Swing keel / centerboard depth effect on Lee or weather helm

[IASailor]

I read and a thread that mentioned how adjusting a centerboard could change the effect of Lee / weather helm. I must admit that this idea greatly intrigues me and I'm wondering if we can start up a dialogue here regarding the effect. How does the depth of a swing keel / centerboard effect the weather / Lee helm characteristics of a sailboat?

I have always assumed that the swing keel on my Catalina 22 should be fully down unless sailing downwind. Even then I keep it down for the righting movement.

 

[capta]

A centerboard is a triangle on a pin at the forward end. As you lower or raise it, it moves the center of lateral resistance forward or aft which can affect lee or weather helm. Some boats even have two boards, one in front of the other and this can radically affect things like tacking and down wind tracking.
I know nothing of swing keels, as I have never sailed with one.

 

[rgranger]

Absolutely correct. If you think of your keel as an axle that your boat can rotate about and the pressure on your sail is a dude trying to rotate your boat into or away from the wind ... then swinging the keel up or down affects where the axle is attached to your boat. If you align the axle with the dude pushing... then the boat won’t turn... I.e. a balanced helm