Wind Vane steering for Multihulls do they work?

[neelie]

Does anyone have one installed?

What sort of boat and does it work?

I have read all the reasons why wind vanes wont work on Multis and I cannot recall ever seeing a multi hull with a wind vane attached. Yet the manufacturers web sites have pictures of vanes connected to Multi hulls - for example see the following link.

Self Steering - Hydrovane Selfsteer


Surely not Photoshop?

[imagine2frolic]

I have an emergency tiller on my boat. I have often wondered how I could make a windvane work. My dink sits between my sterns on a platform. For sure it could not stay there, but the platform would make a great start for a windvane.

[neelie]

Looking at the Hydrovane photos, the WV is mounted far off center, so presumably your dink on davits will still fit.

Conventional wisdom has it that WV's don't work well on Cats because of the large variations in apparent wind.

So how come Hydrovane show photos of a Catana 40 with WV attached? One would have go a long way to find a quicker, faster accelerating production catamaran.

Am I being naive to simply assume that just because it is physically possible to mount one on a Cat that the system will actually work?

Judging by the amount of crap which I have bought over the years which has completely failed to live up to the claims of its snake oil marketeers, I guess the answer can only be be yes.

Nevertheless, I live in hope that someone has developed a WV which will work on Cats.

[sandy daugherty]

Many cat cruisers use the autopilot extensively. I have no idea how successfully each brand can steer to wind.

[colemj]

I question the effectiveness of windvanes on catamarans. There is the large variations in apparent winds due to quicker acceleration that nellie mentions. But many cats don't accelerate faster than some monos that use windvanes. A bigger problem would be the windshadow from high topsides, cabintop, full bimini, etc that most catamarans have. If you look at the Catana 40 pictures, that vane could only work downwind or on a port tack at best. All other angles have a complete windshadow.

A couple of weeks ago I was aboard a 46' Warram that used the lower end of a Monitor vane controlled by a small tillerpilot in place of the vane. They said it worked perfectly and used little electricity. Also useful when motoring. Is there a reason that this isn't more widespread? I used to have a boat with a small Navico tillerpilot and it drew less than an amp when running.

Mark

[imagine2frolic]

My autopilot works a lot harder steering on the wind. As compared to steering on a heading.

[BigCat]

Originally Posted by colemj

I question the effectiveness of windvanes on catamarans. There is the large variations in apparent winds due to quicker acceleration that nellie mentions. But many cats don't accelerate faster than some monos that use windvanes. A bigger problem would be the windshadow from high topsides, cabintop, full bimini, etc that most catamarans have. If you look at the Catana 40 pictures, that vane could only work downwind or on a port tack at best. All other angles have a complete windshadow.

A couple of weeks ago I was aboard a 46' Warram that used the lower end of a Monitor vane controlled by a small tillerpilot in place of the vane. They said it worked perfectly and used little electricity. Also useful when motoring. Is there a reason that this isn't more widespread? I used to have a boat with a small Navico tillerpilot and it drew less than an amp when running.

Mark

To cope with the high freeboard and high windage of a catamaran, I'd look at a Cape Horn windvane. See: http://www.capehorn.com/ Winds at sea tend to be fairly steady usually, so I would think that a wind vane would work well offshore, at least in a slower cat like a Wharram, though I don't have any voyaging experience in multihulls.

[colemj]

It's not the forces imposed by high freeboard, cabintop and biminis on cats that is the problem. The problem is that these things block the wind from reaching the vane altogether when the wind is forward of the beam.

Mark

[BigCat]

Originally Posted by colemj

It's not the forces imposed by high freeboard, cabintop and biminis on cats that is the problem. The problem is that these things block the wind from reaching the vane altogether when the wind is forward of the beam.

Mark

Yes, I know. The Cape Horn is customizable, and you can get the vertical post that the vane mounts on as long as you want, so you can put it as high as necessary. I sailed 10,000 miles with an Aires, and loved it.

[neelie]

More than a few Cats have hydraulic steering. I'm not so sure the servo oar type wind vanes (Monitor, Cape Horn, etc) will work so well with hydraulic steering. To their credit, nowhere does Cape Horn overtly advertise that it will work on a Multi (I see 2 Wharrams on their list of fitted boats).

Judging by the lack of any multi owners responding to say that they have a WV installed, I guess my question has been answered; they obviously don't work..

[imagine2frolic]

I always thought that in the trades with the wind on the quarter, or there about. That a windvane would work fine. Also I would think if you have a tiller, and the hydraulic autopilot is off. That everything would work fine. I have never used my emergency tiller, but I think in the near future I will have to just put it on, and play with it.

[neelie]

I2F : Ah ha!.. I see your point and where you're going!. Now, why didn't I think of that? Does your E-tiller work on both rudders or just the one to which its attached? Is there a chance your rudders may need re-aligning after using the E-tiller? I am curious as to the outcome of this experiment - please PM me the results.

As far as wind shadows go, it may be possible to extend the height of the air vane to a point where its in in free air - so maybe the Hydrovane might work. I have written to them and am awaiting a response.

[Wotname]

FWIW, the book "Wind-Vane Self Steering" by Bill Belcher does cover a lot of the issues of wind vane steering for high speed sailing including multihull aspects.
IMHO, this book should be considered a bible of wind vane steering.

[imagine2frolic]

The e-tiller is attatched to only one rudder, but then again there is a drag link running through the stern beam to the other rudder. I was thinking of fabricating a second attatchment so I would have 2 tillers. Then it would be like a hobie, and in the middle a windvane attatched?

[BigCat]

I would be inclined to ship a removable (like a kick up) rudder on the aft end of the bridge deck for a windvane to operate, if it were the kind that operated through the boat's rudder.