Which Tiller Pilot for a Monitor Windvane?

[Zingaro]

On a Kelly Peterson 44 with a Monitor wind vane what kind of tiller pilot should I be looking for? Specifically I am looking at TPs and they are rated for the size of the boat. I believe, but maybe incorrectly, that I can choose the smallest since it only need to drive the Monitor and not the boat. Am I correct in this thinking? There is also a Raymarine C80 chart plotter display integrated with GPS on the boat. Is there any reason I want to spend the extra dough to link to the chartplotter?

Thanks

Danny

[mitiempo]

Email Scanmar for the best answer. They are the manufacturers of the Monitor.

[sailingdog]

Given the windvane, most of the tillerpilots should be able to handle the relatively low loads it requires. Having the tiller pilot linked to the GPS would allow you to sail a compass course using the tiller pilot if it was properly configured. This would allow it to act as a backup to the regular autopilot.

Originally Posted by Zingaro

On a Kelly Peterson 44 with a Monitor wind vane what kind of tiller pilot should I be looking for? Specifically I am looking at TPs and they are rated for the size of the boat. I believe, but maybe incorrectly, that I can choose the smallest since it only need to drive the Monitor and not the boat. Am I correct in this thinking? There is also a Raymarine C80 chart plotter display integrated with GPS on the boat. Is there any reason I want to spend the extra dough to link to the chartplotter?

Thanks

Danny

[lshick]

We have used a Simrad TP10 with good results.

Note that the design of the stub-vane contains some non-obvious requirements. In particular, the pin (onto which the cup of the TP10 rod fits) must be horizontal, and the cup must be rotated to match. If you have the pin and cup vertical, the tilting of the stub-vane will break something.

[Zingaro]

So my lack of experience will shine through here but. From what I have read here on the forum. 90% of sailors with a wind vane use it to steer the boat 95% of the time. I know being able to steer a compass course is an added luxury and not necessary but I guess I don't see the advantage to being able to steer a compass course the few times I am under power when I can't the majority of the time under sail?

[lshick]

There are two things going on here. You are correct that "90% of sailors with a wind vane use it to steer the boat 95% of the time." That assumes of course that the sailor in question has learned how to balance his sails, etc.

You do *not* want to use the Monitor when under power. Scanmar (the mfr) specifically recommends against having the servo-pendulum in the water when powering, because the prop wash will cause vibration and wear on the Monitor components.

Under sail, however, there are some points of sail (e.g., broad reach) where the apparent wind direction varies wildly and the Monitor (or other windvane) will have trouble holding a decent course. In these conditions, a stub-vane with a tillerpilot on the Monitor will do a better job than the windvane.

As a footnote, we use our little TP10 Tillerpilot as an autopilot for our Valiant 42 when powering in calms, by hooking the TP10 drive to a little bracket I made for our Edson wheel. It does a fine job in calms, steering us arrow-straight. You can see the hookup at our "projects" page (scroll down to the "Cockpit and Deck" section). If it starts getting overpowered, that just means that the wind has come up and we ought to start sailing.

Hope this helps.

[Zingaro]

Thanks I'll look it over. I don't clearly understand how a tillerpilot that isn't connected to the chartplotter holds any course?

My understanding is that the purpose of using a tiller pilot on a windvane is for when you have to motor. Scanmar seems to approve of the use of a tillerpilot on the Monitor. If the tillerpilot wasn't holding a compass course what is it holding? I don't need to spend $1k+ to lash my rudder.

[Paul_L]

Originally Posted by Zingaro

Thanks I'll look it over. I don't clearly understand how a tillerpilot that isn't connected to the chartplotter holds any course?

My understanding is that the purpose of using a tiller pilot on a windvane is for when you have to motor. Scanmar seems to approve of the use of a tillerpilot on the Monitor. If the tillerpilot wasn't holding a compass course what is it holding? I don't need to spend $1k+ to lash my rudder.

The Tillerpilot has its own internal compass. If it was connected to a Chartplotter then it could be directed to sail to waypoints. Something that is not worth doing.

Paul L

[lshick]

"My understanding is that the purpose of using a tiller pilot on a windvane is for when you have to motor." Wrong, wrong wrong! Please reread my earlier post. If you need a real autopilot, buy an autopilot. But as one of my professors used to say, "Don't use a steak knife as a screwdriver."

"Scanmar seems to approve of the use of a tillerpilot on the Monitor." Yes, but not when under power.

"I don't need to spend $1k+ to lash my rudder." True enough. On the other hand, you could spend $1K+ for a servo-pendulum windvane, and destroy it by using it as an autopilot under power. Your choice.

From Scanmar's site http://www.selfsteer.com/faqs/faq.php?ID=134: "This rig (tillerpilot to stub vane) is recommended for very light-air "ghosting" or limited slow-speed motoring only - high-speed motoring creates a lot of prop turbulence which may set up excessive vibration in the Monitor and its mounting system." Further down on the same page "We do not recommend this type of arrangement be used for extensive powering because the servo-paddle will be positioned in very turbulent water from the prop wash." You can read the rest of the paragraph there.

[Zingaro]

Thanks I over looked that. They give very conflicting info on their website.

http://www.selfsteer.com/products/monitor/autoPilot.php

When there is no wind and you are under power, or in extremely light air, the combination autopilot/windvane might be the best possible way to achieve perfect self-steering with minimum power consumption.

Hmmm What to believe? I suspect if questioned directly they will take the most conservative position. I tried steering with the windvane yesterday because I was concerned prop wash would interfere with the performance. I didn't notice that prop wash seemed increase the normal turbulence of the boat moving through the water. The boat is still doing 6-7 knots under power and sail which causes mild turbulence. I am inclined to believe that the depth & downward orientation of the prop on a sailboat directs the prop wash below the monitor oar paddle.

I still don't understand what course a tiller pilot is steering if not connected to the chartplotter or remote. Anyone clarify this for me?