The two types of vanes are horses of different colors. An auxillary rudder system gives you a backup for the main rudder should it fail and doesn't have to deal with attachment to a wheel
or rudder. I did a solo TransPac this past summer with a WindPilot Pacific Plus auxillary rudder vane. WINDPILOT - Products: Pacific Plus
It steered the boat without a problem in force 3-4 following wind and sea conditions running wing and wing for almost all the way. I made up a larger lightweight corrugated plastic (8"x4') wind vane
that handled the relatively light relative wind of 5-8 knots often surfing without a problem. In very light air conditions, while ghosting, the vane will also steer well. The standard plywood
vane works in winds over 5K. This auxillary rudder system will steer the boat with virtually no forward way on. The wind sensing vane is it's only limiting factor and I pretty much solved
that with the plastic wind vane for extreme ghosting situations or downwind sailing. The vane was extremely easy to mount. I did it in an afternoon, by myself, in a rainstorm. The mounts were designed for a reverse transom. I just switched them top for bottom on my flush transom boat. In short, I couldn't ask for better performance. Haven't had the pleasure of using it in very high wind running conditions but certainly has worked well in all other conditions. The auxillary rudder system may also work better if you use a tiller pilot to set heading under power. Believe Monitor, for one, doesn't reccomend using a tiller pilot to set the heading for their vane because of prop wash.
The disadvantages of the system are cost. I bought mine used off a much larger boat for two US boat units. New, they are 7 US boat units. For my boat which is extremely rudder challenged wthout the vane, it's made manuevering in tight quarters an adventure. Pretty much have to back and fill with the engine
to make tight turns to stbd. Turns to port are an adventure in narrow marina fairways. As I said my boat is very rudder challenged at the best of times so expect the vane wouldn't be such of a problem on a fin keel
, separate rudder boat. The guy I bought the vane from who had it mounted on a 43' fin keeler was surprized I was having problems maneuvering with the vane. The vane is also not an instant disconnect from steering
. Must go to the stern and disengage the vane to steering rudder gear
to disengage the vane. Since I mostly single
hand that has been an issue which wouldn't be a problem with one or more crewmembers aboard. One ownner I talked with with a Hydrovane on a Westsail 42 thought the vane wasn't sensitive enough in light air sailing. Didn't really discuss it in detail so not sure exactly what his issues were and that was one of their very early vanes.
My boat originally had a Monitor on it. It didn't work well at all because of an interface problem with the Wheel
and the unbalanced barn door rudder. The vane just wouldn't steer the boat below 4knots of boat speed/10k plus relative wind. It was probably not the fault of the Monitor but the Boat's wheel system requiring too much force to turn the wheel at low speeds and the difficulty of getting the controls to the forward mounted wheel. Over 4k the vane worked mahvellously. I was in the process of trying to figure out how better to run the control lines and solve the boat's steering inertia when the WP Pacific Plus came along. What it taught me was pendulum servo vanes are practically guaranteed to work with a tiller but may have problems with a wheel on some boats. Had an Aries on my Westsail 32 and it would steer the boat if the boat would sail. I was totally happy with it and still think they are the best vane out there. Love the ease of changing heading with the click system. The continuously adjustable heading system on both the WP Pacific Plus and the Monitor were a PITA. The pulley system on the Monitor tended to derail unless the pull of the line was directly inline with the pulley and the WPPPlus steering line slips and is not intuitive which line to pull to change heading. Other boats with wheels have worked well with Pendulum Servo systems, even fifty plus footers, so suggest you check and see what other people's experinces have been with similar boats. The PS systems also have less drag. You've got the boats rudder, only, doing the steering. You aren't dragging around that big auxillary rudder all the time, just the much smaller pendulum rudder. YOu can also kick the PS rudder up out of the water
so there is no effect on powering or sailing without the PS engaged.
So the intricacies of mounting the control lines, possible problems with wheel steering systems and the fact it steers through the boats rudder are the negatives of the Pendulum Servo. The rudder issue may not be that big a deal as both Monitor and SailoMat
rudder options for their vanes. Actually, when I say PS systems steer through the boats rudder is a negative, I'm not being fair. When I had a PS system, that never entered my mind.