Hi
I,ll see if a simpler version is helpfull -
The CLR is basically the side underwater profile area ,-
calculated to its center including underwater hull area board area and rudder area , in a cat times 2 hulls,-
The CE of the sailpan is the center of its area point
on most standard type sails take a point from the tack and clew up diagonally 2 /3 of the way up on the luff and leach ,---where they intersect is close to the CE -
generaly that is somewhat balanced with the CLR to provide slight weather helm ON MULTIHULL DESIGN ,-,-
Other factors are the hull fullness. Fine entry bows TRACK and hold a line to weather more than fuller flatter hulls .Also change in hull area as force and speed increase and hull area submersion changes differently in different hull design dependant of deeper fine entry taller bows that submerge more under sail forces than say a very full type hull bow design that may submerge more evanly along its length as sail forces and speed increase.--that of couse changes the hull area underwater profile differently in the two types of comparative designs ,--
Two existing design examples would be the Inter 20 with flat wide 16 in width hull design by station 3 back as compared to a Tornado type hull with very fine deeper bow hull sections .
Also how ce TO clr ,sail design ,--how full or flat the main is and type of mast section --a non rotating fatter mast will cause more air flow turbulence and along with fuller sail move the effective CE back in real terms much more than it calculated area as compared to a rotating wing mast type section and flat sail ,--as per A class cat design for example ,-
Exactly how a design will balance out in helm is always a matter of fine tuning --mast rake adjustment -rudder rake ,ect .
to calc your CLR -take your designs entire underwater hull area -board area and rudder area ,-diagaram it ,-then calc its center .--Sometimes other existing cat designs and models are the best references to determine board placement on a similar design .
this article might be helpfull
http://www.steamradio.com/JSYD/Articles/NESTalk.html hope that helps
Carl
