, like a small scaffold called the vane frame, attached to the back of the boat with a little stainless steel rudder, called a servo pendulum, hanging down in the water and an airvane going the other way sticking up behind the boat. The vane is about eight inches wide and four feet tall and has with big bold, but yet comforting red letters, ‘Monitor’ written on it. The two are connected through a connecting rod and gear linkage and the pendulum in turn is connected to our steering wheel through some lines and blocks. Really not much to it and yet so ingenious.
To understand what we are looking at we need to know what a servo pendulum is. It is not something that comes up in a casual conversation and I can’t find the meaning of the word ‘servo’ anywhere in the manual that comes with the windvane. So we go to the internet and find that: a servo mechanism is a powered mechanism producing motion or forces at a higher level of energy than the input level. Okay, I get that. The force of the airvane, happily frolicking in the wind, is not enough to move the steering wheel, but it is enough to move the pendulum which then uses the boat’s own speed through the water as a power source to move our rudder in the right direction. Very clever, very clever indeed.
The manual does tell us that the first Monitor was made in 1975 and that the first decent manual was published in 1982. Pity the people in the years between. It also states that, and I quote, “In order to enjoy the experience of self-steering, the vane gear must, of course, work.” An eye-opener in itself, who knew? In addition, it tells us that it was designed by Colonel “Blondie” Hasler for the early single-handed transatlantic races.
The manual also informs us that the airvane is made of 4 mm, – 4 ply of the finest Finnish birch plywood. I don’t know much, or rather absolutely nothing, about Finish birch plywood, but now I’m thinking that has got to be very high end. Apparently, it is both durable and easily replaceable. However, on a page loosely tucked in the manual called, Addenda for Monitor Manual – March 2008, it says, “Both the large and small airvanes are now made of 8 mm Lexan Thermoclear, reinforced with plastic rod inserts. They are not affected by dampness.” That’s good, dampness is one thing there is plenty of on an ocean.
But how does it work? Quite easily actually. One steers the boat to a desired heading. Rotate the vertical airvane so it stands straight up and then lock the two lines coming from the pendulum in place on the steering wheel. They are always attached to the steering wheel by a small clamped on wheel, but when not in use that little wheel is just freewheeling. When the boat goes off course, or really changes direction to the wind, the vane gets pushed over by the wind and that steers the pendulum. The pendulum then, through its servo mechanism principle, steers the boat back on track and the windvane pops back up again.
So what’s the big difference between the auto-pilot and the windvane apart from that the windvane uses no electricity and that, in our case, the auto-pilot is on the blink and isn’t working at all? Here is the skinny. The autopilot is designed to keep you on a certain compass heading. You set it to 11 degrees, you’ll go on a course of 11 degrees. No matter what the wind does. Unless it dies of course, then you don’t go anywhere. In contrast, the windvane keeps you at a certain angle to the wind. The wind changes direction, the windvane changes the boat’s course with it. No accidental gibes or tacks, no damage to boom, sail or mast. However, because it changes the heading, you could be on your way to Fiji and one day wake up in the South China Sea.
And that’s why we keep watch.
