Hello Sail7seas, Here's what John Pierce, builder of the Stealth, had to say about "shared lift and CE migration and how to live with it".
Bill
Yes I agree, I have always used the shared lift idea in my boats, both those I build and when I sailed T's and others, Whether the boards are forward or not, the same effect can be got with what ever size boards/rudders are chosen, its just about the position of CLR against CE of the rig, however with existing classes obviously board position is fixed.
With the boats we build, we go down the raking the mast back route to load up the rudders, and rake back the spinnaker luff, however we do have large rudders, one thing that compromises most boats that now carry spinnakers is that most class rules limit pole length to 80cm beyond the bow. John Pierce and I agree, Sail7seas. We are on the same page. I don't know why one poster wants to say that when you put an additional sail up in front of the mast on a pole that sticks out well beyond the bows and has an area equal to or greater than the base sail area of the boat, it does not move the center of effort forward significantly when in use. This is putting your head in the sand. It is not a farytale. It really happens. >Loading up the rudders by mast rake or loading up the rudders by placing the daggerboards forward both lead to the same end result.< This is a true statement but incomplete. Raking the mast back or moving the CBs forward will trim the boat out properly with spinnaker up. This is fine, AOK. The problem is "what are you left with when the spinnaker is down and now you are sailing to windward sloop rigged"? If you have chosen the "rake the mast back route" you are left with an overloaded rudder and underloaded centerboard and this is draggy underwater. If you go with "move the centerboard forward and downsize it and upsize the rudder", you eliminate leehelm with spinnaker up and the centerboard and rudder are in balance, less drag, sailing to windward with spinnaker down. I'm getting out of breath saying this, Sail7seas. I hope we are communicating. I have no experience with model boats and model boat testing. On any sailboat there are many interactions with changing mast rake. It is a complex subject. Good luck with your model boat racing, Bill
