I put a very strong digital rudder servo in my boat and bought one that is so equipped. I wonder if anyone else - I know of one - is finding that in order to not have lee helm and to give the boat some slight weather helm so it wants to point going upwind, they need to move the mast and jib both an inch or more aft - versus 25.5 mast and 7 3/8 with 3 3/4 inch jib boom offset - to induce good helm feel.

From talking with my cabin mate, we decided that apparently the strong rudder servo might be making the rudder act more as an extension of the keel than a weaker servo, thus moving the CLR (center of lateral resistance) aft.

That large amount of CLR shift sounds improbable, but I figure the boat will tell me out on the water how it wants to be set up and tuned.

Scott

Scott, are the weights of the servos and new linkage comparable? It could be that the digital servo weighs more, which would squat the rear of the hull lower in the water...just enough to change the helm and your "usual balance point".

You could try moving the rudder servo further forward on the board to see if the helm returns more to "normal", or move the battery a little further forward.

Just a couple of points to ponder.

Steve

Scott, how strong is "very strong"? What is the torque rating and servo Model?

Scott

Which rudder are you using to have that effect on the helm.

My big square edge or the standard cut out and rounded top and bottom edges.

This makes absolutely no sense to me at all. The force on the rudder should have nothing to do with the balance of the boat. If the boat was balanced before with just a small amount of weather helm with the old servo, then the new servo should not change one thing about that. The boat will sail how it wants to sail if tuned well. If you are hard on the wind and let go of the rudder, the boat should slowly come up to windward in 4-5 boat lengths. That is good weather helm. Faster than that and you have too much weather helm and if it keeps tracking straight you have no weather helm.

To keep the boat pointing with weather helm, you need to put in a little rudder. This is the only thing I can think of that is changing. The new servo is so strong that it requires very little stick effort to overcome the load on the rudder, while your older weaker servo needed more input. It seems to me the problem may be to get used to the feel of the new servo or to try and change the throw on the stick to give you the feel you want. The tech guys can tell you how to change the radio controls if you don't already know how. I admit that I am not savvy on that stuff, but I know it can be adjusted.

Moving the mast aft seems like the wrong thing to do to fix this issue.

I appreciate the questions and comments. I am realizing there are a lot of variables and I will just keep working on the setup for the second boat.

Scott

Have to agree with Joe. I did the same thing and after a few sessions got used to the new servo with no mast change. The newer more powerful servo does mean alot less input required to the point where even tacking I use 1/2 the stick I used to and very minimal stick movement for weather helm

Just a had a tuning session today with another local who uses the older servo and I struggled with his as it required more helm for the same result - i.e. movement of stick to get the same response as my one.

Also agreeing with Joe on this unless you put the old servo back in and suddenly the boat is balanced. Just a truly odd idea that the output torque is somehow effecting balance.

Nothing else is different other than the Servo. My guess is that the rudder is not moving freely and the servo is not centering or the servo itself is not centering. All has to be very very free moving in order for the rudder to center after you let go of the stick.

BTW, your rig position, jib tack position look right so something else is off.

Agree with last posts.
One last thought- you tightened all the connections and there is less "clack" or play in the servo arms and tiller arm so what you dial in stays put.