In my experience, wind speed can be a factor in the amount of weather helm felt. Remember that weather helm is not solely determined by the amount of rudder rake. The helm is really determined by the overall fore-aft balance of the sail plan in relation to the underwater forces generated by the hulls, rudders and daggerboards. So, mast rake and sail trim are quite important.
For example, even when your boat felt balanced on a 10 knot day, if you were to sheet the main in tight and completly luff the jib, you would experience excessive weather helm. The reason being that the center of effort of the sail plan has now shifted aft of the balance point of the hull, so the boat naturally wants to turn into the wind.
So, if your helm is normally balanced, but you felt excessive weather helm on a windy day, it is likely that your overall sailplan was out of balance. Perhaps you eased the jib sheet. Perhaps you under sheeted the main (which can cause the leading edge to luff moving the CE back) - instead travel out and sheet tight. Perhaps your downhaul was too loose - also allowing the CE of the maisail to shift aft. Or maybe you set the boat up with more mast rake.
Or, it is possible that your rudders are raked slightly too far back and the increased power on the windy day caused the helm to be more noticable - you could try raking the rudders under more.
sm
|