I have been having helm issues my boat would fall off really bad so i messed with my fore-stay, i loosened it up allot then went sailing! Before the boat was falling off re bad now it rounded up with it real loose! so I tightened it a little but still real loose now it is doing better but i think the forestay is really to loose yet, hmm I know its not a Hobie but does anyone have a rule of thumb? if i had chop in the waters i sail i would not go out like this!
Forestay tightness will not have much effect on helm. Two major adjustments will help.
1) Mast Rake. Sailing under way, the sideways resistance is provided by the daggerboard(s), sideways force is generated by the sails. If you rake the mast forward, you move the sideways force generated further in front of the primary resisting force (the daggerboards) and have more lee-helm (your condition here). To reduce lee-helm, rake the mast further aft to bring the sail plan closer to the daggerboards or even aft of the daggerboards to generate weather-helm. All other things being neutral (see #2), a slight amount of weather-helm is desirable because it puts your foils to their best use (allowing both the rudders and daggerboards to generate some lift).
#2) rudder rake. This affects how the boat turns and how how the tiller feels. It is often confused with performance tuning of the foils - it is not. Rudder rake is used make the helm feel more or less neutral but the effeciency of the foils through the water depends NOT on what you feel in the tiller, but what forces are acted on them by the mast rake/sail plan. If your rudders are raked such that the center of effort is in front of the pivot axis (the pintles), the rudders will react opposite of the sail/daggerboard remaining force (weather-helm or lee-helm) and neutralize it somewhat. If the rudder rake puts the center of effort of the rudders through the water BEHIND the pivot axis, the feel of the helm will be more affected by the sail/daggerboard reaction.
To make a clean setup, set your sails to sail to weather, have daggerboard(s) fully extended, and raise your rudders clear (or nearly clear) of the water. The boat should round up into the wind. If it remains neutral or rounds down to lee, you need to rake your mast aft. Once you have a decent amount of weather helm, now adjust your rudder rake until your helm feels like you want it to. If, with rudders now down, the boat changes and turns to the lee, rake your rudders more aft - i.e., further away from being under the boat. If, with rudders down, the boat turns much harder into the wind, rake the rudders forward. Most people like their helms setup with just a little weather helm. It gives boat boards the opportunity to work and is safer (if you should drop the helm or something break, the boat rounds up instead of bearing away and accelerating).
