Fitting Wind vane to Boat with Davits

[Richkayak]

Dilema.

I have just purchased a wind vane. (Windy), and going to fit it to my MG346 build by Northshore. The back of my boat the design is I am told called sugar scoop. The problem is I have just had a sail arch with integrated davets built and installed to hold the tender, which will sit just where I want to Wind vane to pretude. See attached pic of back of boat. The tender is heavy Ribeye with central consol and engine will stay attached so when on long passagges I will need to tightly secure the tender so it does not swing at all otherise this could fail. Any suggestions as to how I install the windvane and or hang the tender.?

[GILow]

Sorry to say it, but that thing looks seriously under-engineered.

Is it too late to return it and get something stronger? If so, there are some wind vane steering systems that have remotely installable wind vane heads that will solve your problem.

[model 10]

Also sorry to say, I don't think it will work. You can't have both the dinghy on davits and a windvane. Even if you could mount it so the vane would clear the dinghy, you will ruin it while hoisting the dink someday. Plus, windvanes need clean air to work, you can't have a dinghy motor in the way.

[GILow]

Originally Posted by Ecos

Also sorry to say, I don't think it will work. You can't have both the dinghy on davits and a windvane. Even if you could mount it so the vane would clear the dinghy, you will ruin it while hoisting the dink someday. Plus, windvanes need clean air to work, you can't have a dinghy motor in the way.

You CAN have a wind vane and davits, but you have to choose the correct make and model.

The OP needs to check out the Scanmar site for their offerings.

[ttex]

My friggin boat has davits and a monitor wind vane. Im losing my mind trying to decide what to get rid of.

[GILow]

To help the OP, here is one version of what you need.

https://www.scanmarinternational.com/auto-helm-hp

I am building my own, based almost entirely on the same principles. I have a much greater challenge than most boats (see picture) when it comes to finding clear air for a wind vane.

Early testing is working well, the rudder and trim tab work better than I'd dare hope, all that remains is for me to build the wind vane mechanism. Mine will be on an arm that swings out to the windward side of the boat to get the cleanest air flow I can find.

Looking at that Windy device, in the light of my own experiments, I can see that it has a number of engineering challenges that will be difficult to overcome. Aside from being built from VERY light materials (and have a read up on the recent Golden Globe Race if you want to learn what happens to lightly built wind vane gear), it also will create an extraordinary torque load on the mounting bracket that will tear off any boat in a bad cross sea. Yes, I know servo pendulums do not steer the boat directly, but boats fall sideways off waves so the mechanism has to handle those sorts of forces. Looking at that thing... no way.

[GILow]

Originally Posted by ttex

My friggin boat has davits and a monitor wind vane. Im losing my mind trying to decide what to get rid of.

That's a hard call... the monitor is excellent.

How about putting the dink on the deck for long passages? It's considered better practice anyway, then at least the monitor would be able to do its thing.

(Edit: in other words, keep both but only use the davits for short haul sailing.)

[Richkayak]

The Davits are solid. I had them made and they are integrated to the transom which is integrated to the sail arch, so that is solid.

I thought the wind vane that I am looking at is this:

https://windyselfsteering.com/selfst...-does-it-work/

[GILow]

For the OP, here's an old Autohelm on Ebay... going for a song... sort of.

https://www.ebay.com.au/itm/Yacht-Wi...M-/22262942569

[Jim Cate]

Originally Posted by Richkayak

The Davits are solid. I had them made and they are integrated to the transom which is integrated to the sail arch, so that is solid.

I thought the wind vane that I am looking at is this:

https://windyselfsteering.com/selfst...-does-it-work/

I have to agree with Gilow... that arch looks very inadequate to me for hanging a very heavy dink+motor on and going to sea. It is very tall and has no cross bracing whatsoever (that i can see). I don't think it is solid at all.

Doubtless it will suffice to hoist the dink when at anchor, but lurching about at sea is a different thing entirely, and large side loads will be imposed on the structure. I'd suggest having a competent engineer look at it before you risk going to sea with the dink up there.

And do consider what having ~500 lbs hanging perhaps 10 feet above the waterline will do to stability. Bad juju IMO.

Jim

[model 10]

[QUOTE=GILow;2976256]You CAN have a wind vane and davits, but you have to choose the correct make and model.

Did you look at the pictures of this boat? What side is the dink engine going on? What happens on a tack with the big ass center console dink in the way?

[AmericanVagrant]

I don't think we can deduce the adequacy of strength for this particular design based on photos alone. It certainly does not appear over-built, but it may very well be fine given the surface area of the rudder.

As to whether you can make that system work with davits is another question. They do require significant exposure to the wind.

[GILow]

Originally Posted by AmericanVagrant

I don't think we can deduce the adequacy of strength for this particular design based on photos alone. It certainly does not appear over-built, but it may very well be fine given the surface area of the rudder.

As to whether you can make that system work with davits is another question. They do require significant exposure to the wind.

From the photos it is simple to gauge the spread of the mounting bolts for the main pivot point.

It does not matter if the rest of the thing is built from titanium, the simple leverage principle applied to those mounts practically guarantees they will tear their way out of a fibreglass boat.

Maybe a steelie would hold them, but then the bolts would just shear off.

This stuff does not need an engineering degree to asses when it is that bad.

[GILow]

Originally Posted by Ecos

.



Did you look at the pictures of this boat? What side is the dink engine going on? What happens on a tack with the big ass center console dink in the way?

Yes, I looked very hard at the pictures of the boat, and even a few of the same model on various for-sale sites. Which is why I recommended the autohelm.

A). Auxiliary rudders (like the autohelm) do not need to be on the centre line of the boat. In fact, they can benefit by being slightly offset to keep them out of the turbulence of the main rudder.

B). A remote vane system like the autohelm frees you up to put the vane in a position to experience clean air flow, regardless of what you have strapped on the back of the boat.

Seriously, this one is not too hard. It just takes some lateral thinking.

One CF member just sent me photos just a few days ago of his autohelm vane which he has mounted ABOVE the davits. Perfect clear air flow up there.

[KadeyKrogen38]

It us not prudent to go to sea with a dingy hanging in davits.