Control of Weather Helm

[hpeer]

Originally Posted by StuM

Centre boom sheeting puts big loads on booms. Sheeting the boom only 1/3 of its length from the mast would not be a good idea at all. Definitely not recommended unless the whole thing was originally designed for it.

570/823 is not too bad an angle for a vang (about 35°). What's the vang purchase ratio? Sounds like yours may be a bit light. 8:1 is not uncommon.

Take a look at the 8:1 Cascaded Fiddle on the Harken website:
Harken



or this one at
8:1 and 20:1 Cascaded Boom Vang


One option if your purchase is too low is to set it initially with the boom sheeted hard on and centered.

And if the boom end is still inboard when you want to tighten while underway, just pulling down on the end can help get a bit more load on the vang.

I found this helpful. We have a larger heavier boat and the vang purchase is only 4:1. Also no traveller. The only complication is I have a Dutchman boom break. But I think I have enough room to do this.

[UNCIVILIZED]

Originally Posted by hpeer

I found this helpful. We have a larger heavier boat and the vang purchase is only 4:1. Also no traveller. The only complication is I have a Dutchman boom break. But I think I have enough room to do this.

I'm not sure why space for both is tight on your boom? That said, it's easy enough to attach both to the boom using a seperate spectra strop for each. Just ensure that the boom is strong enough to take the loads imposed by said hardware when mounted there. You might even consider going to multiple attachment points leading to a D-ring for the hardware, or some other option.

For the OP. A traveler needn't be fancy, nor purchased from a marine hardware maker or chandlery. You can fabricate simple ones using metal bar stock or tubing & a sliding ring.
Think about how a ring slides along a shower curtain rod. You can attach the mainsheet tackle to the sliding ring, & put control lines at both ends of the rod to control the sheet's position. And just anchor the ends of the rod to the deck. Or have the tubing bent 90 deg. at each end, & a mount akin to that at the base of a stanchion welded on.

There are lots of ideas of how to DIY boat hardware in the book Steel Away https://www.amazon.com/Steel-Away-Gu...rds=steel+away

[subie]

Originally Posted by Steady Hand

Jack,

I think photos to show a particular boat's current setup are good to help others see the possibilities and possible limitations.

My Suggestion: Post a few photos showing your boat's current boom/cockpit arrangement, and indicate where you see problems. I would post photos from the mast facing aft, and from the stern or helm facing forward. Show the cabin top in a photo and the cockpit too.

A quick google search found this image of a Morgan 31 in SA and shows the use of a traveler in the cockpit. Your boat's setup may be different.

Hope that helps.

That is not a pic of the morgan 31 but of a flamenca 25 named Quest when the owner of the blog still had her.

[Moontide]

Hate 5o say people are wrong but easing the main deports the main. An exception is if the main is overtrimed and you are sailing deep enough then trimming more will depower. If wind is forward of the beam the timing more will increase load.

Easing the sheet eases the leach and will depower. The OP didn't say if close, beam or broad reaching which calls for different depose ring techniques. That being said, reefing usually makes it easier to control weather helm

[Moontide]

Sorry, didn't proof but I think you all can figure out the wrong words. Hate autocorrect. 😊

[Kim Klaka]

Originally Posted by jrbogie

you make the same mistake in thinking that i've seen many make. you don't depower a sail by easing the sheet. you depower by INCREASING sheet tension. when you ease the sheet you induce more curvature in the sail, especially up front. you're powering up the sail. by increasing tension you flatten the sail and move the deepest draft aft thereby DEPOWERING the sail. a traveler is what you need. with it you can induce twist into the sail keeping the lower portion full and powerful and reducing power at the top of the sail where forces are acting to increase heel and therefore the weather helm you want to reduce. you would do this by hauling the traveler to windward, i know, counterintuitive but stay with me, and easing the main sheet. in a blow this moves the boom to the centerline of the boat for maximum pointing, powers up the lower portion of the main and spilling air out of the upper portion. much the same effect as tucking in a reef only easier.

I don't think the above explanation applies to this rig. Increasing mainsheet tension does two things:
a) pulls the boom closer to the centreline of the boat and
b) tightens the leech
Both these effects result in an increased angle of attack, but no change in camber. The camber in the lower part of the sail is determined by the distance from the tack to the clew, which is fixed unless you adjust the outhaul. The only way I can envisage mainsheet tension flattening the sail is if it induces mast bend (i.e. takes over from the backstay tensioner), which will flatten the mid-height part of the sail. However, it is extremely unusual to see that effect on a typical cruising boat rig. Generally it only happens on a bendy fractional rig mast, and needs heaps of sheet tension.

[boden36]

If you still have weather helm after flattening the main, and assuming the main is correct and has not stretched to a belly, then you may need to consider lessening mast rake. Alternatively, a larger foresail if she will carry it or reduce the size of the main slightly.

Regards,
Richard