Downwind Self-Steering Woes

[JPA Cate]

Ryban, we've done thousands of downwind miles with two headsails, the larger poled out to windward. Then sheet the main with two reefs in it very flat, and near amidships, it will damp the rolling. The reason for the two reefs in it is so that it won't slat much as the boat rolls. Our windvane was an auxiliary rudder type, and we had a light air fly for it and a normal to heavy, but it could itself be reefed down for heavier weather.

Ann

[robert sailor]

Originally Posted by 2big2small

Well we didn’t hand steer at all except the first day and the 6 h motoring through the dolldrums. That was my point. And we did it on a modern 2001 fin keel Beneteau. You could have saved yourself those “less than fond” memories!

Probably not the trip home from Hawaii is nothing compared to the trip there. We had winds primarily from the beam and often very gusty. Twice we had gales up to 35-40 knots for several days at a time so sheet to tiller were out of the question. The real good days were when we were hard on the wind and the boat would easily self steer in those conditions. I applaud your self steering feat and I'm not trying in anyway to make light of it, you obviously did a good job.

[seandepagnier]

Sheet to tiller works, but chafes sails most and has worst performance. Also requires adjusting often. It is a very useful backup system, and some types of rigs reportedly get much better performance without the disadvantages of chafe.

Wind vane works, but a light air paddle helps and a light weight oar also improves performance. In cross swell, it can have issues.

For best performance and least wear on sails, use electric autopilot steering to wind. This cost a small fraction of a mechanical wind vane, can be tuned on many more parameters more easily, and is easy to repair.

My autopilot uses only a few watts running in trade winds (0.2-0.5 ah per hour) , and it steers much straighter than the wind vane.

[Ryban]

I appreciate all the feedback.

I'm glad I've read about sheet-to-tiller steering, and understand the basics, just in case all my other methods of self-steering fail, but I'll keep my focus on getting the windvane operating better downwind.

My electronic autopilot is a tiller pilot (ST-2000, and ST-1000 as a back-up), and doesn't have wind input. I don't have wind input on the boat, anyway, other than the standard windex at the top of my mast.

I'll try adding a ribbon to the wind vane first, and lubricating all the moving parts. From there, I'll slowly start adding the surface area and see if I can get it to become more responsive without upsetting the balance too much.

My next downwind leg is about 800 miles, so I'll have lots of time to experiment. It also promises to be much more boisterous, so maybe these issues won't be present.

[PamlicoTraveler]

Originally Posted by gamayun

Chiming in here because I don't want to lose this thread and I have a new Monitor windvane that I haven't practiced on that much. I love the suggestions!!

Well, you made the right investment. A Monitor windvane works great downwind. In reality you have to go off ddw a little with anything, but a Monitor works great. I used it for a 2,000 + mile Canaries to Grenada run, and the only problem the Monitor had was with the sargasso weed. It is a blast to use the monitor in a healthy tailwind and watch and feel the boat sway its course based on the signals from the vane. I can sit there for hours and watch it react and steer the boat and think, dang, how is this working so beautifully and imagining how the frustration of long steering runs must have inspired the invention of the servo-pendulum systems.

I did try Wing and Wing occasionally, but if the seas has much roll, you are going to get frustrated with any vane, I think.

[charliehows]

I've come to the conclusion that windvane self-steering should be mainly designed for downwind sailing – most other points of sail are relatively easy to control due to the inherent balance between sails and hull. The way to measure downwind running is to look at the average at the end of the day – you'll find you've zig-zagged more or less in the overall direction you were intending to travel. It's worth fiddling with the setup of the steering unit because it can be fine tuned to reduce this to a minimum – but a certain amount of moving around is pretty normal.

[Cu Mor Glas]

Originally Posted by robert sailor

Mmmm the only time I've seen a wedge shaped wind vane was on a trim tabbed self steering system. I'll admit to being a bit dated on vanes but back in the day I owned several different ones and put thousands of miles on each one of them. Are you aware of any new wind vanes that use a wedge shaped vane that is hinged on the vertical..example Monitor, Airies,Cape Horn, Pacific Plus Windpilot or Hydrovane???

MR Vee uses an upside down horizontal wedge shaped vane. they even have a kit to fit their upside down vane to a navik.

upside vanes in general perform a better in light air downwind stuff but still weave around like you are describing.

an option that might make you happier is fitting a cheap tiller pilot to the windvane?

[double u]

the "V" of the "Mr VEE" is 90° to the winddirection & has no influence (if a "V" shape has any...I doubt it) on sensitivity.
rolling negatively influences coursestability as the vane accentuates any "roll-steer" the boat has (vane upright-boatwith gear rolls - vane "corrects" the apparent coursedeviation by steering to the wrong side)
very well explained here-http://www.windautopilot.de/_de/1_basics/windsensor.html in kraut though...

[double u]

here for the anglophones to the same topic:
http://www.windautopilot.de/docs/alkema/USD-vane.pdf

[Pauls]

A late reply to Robert - Regards wind vane foil section - I am not familiar with what current wind vane manufacturers are producing, but I am familiar with aerodynamics and the function of different foil shapes. A small angled triangle shape will produce larger correctional forces because the center of effort will be much further aft from the leading edge (ie pivot) than will a flat plate. Its simply a more efficient form as a wind vane. Also easier to adjust size for different wind conditions. If the sailcloth cover is laced on it is easy to unlace it and tie on a smaller cloth.

[robert sailor]

Hey Paul's,
I understand what your saying and if the vane was pivoting on a vertical axis then of course you are right and many of the older vanes that were used did in fact employ a triangle shaped wind vane. The new servo pendulum vanes operate on a horizontal axis and the vanes are often nothing more than a piece of 1/4" plywood with no foil shape. Others are flat thin pieces of plastic again with no foil shape, some are made of aluminum tubes and covered with nylon material and have some foil shape. It's really not needed as the vanes job is to simply stand up and that's done with a set of balancers that may need to be adjusted depending on the size and weight of the vane. It's quite normal to use a larger and lighter vane in light air and a stiffer/heavier vane in stronger winds although I know many folks who have used their light air vane in strong winds without any issues.Adjusting the vanes verticle angle is a very important part of insuring that it works properly. Assuming the vane is plumb to the boat, which will be it's most sensitive position and you are sailing downwind in a fresh breeze and you find the boat wondering excessively then tip the vane back and lock it in place and fool with this adjustment until you find the sweet spot. The more you move it back the less sensitive it becomes but don't overdo it as you can take away too much sensitivity, it's a bit of an art but anyone that have used these successfully will know what I mean. Remember these wind vane itself is not giving any real mechanical power to the vane they simply are meant to only move when the air pressure on one side of the vane is more than the other side. When the vane tips to the side it turns a gear or push rod that turns an oar in the water. When this oar turns in the water and causes the oar to swing to one side or the other in the water and pulling steering lines ...this is where the real power comes from and the faster you sail and the stronger the winds the more powerful these vanes are. There weakest time for them is in very light winds and very little apparent wind and moderate waves. It's these conditions that you have to play with them to get the best out of them. If you want to judge how the internal friction of one vane vs another is simply compare the size of the standard wind vane that they come with. Ive never seen a vane smaller than the Cape Horn system...It's very small compared with a monitor and that tells me that the push rod system is lower in friction than the more standard gears used on most of the others. My guess is that this vane would be very efficient in lighter winds. Most all of the vanes produced today do a decent job of steering, i personally love vanes when crossing oceans, they make so much sense, they use no power, they are mechanical, quiet and very reliable. When your sailing offshore your sails often shade the panels and autopiots are greedy with the amps. So you are running genset or engines on a regular basis. If you don't need an autopilot you remove a large load off your battery bank and save on burning fuel, heating up your boats interior and often saving the noise factor as large autopilot can be noisy. Vanes are like sailing, part art and part science. R

[Cpt Pat]

Twin jibs. Tillerpilot coupled to a masthead wind sensor.

Dead downwind, in moderate conditions, you don't even need poles. If one side heads up and luffs, the forces on the other jib swing the bow back to downwind, so it auto corrects. See vid. Here my 26 foot Ariel is surfing at 7 knots.

If you are sailing exactly downwind, you don't really need the autopilot (but corrections are snappier with one). If fact, with a full keel, or modified full keel, you don't even need a rudder. It's that stable.

This is difficult to accomplish with a roller furled headsail - which is why I don't have one.
My twin jibs are identical, with staggered hanks. A separate sheet is attached to each clew. Besides stability, the beauty of this arrangements is: if I need to reach upwind, I let the windward jib just lay against the leeward jib. And then, I just open them back up when I turn downwind.


"Your mileage may vary" with a fin keel. There's a reason there are diehard traditionalists still sailing the seas with "old" boats.

[double u]

"Ive never seen a vane smaller than the Cape Horn system"
it's even smaller than the Navik's?

[robert sailor]

Originally Posted by double u

"Ive never seen a vane smaller than the Cape Horn system"
it's even smaller than the Navik's?

Sometimes it's hard to use exactly the right words when describing something. The Navik vane is a small vane designed to be used only on small boats. I don't think they are made anymore and haven't been for many years. The part of the vane I was describing was the wind sensor or air paddle or wind vane whatever one wants to call it. I don't think the Navik has a wind sensor smaller than the Cape Horn but I could be wrong. The Cape Horn is also designed and built to steer much larger boats than the lighter built Navik. That aside I'm not promoting one vane over the other, I simply stated that the vane with the smallest wind sensor probably had the least internal friction and therefore might be more responsive in the lighter winds.

[double u]

didn't want to smartass you, rs, just to keep "the record straight" was very delicate & fragile looking, the Navik, popular with the frogs in it's time though & could stand up to bad weather too:
https://www.amazon.co.uk/My-Old-Man-.../dp/1565121023