Yaw damping on windvanes

[KellysEye]

>Groundhog Day?
You already took issue with that very quote from Daydream Believer...last September. He replied, argueing his position...also last September. If you're going to keep doing this periodically, it might be a kindness to tell him so he can arrange is social life to suit

Daydream Believer is wrong in believing you don't have to balance the sails and have a neutral helm to get the windvane to steer straight, so I point that out. There is a danger people here will believe him, some already do and my bet is they have never had a windvane, so I will continue to point out he is wrong if he posts it again. Perhaps to arrange his social life he can PM that he is about to post something wrong so I can be ready and waiting.

 

[Daydream believer]

>Groundhog Day?
You already took issue with that very quote from Daydream Believer...last September. He replied, argueing his position...also last September. If you're going to keep doing this periodically, it might be a kindness to tell him so he can arrange is social life to suit

Daydream Believer is wrong in believing you don't have to balance the sails and have a neutral helm to get the windvane to steer straight, so I point that out. There is a danger people here will believe him, some already do and my bet is they have never had a windvane, so I will continue to point out he is wrong if he posts it again. Perhaps to arrange his social life he can PM that he is about to post something wrong so I can be ready and waiting.

I did not ask to get into this spat. I stated the situation as I find it. In the context of my boat I am NOT wrong. It is also an opinion suggested to me by the current manufacturer when i was discussing buying a part for the oar. I am sure that he has far more experience of the Aeries than you will even if you live to be 200.
But at the end of the day it is to each his own. If you have the perfect boat that is so well balanced downwind then you are very lucky. If you have found what you consider the optimum way of setting the vane up then fair doos to you. But please do not suggest that the way I have my rig set up is wrong or that it does not work for me because it does.
Some will agree with you. some will not. That is what makes life interesting. I suggest we just let others decide what suits them.

 

[fishermantwo]

While it's easier to set the boat to sail with the sails trimmed with a windvane it's not necessarily true they will not steer straight out of balance. When I reef the main I obviously ease the main off first then lower some main. Or when I furl the headsail and hoist a cruising chute the boat initially changes course a bit then sails straight again. There is hardly anytime the helm is neutral. When setting the windvane we set the weatherhelm when we steer the desired course as we engage. Altering the sails as we sail upsets the amount of weatherhelm we have preset and the boat will alter course. If your reefing upwind the boat will fall away a few degrees while the main is having no effect, but will come back on course when the new reefed main is sheeted in and your preset weatherhelm takes over. Sailing dead downwind you may have neutral helm if you have a poled out headsail etc. The majority of the time you will have weatherhelm, especially reaching.

 

[mattonthesea]

My Monitor is a very powerful windvane but the makers still advise that proper sail balance is essencial.I've learnt that reducing the mainsail often helps a lot with directional stability.The Fulmar is very well balanced but the Monitor can be fussy especially in the conditions the OP described.

I found the same with my Aires on a Rival 32. I had previously checked (warning: geek alert!) checked the speed against the heel angle and noticed that over 23 degrees she slowed down. So reefing the main early helped keep the balance and reduced yaw on the windvane.

I also found that playing with the chain notch on the tiller would help with any left over downwind yaw.

I get the feeling that this discussion is around some very individual characteristics. Apart from already mentioned, do the rudder shape, the tiller/wheel set up for the steering lines, the proximity of clew to the vane etc have effects too?

 

[KAM]

I sail with a monitor and fin keel. I find that the monitor is not too fussy about sail trim and copes well in most situations. Sailing downwind I had assumed that the large vane would work best due to the lower aparrent windspeed but find that boat rolling tends to have a large influence on the vane pendulum angle resulting in an oscillating course. Changing to a smaller vane results in a much straighter course. Its not really damping but the vane assembly is much less sensitive to the boat rolling. A bungee on the balance weight has a similar effect but not as elegant.

 

[KellysEye]

>@Kellys-Eye - Do you trim the sails differently when handsteering vs. windvane and if so how? And what type of boat (hullform/size are we talking about?)

We didn't do anything different when hand steering lee and weather helm are a pain so we balanced the sails. Our boat was a long keel with a cutaway forefoot heavy displacement steel ketch. When I helped deliver Kelly's Eye from Lymington to Scarborough with the new owner we decided to see if could not use the wind vane balance the sails and lock the steering. The wind was 20 to 25 knots and we got very lucky with a wind change so we reached all the way and got there in three days the fastest passage I've ever made in that number of days. We did have to hand steer twice for course changes and going into the marina.

 

[rob2]

This whole issue of sail balance seems to be being argued on different grounds from each side - and with no explanation of the cause and effects involved. The OP's question was about the use of a servo pendulum windvane when going deep downwind. Sail balance does affect the performance of any steering system and we all know that a bermudan sloop doing down wind under white sails suffers an imbalance due to the different areas of sail either side of the centreline. Reefing the mainsail can greatly alleviate this problem and also reduces heeling effects, but if you don't reef then whether hand steering or under windvane steering will be more sluggish to one side. A servo pendulum generates a lot of power and will cope but won't steer a very straight course.

A Hydrovane is far less powerful as it is an auxiliary rudder system and does not have the servo blade to generate hydraulic force. It is essential with such a system to achieve best sail balance to minimise the required steering force, although some owners do lock the main rudder with an offset to cope with the weather helm, leaving the windvane rudder to cope only with adjustments to course.

Rob.

 

[KellysEye]

>Sail balance does affect the performance of any steering system and we all know that a bermudan sloop doing down wind under white sails suffers an imbalance due to the different areas of sail either side of the centreline. A Hydrovane is far less powerful as it is an auxiliary rudder system and does not have the servo blade to generate hydraulic force.

That's why we had a Twistle rig with two equal sized sails. A Hydrovane has 3 adjustable power settings and steered our 15 ton steel boat with no problems, it certainly didn't lack power.

 

[rob2]

Exactly - the sail plan has to be matched to the steering system in use. The Hydrovane doesn't lack power to turn its small auxiliary rudder, though it could never be used to turn the main rudder which can be set off centre to eliminate some lee or weather helm. The difference with a servo pendulum system is that the windvane only turns the servo blade but in so doing the servo blade generates a substantial hydrodynamic force, more than sufficient to turn the main rudder. With all that power, sail balance is not so critical BUT can affect the straightness of the course steered.

Rob.

 

[Pagetslady]

Surely we all strive to get our sailing boats to sail a balanced as possible to get the most comfortable and speedy sail possible, it is never comfortable sailing with loads of weather or lee helm a well balanced boat be it helm or hull will always give more satisfaction and pleasure, however it is being steered. It seems pointless making a steering system work harder than need be.
Mike