Ehhh. One has to remember that the situation is a 3D situation and not merely a 2D one.

Example. In 2D nearly all monohulls will appear to have lee helm when going straight downwind. However as good as all have weatherhelm at this point. This is because the boom is so far out that de CE of the main is so far to the side of the point of drag that the net result is weatherhelm. It is entirely possible to have a boat that can move from weatherhelm to leehelm and back to weatherhelm when going from a beat to straight downwind sailing. In short the 3D pictures is very important and with monohulls even the heel of the boat can give rise to great differences. Another example. A given monohull can have leehelm on a straight downwind run in light air (hardly any heeling) and transition to weatherhelm in a guts (large heeling) when still sailing on the same course.

I agree that Darryls methode is a good grafical methode for finding the CE for the situation where all the sail are sheeting as good as parallel to the centreline but be very careful when extrapolating these result to other course that may have the sails sheeted significantly differently. Of course the spinnaker issue is one of such apparently contradictionary situations. Where the grafical methode suggest alot of lee helm being introduce when in reality this is not really the case.

Regards,

Wouter