I would like to add my comments to the excellent article Terry Sargent wrote regarding automation of a windvane (“Automating a windvane,” Sept./Oct. 2000, Issue No. 108).
We made the same modifications on LaVida our Cape Dory 33, using the Raytheon ST1000 atop our Monitor windvane. Our decision to use this method was based on the cost savings afforded by the elimination of a wheel-based autopilot and not wanting to drill, cut, and add more electronics to the boat. Plus, this approach would eliminate the increased amperage draw from a wheel-mounted autopilot.
We had previously installed a fixed three-blade Michigan Wheel prop. We used the three-blade prop for the increased thrust and control astern it afforded.
We put the system to the test during our round trip from Lake Ontario to Georgetown, Bahamas, and back. Our system was set up almost exactly as Mr. Sargent’s and, though it initially worked well, we encountered a consistent vibration in the Monitor windvane, from the prop wash while under power.
I contacted Monitor and inquired about the vibration, and they responded by saying that, although they are aware of the conversions, they didn’t recommend them because the vibrations from the prop wash hitting the paddle will wear various parts out much more quickly than normal usage. They were very helpful in their suggestions, even providing pictures of existing systems.
After having invested some considerable time seeking a solution, in the end I reverted to purchasing a new Raytheon ST4000 wheel autopilot with the ST600R remote control (a valuable addition when one wants to seek shelter under the dodger). Now we have the best of both worlds and have eliminated the vibration issue on the windvane. After more than 8,000 nm the dual system has proven its worth and reliability.
In summary, it may be that our hull configuration coupled with the windvane that produced excessive vibration, I don’t know, but others I have spoken too with the same installation have expressed similar problems. I wanted to error on the conservative side and not harm the “Windy” the windvane, she’s far to important to put in jeopardy.
In closing, I’d also like to take a moment to commend Scanmar for their excellence in product support and in the reliability of their Monitor windvane. I’ve had the unit on board for almost two years now and it has proven its worth in one hellish storm after another and brought us safely through.