Will a boat trimmed by the head have increased weather helm?

[nuvaslacker]

Maurice Griffiths, a noted boat designer and writer (UK), wrote about one of his traditional boat purchases which had overwhelming weather helm. His solution was to move most of the internal ballast aft which resulted in a sweet handling boat. Weather helm was something that many traditional working boat based designs did suffer from and he discussed the problem in one of his books; unfortunately I can't remember which book it is. They're all worth reading, about cruising the East Coast of the UK in old wooden boats in the 1930/40s, with observations about cruising boat design.

[danstanford]

Originally Posted by rkarakai21

I don't sail in sustained 15 knots with the full 150 genoa, I roll it up to working jib size, as i've found the full genoa seems to exacerbate weather helm once you reach a certain windspeed. When I said 10-15 knots windspeed I meant 10 knots sustained with gusts reaching 15.

In terms of mast bend, I currently have the mast tuned with a slight aft bend. I don't have an adjustable backstay or a very bendy mast, she's quite stout, so I can get a little bit of tuneabililty there but not a ton, and not really something we can quickly tweak as were sailing.

Might have to borrow some 50 lb lead ingots and start getting creative shifting weights around.

Someone mentioned center of effort up thread and that is what I think of when I read about weather (or lee) helm. If the boat is designed to sail with a full 150 genoa then the designer will have positioned the center of effort over the keel with that sail flying. If you roll this sail up you are lessening the effort in front of the mast without balancing it aft of the mast which would result in weather helm. As a matter of further diagnosing the problem I would start by reefing the main which should help create a better balance.

Assuming this helps you could then work on methods of de-powering the main perhaps by flattening it and by adding some twist.