Monitor Windvane

Monitor Windvane

Special Features

316 L (Low Carbon) Stainless Steel Construction
No Aluminum = No Corrosion

The most unique and valuable feature of the Monitor is probably the materials from which it is made. Almost the entire Monitor is made of TIG welded 316L stainless steel which is electropolished after the welding process.

Stainless is a difficult and expensive material to work with, but corrosion is avoided. The thin wall stainless tubing with large diameter combines great strength with comparatively light weight. Everything is easy to take apart and, in the unlikely event of damage, repairs are usually possible at sea or in remote places with regular hand tools.

Many other windvanes are made in aluminum, which in our opinion is an inferior metal when mixed with other metals and the environment is saltwater. Aluminum castings are more "production friendly", which explains their popularity. They come out like "cookies" from a mold and the material is soft to machine. All you have to do is to drill one hole in stainless and one in aluminum and you know the difference. Unfortunately, you have to put aluminum castings together and you have to use stainless fastenings and shafts for strength. Now you have galvanic action and a corrosion problem. Just look at a boat that has been out to sea for a few years, cleats and winches on an aluminum mast, for example. Corrosion can be avoided by insulation to some degree, but it still requires that you take the unit apart on a regular basis and use special lubricants or inserts. If an aluminum gear is not taken apart and serviced, there is a good chance that it will be more or less impossible to take the entire gear apart later on. If you have a collision and crack an aluminum casting, do not try to weld it. The part should be exchanged for a new casting. However, you might not be able to take the unit apart because the stainless fastenings might be "frozen" to the aluminum goods. In contrast, 316L has no corrosion problem and can always be taken apart. Stainless can also be worked and welded locally if the unit has been in a collision.

Superior minimum friction, ball and roller bearing system.

The Monitor airvane pivoting unit has two sets of delrin ball bearings in stainless steel races. The pinion gear has two sets of delrin roller bearings and the pendulum shaft has top and bottom delrin roller bearings in stainless steel cups. These bearings make a tremendous difference especially in difficult windvane conditions, which is light air and downwind when the apparent wind is very weak. The airvane has very little power in these conditions and friction in a windvane will kill performance.

In an effort to cut costs we made a Monitor prototype with delrin bushings, (as used by many other windvane manufacturers), rather than ball and roller bearings. Now we could test two Monitors, identical except for bushings instead of proper bearings. When we set up the two units side by side, the difference between the prototype and our standard Monitor was so apparent that we did not bother to test sail the prototype. Our test was over in 5 minutes but it was a valuable confirmation of how important our more expensive bearing system is.

Performance is our first priority - and we never compromise

Our bearings are loose rather than caged. Caged bearings would collect dirt and salt deposits and require maintenance just like your winches. The Monitor delrin bearings should never be oiled or greased. Oil would gum up the bearings when the grease is mixed with saltwater. An occasional fresh water hosing helps but normally rain takes care of this. The Monitor is basically maintenance free and you can expect to do an entire circumnavigation without taking the unit apart for service.

Design of the master gear set

The Monitor gear set consists of the pinion gear (top) and the ring gear (bottom). The gears are designed with a feedback mechanism to prevent the Monitor from over steering and "fish tailing". The maximum correction happens when the gear is in neutral position. When the pendulum swings to the side, the rotation of the pendulum is gradually decreased. The gear set is investment cast (lost wax method), which is far superior to sand casting. They are made of 316L stainless steel, as is the rest of the Monitor.

Positive yaw dampening

When you are running downwind in big waves and strong winds, there is always the chance of a broach when the boat is surfing. This is normally prevented when the Monitor is steering because of a feature called "POSITIVE YAW DAMPENING". The problem is that the wind is blocked by the following wave and no signal is reaching the airvane when the boat is starting to go off course. Now Positive Yaw Dampening comes into the picture.

If the boat starts sliding sideways, the start of a broach, the Monitor water paddle will be pushed in the opposite direction to the boat. You can also say that the water paddle is stuck in the water and the boat moved to the side. The result is an instant correction of the course because the water paddle moved in the correct direction. The wheel will spin and the broach is prevented. The signal to correct the course this time came from the water, not the air! It could also be a combination of the two. Positive Yaw Dampening is your broach insurance. Needless to say, the skipper might consider shortening sails before it happens again. Many other windvanes do not have Positive Yaw Dampening.

One to one movement on pendulum lines

In almost all installations the Monitor uses a simple one-to-one movement of the pendulum lines. The direct movement is possible because the line attachment on the pendulum is located far from the pivoting point. This distance is 18 inches (46cm ). Other windvanes have a distance to the line attachment which is much shorter, often less than half the length of the Monitor. On such windvanes the lines normally do not move a sufficient distance when the pendulum swings to the side and the wheel will not turn enough. To get enough line movement and turn the wheel sufficiently, such windvanes use a so called "reverse purchase" or "fool;s purchase" to get 1:2 or 1:3 ratio. To get this movement a complicated block system has to be installed between the windvane and the wheel. The number of blocks can vary but as many as seven blocks seems to be quite common. Monitor installations only need blocks to connect the windvane with the wheel. No additional blocks to get more movement of the lines are needed. Fewer blocks between windvane and wheel result in a cleaner look. It is also less complicated and causes less friction.

Built-in block alignment of the pendulum swing

To transmit the power from the swinging pendulum, the Monitor has built-in blocks in direct line of the swing. They are located at the bottom of the "legs" of the frame. It should be noted that on some windvanes with the pendulum lines attached to a short staff ABOVE the pivoting point extra blocks are needed to transfer this movement. On many boats this is not possible without special attachment points for the blocks on both starboard and port side. The direct swing line of the staff is too far aft of the deck or the stern pulpit.

Strong four point mounting system. Custom designed and fabricated tubes for each boat at no extra cost

This is especially valuable for boats with open transom, canoe stern, low freeboard, transom steps, swim platform, outboard rudder or boomkin. Rather than concentrating the entire load to one single area, the Monitor mounting system disperses the load to four points on the boat. If you compare cost of different windvanes we suggest that you compare the cost of the windvanes INSTALLED. We will supply the entire stainless mounting system for YOUR boat, custom designed and fabricated! This will most certainly save money and more importantly, give you guidance to make a correct installation.

Gear for a Lifetime

The unique mounting system of the Monitor means that it can easily be transferred from boat to boat. If you decide to change your boat you can take your Monitor with you. We would recommend that you leave your brackets on the boat thereby eliminating the need to fill the holes! Sometimes the old tubes can be used again. The cost to remount a gear is often less than $200.00. You might also need a different safety tube.

Custom Spectra Pendulum Rope

This 1/4" inch rope is custom made for the Monitor and included in the price. It has straight (not woven) SPECTRA on the inside to minimize stretch.

The outside is polyester which will protect the line from wear. You can do a complete circumnavigation if you make sure to periodically change the places that chafe. Just pull out a few inches at the pendulum, make a new knot, cut off the stump and discard it.

Light weight and easy to take off

Because of the use of stainless tubing we can achieve light weight, only 52 pounds or 24 kilo. Large diameter tubing, 1.9 inch diameter or 50 mm., with thin wall thickness will combine strength and lightness. Some sailors prefer to remove the Monitor when in port for a longer period. This is easily done by removing the four bolts that hold the Monitor to the mounting brackets, which are left on the boat.

Infinite (stepless) and remote course control

This feature is standard on Monitor. Rather than having the course setting in increments of degrees as some windvanes do, the Monitor can be fine tuned to the smallest adjustment. Upwind you can set it so it will steer closer to the wind than an expert sailor and follow every wind shift. Down wind you can fine tune it to go exactly in the direction you want to steer.

The remote control makes it possible to adjust the course from the safety of the cockpit, or even from under the dodger when the weather is nasty. You can avoid putting on foul weather gear to go on deck to make a minor adjustment. A windvane is sometimes hard to reach on boats with reverse transom, outboard rudder or when mounted on a boomkin. On such boats remote control is an absolute must from the safety standpoint.

Stainless steel servo blade

The Monitor servo blade is engineered like the rest of the Monitor, in stainless steel. The stainless steel shaft goes almost to the bottom of the paddle and is plug welded to the outside stainless steel skin. The paddle is semi balanced and has been given a NACA high lift profile to allow the airvane to easily turn a larger surface in lighter air. The inside of the paddle is filled with closed cell, high density foam which gives it tremendous strength. To test the strength, we ran over the paddle three times with our large Dodge Van and nothing happened to the paddle. Of course it is unlikely that you will hit a Dodge Van on your world cruise, but you could hit a floating object in full speed and it is good to know that the Monitor paddle is extremely strong. To get maximum power the paddle is not inclined, it is vertical. It is our opinion that the vertical paddle is more efficient and spade rudder designs on race boats confirm this theory.

Overload protection

Between the hinge and the water paddle is the safety tube. This is an inexpensive sacrificial stainless tube designed to buckle in case of an overload from a snagged lobster pot, tree stump, violent broach, or a collision. The exposed portion of the tube is much weaker than the hinge or the water paddle. An extra safety tube is included in the price but the chance that you have to use it is very small. The Monitor safety tube is designed to work with impact from any direction.

Remote flip up/down paddle - Superior hinge and latch design

This is absolutely one of the best features on the Monitor. On many other brands it is impossible to take the paddle out of the water at sea and on others it is very difficult. With most of them you can only do this when the boat is stopped and not moving! The Monitor latch mechanism locks and unlocks the hinge. It is designed to lock harder and harder as pressure on the pendulum increases with speed. It does not open if you hit an object since the windvane could not differentiate between hitting an object and sailing very fast. We have had BOC boats reach speed of 25 knots with the Monitor still steering. It would be disastrous if the latch released in a wild surf while the boat is still more or less under control. It is the safety tube that is designed to fail in an overload situation.

You take the Monitor paddle up with a simple pull on the release line and pull it out of the water with the safety line. This can be done easily and safely without touching the Monitor - even in the dark and while the boat is moving, at any speed! To put it down you simply release the safety line and when the paddle drops in the water the latch will close automatically. If you go faster than appr. 4 knots you should luff the boat for a few seconds to slow the boat down and the latch will engage. The ease of this maneuver makes it possible to put the paddle in the resting position as soon as it is not steering your boat. The Monitor servo oar should only be in the water when it is steering and this will contribute to the longevity of the Monitor. On boats with an outboard rudder, the windvane is more difficult to reach. This feature then becomes even more important since safety is involved.

MRUD—True emergency rudder conversion kit with a rudder large enough to steer a 50 ft BOC boat

As mentioned previously, we prefer the servo-pendulum system for normal self-steering. In the unlikely situation that the boats main rudder is broken you can convert the Monitor to a true emergency rudder with the optional MRUD.

Pendulum Guard

Since 1991 every Monitor has a strut guard, which is a piece of tubing that connects the bottom of the legs of the Monitor with each other. They have been added to protect the Monitor from impact if a boat accidentally would drag backwards or be hit from behind. In addition, the strut guard also makes the entire installation enormously strong and has permitted the development of the MRUD.

More about MRUD