Multihulls: Windvanes vs. Autopilots

[UNCIVILIZED]

Originally Posted by sailing_gal

In the past 2 years I have been on 5 different sailboats that lost their autohelm due to one reason or another-- something broke. So, on my monohull I carry both my autopilot, and a spare motor for it, and I have a Hydrovane. I can see how a Hydrovane may not work well on a Cat. But I like redundancy. I do know of people who have 2 AH's installed on their boats- so when (not if) one breaks, they have a back-up.

Yes, AP's are great assuming backups, spare parts, & a reliable supply chain, but... failures are quite common. Which to some degree is the basis of my questions.
It's not uncommon for singlehanders to have crates full of spares when doing long races. And to spend a fair amount of time rebuilding their AP's so that they can stay in the race. As opposed to vane's, which are much, much simpler. Though they perform to a lower standard, assuming they work with the boat type.

[daletournier]

Originally Posted by robert sailor

Where do you get the idea a windvane is "specifically " designed for the rolling a mono hull does?
A vane is simply designed to steer to the apparent wind and as others have said Cats often have so much junk hanging around the stern that it is harder to get clean air. I agree with that but the same can be said for many monos. When the wind is from about 150 degrees and aft it's not as much of a problem but even then it may not be clean air if a bunch of junk is right behind the vane.
I'd say this, on your typical condocat which most cruisers own IF you could get clean air a vane could easily steer it, same for 99% of the cruising mono hulls. Doesn't work with hydraulic steering though. Needs to be mechanical.
In strong winds vanes can normally out steer most autopilots although the latest models of pilots are excellent.
If a boat is sliding down the backside of a large wave the vane automatically corrects and gives full helm in the correct direction thus averting a broach.
There are two basic types of vanes, servo pendulum and vanes using their own rudders..
Servo Pendulum vanes operate on the principal of using an oar in the water to transfer power to the steering system. If you were in a canoe and put an oar in the water held straight with the flow of water it would remain straight but if you rotated it, even a little it would quickly pull the oar to one side or the other depending on which way you rotated it. The servo pendulum uses the windvane to drive a mechanical system, some times gears or bent pushrods to convert the back and forth movement into rotating the oar in the water. So if you move the wind vane one way it turns the oar. These are very powerful vanes and very quick to make corrections. The power comes from the oar in the water which is attached to steering lines that go to the wheel or tiller so the faster the boat speed the quicker and more powerful the response.
The second type of vane uses the windvane to turn an auxiliary rudder. Obviously you need a very large vane to drive an auxiliary rudder. Hydrovane is the best known of this type and it uses a built in transmission to increase the force of the vane to turn a balanced spade rudder. There are advantages and disadvantages to both systems but there is no doubt that the servo pendulum vanes are the most powerful. All vanes need to drive a boat that is balanced and not overpowered as vanes are not in love with unbalanced helms although as long as you've got the boat speed the SP type is better able to deal with it. I could not imagine a Cat being steered by an auxiliary rudder so in my mind it would need a servo pendulum.

If your planning on voyaging and crossing oceans semi regularly, you own a typical cruising mono hull that is under 50 feet then a vane is a wise choice as it is mechanical, uses zero electricity and usually very dependable and dead quiet.
If your coastal cruising or cruising the Caribbean, the Med or Mexico, save your money and just buy a good autopilot.
Personally I can't see a market for a vane on a condocat, these boats typically are used for local sailing and even if they are used in crossing oceans the owners are well enough heeled to own 2 autopilot systems that are top of the line plus they all have massive use of electricity so the little extra a modern pilot uses wouldn't even put a dent in there ability to make power. The other owners of Cats that prefer higher performance can't use a vane as these boats accelerate at rates that a vane can't really cope with.

In regards to large vane ,Hydrovane have recently modified their vane so it extends alot higher, you can adjust up approx another foot to the vane height, it can be standard or bigger.
Ive just added it but haven't tried it yet.

I also agree that often the vane reacts quicker than the autopilot.

Sent from my vivo Y35 using Cruisers Sailing Forum mobile app

[boatman61]

Maybe you should contact Rory Mcdougal, he's been using a wind vane steering system successfully for years on Cooking Fat.. mounts it on the Stbd hull and it operates his tiller bar.

[robert sailor]

Originally Posted by daletournier

In regards to large vane ,Hydrovane have recently modified their vane so it extends alot higher, you can adjust up approx another foot to the vane height, it can be standard or bigger.
Ive just added it but haven't tried it yet.

I also agree that often the vane reacts quicker than the autopilot.

Sent from my vivo Y35 using Cruisers Sailing Forum mobile app

Hydrovane is owned by a Vancouver couple that I know quite well. They added more surface to both the vane as well as the rudder as the older ones had limitations in certain conditions. I've crossed the pacific and returned using a Hydrovane so I know the unit quite well. I've also owned 4 different servo pendulum vanes. I personally really like windvanes if for no other reason than the use of electricity and deep down I don't trust autopilots as I've had more than my share of break downs. My first sail to Hawaii was under autopilot and I had two of them but they were light duty and on the return leg I managed to ruin both of them, hand steered for close to 3 weeks with my wife and Son and never plan to do that again...well our crossing from the Med to the Caribbean was autopilot only as our current boat doesn't have a vane, fortunately pilots are getting more reliable than they were 35 years ago but deep down I still prefer vanes when crossing oceans. Hope you enjoy yours, if you ever need any tips give me a shout. R

[mawtty]

Just a note on Robert Taylors reply:
Wind vanes are sensitive to changes in monohull trim.
1. The flipflap is weighted and so has sensitivity to gravitational pull so when the boat heels the vane adjusts the helm to suit.
2. The pendulum oar can be set in a way that counters broaching before the flipflap picks up the change of wind, thus countering the broach before it gets too much. You get this well thought out on the Flemming but sadly not on the Airies design.
Tulku Tim.

[donradcliffe]

A wind vane is not going to work on a boat which can sail faster than the wind. When you are reaching on these boats, as you bear off the apparent wind will come forward, and as you head up the apparent wind will come forward. Sounds crazy, but its true.

[robert sailor]

Originally Posted by donradcliffe

A wind vane is not going to work on a boat which can sail faster than the wind. When you are reaching on these boats, as you bear off the apparent wind will come forward, and as you head up the apparent wind will come forward. Sounds crazy, but its true.

Good news and bad news....the bad news is your absolutely correct. The good news...it's unlikely there is maybe less than a handful of cruising mono hulls or multihulls owned by
members on this board

[robert sailor]

That fall into that category. ..

[Paul L]

Originally Posted by robert sailor

Good news and bad news....the bad news is your absolutely correct. The good news...it's unlikely there is maybe less than a handful of cruising mono hulls or multihulls owned by
members on this board

It doesn't have to be that high a performance boat to cause problems with a windvane. Downwind any boat that will surf causes issues. The apparent wind goes forward as the boat speed goes way up for a brief bit. Then the WV turns the boat to compensate just when you want the boat to drive in a straight line down the wave.

[robert sailor]

Originally Posted by Paul L

It doesn't have to be that high a performance boat to cause problems with a windvane. Downwind any boat that will surf causes issues. The apparent wind goes forward as the boat speed goes way up for a brief bit. Then the WV turns the boat to compensate just when you want the boat to drive in a straight line down the wave.

Mmmm yes I guess on a real quick boat that could be an issue but my last boat with a vane was a Tartan 44 and it certainly would surf on waves when the winds were higher but it was never really an issue. I might get 10 or 12 knots boat speed but only very briefly. If the surfing last a much longer time like sailing a Santa Cruz 50 under spinaker then that would be very different, fortunately those boats are driven by hand as under those conditions most skippers don't trust the autopilots although these days the pilots are probably good enough. But cruisers are unlikely to be sailing under spinaker in 20-30 knots of wind. Multihulls that most of this gang are sailing are in a similar speed range as cruising monos so probably not an issue with them either.

[Paul L]

Originally Posted by robert sailor

Mmmm yes I guess on a real quick boat that could be an issue but my last boat with a vane was a Tartan 44 and it certainly would surf on waves when the winds were higher but it was never really an issue. I might get 10 or 12 knots boat speed but only very briefly. If the surfing last a much longer time like sailing a Santa Cruz 50 under spinaker then that would be very different, fortunately those boats are driven by hand as under those conditions most skippers don't trust the autopilots although these days the pilots are probably good enough. But cruisers are unlikely to be sailing under spinaker in 20-30 knots of wind. Multihulls that most of this gang are sailing are in a similar speed range as cruising monos so probably not an issue with them either.

Maybe it was my lack of expertise with the windvane I had, but I could not trust the vane downwind with typical tradewind winds and large swells. No problem with the AP. Going from 8kts to 12+ was typical( usually with small white sails). Add 2 to 4 kts for maxs.

[boatman61]

Originally Posted by boatman61

Maybe you should contact Rory Mcdougal, he's been using a wind vane steering system successfully for years on Cooking Fat.. mounts it on the Stbd hull and it operates his tiller bar.

https://www.youtube.com/watch?v=Guy0QCxJLAU

https://www.youtube.com/watch?v=6rrtbiAk2JA

[robert sailor]

Originally Posted by Paul L

Maybe it was my lack of expertise with the windvane I had, but I could not trust the vane downwind with typical tradewind winds and large swells. No problem with the AP. Going from 8kts to 12+ was typical( usually with small white sails). Add 2 to 4 kts for maxs.

Well I can't say, don't know. Sailing about 150 miles off WA Or coast in 30-35 knots downwind for a couple of days straight the vane we had at the time (Fleming ) easily handled our boat in large seas. In the stronger winds I'd tilt the vane back and it would stabilize and desensitize the action on it.

[daletournier]

I had the hydrovane on my last boat. It was great downwind regardless of wind strength, I trusted it more than my raymarine.

Sent from my vivo Y35 using Cruisers Sailing Forum mobile app

[donradcliffe]

Originally Posted by UNCIVILIZED

[COLOR=black]

Bottom line: In your experience, what works & doesn't, when, & why; on 40'+ fast mono's, & mid-speed multihulls, such as something like a 37' Searunner (or faster), a Santa Cruz 40', Holby, Olson, or even a Class 40.

I agree that most cruising boats don't have that speed potential. Recently I've been driving Merlin during sail testing with its new keel. The apparent wind effect I described is pretty profound on that boat. Its much stronger on a big sled than on a Santa Cruz 40 or 50, but even those boats have it in lighter winds.

The picture is the old Merlin configuration--the new configuration has twice the righting moment, more sail area and uses asymmetrical spinnakers.