I agree with Scott that mainsail adjustment (trim and reefing) is the way to manage weather helm. Zygote doesn’t have a cunningham, so I use additional halyard tension to put the draft of the main around 40-50%.
When sailing to weather, I tend to sit on the windward side. So I usually cross over to leeward to look up the main and judge where the max draft is. A reference mark halfway along the boom makes it easy - I aim to keep the max draft forward of the imaginary line running from that mark parallel to the main leech.
I respect Roger’s judgment and expertise, but I sure wouldn’t want to handle the engineering problem of moving the mast aft just to manage weather helm.
Sumio, whose judgment and expertise I respect, considered the weather helm problem and calculated that a bit of sail recutting, cutting more roach into the leech of the main, would be an easy way to make the weather helm more manageable. Sumio had quoted to me exact measurements to recut a standard Elliot Pattison mainsail - from memory, the leech only had to be curved in by one inch or so.
On Zygote, I long ago marked the sole of the cockpit such that I know when the tiller is at 3 degrees, 6 degrees and 9 degrees off the centreline. I consider weather helm of 3 - 4 degrees of tiller to be acceptable. When I need more than 3 degrees of tiller, I think about putting in a reef in the main while leaving the jib full (close-hauled, I be using a jib, close reach and further off the wind I’d use a jib plus staysail) or, more simply, easing the mainsheet or (in light air) working the boom to leeward (Z doesn’t have a traveller, so I work the mainsheet through the blocks, but that can only be done in light airs!).
Sailing to weather, much of the drive comes from the foresails. Reefing the main balances the pressure from the foresail(s), without appreciably reducing the drive.
The weather helm that is associated with more than 3 degrees of tiller correlates with a heel angle of more than 10 degrees. So I’m now putting in a reef when the heel angle is consistently more than 10 degrees (when I started sailing Z, I would only consider a reef at a heel angle consistently more than 20 degrees).
I’m sailing Z flatter than before. And I don’t think I’m losing significant boat speed. But it’s impossible to judge without sailing alongside a similarly laden BCC28.
I understand Douglas’s argument about floatation from his Foss foam rudder, but I don’t know enough to comment.
In sum, cutting or re-cutting the mainsail is one way to go (and easier than relocating the mast). A means of measuring your tiller angle gives you an objective way of measuring weather helm. And then mainsail trim and reefing are easy ways to manage weather helm.
Cheers
Bil
