Monitor Manual
4 Sailing with the Monitor
4.4.2 Light Airs
"Does it work in light winds?"This is a standard question asked of anyone involved with windvanes. Obviously, since the vane gear takes its signals from the wind and its power from the boat’s movement though the water,the wind has to blow and the boat has to move for the vane gear to work.
How little it can blow and how slow the boat can travel with the gear still functioning depends to a great extent on the boat itself, on the skill of the operator, and on the point of sail in question.
If the boat is very large, it will generally take more force from the vane gear to operate its rudder. This is also true if there is much resistance to turning the boat’s steering system. The vane gear has much less power in lightairs, and the key to make it work is to reduce undue binding and friction. Light air performance can be vastly improved by balancing and fine-tuning. In general, the gear will do a better job in light airs on a small or moderate size boat and will remain functional down to about one knot of boat speed with the corresponding wind strength. However, a good sailor, balancing his boat properly, can make the vane gear steer even a very large yacht in surprisingly light conditions.
In these extremely low speeds, 1–2 knots of boat speed, the speed through the water might not be sufficient to move the servo-paddle to the side (which in turn moves the boat’s main rudder). In such conditions the servo-paddle will act as an auxiliary rudder! Located far aft, the servo-paddle should be able to steer the boat in such low speeds unless the boat is very large. Of course, proper sail trim is essential.
Your new MONITOR is shipped with a high performance, light airvane which will enhance performance in apparent wind speeds of 10 knots or less. It is 60% larger than your standard airvane. See 4.5.1The MONITOR will not work well in light air if the pendulum lines are too tight, since tight lines introduce too much friction in the blocks. With a tiller steered boat it is easy to adjust the tension by loosening the pendulum lines at the chain for the tiller fitting. With a wheel installation it is difficult to adjust the tension while sailing unless there is a "break" in the line as previously explained. (See 3.5.3.–"MONITOR Special" knot.) In light air you will get better performance with looser lines that run easier through the blocks.