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G.O’Rilla wrote:
Not just same hull shape, but also similar weight distribution. If those two are normalised and proven to be so then I and many others will be happy

It is not just the hull shape and the position of the centre of gravity (CG) that are important. More important then the position of the CG is the moment of inertia, or rather the position of the axis of that moment. That determines the roll and yaw characteristics. Of course it is true that if the position of the CG is changed the inertia changes as well, but we should be looking fort similar inertia characteristics in a new boat.

Here is how the Finn class determines the axis of inertia and the CG by a simple swing test: http://www.finnclass.org/interestingstuff/swingtest.htm

Please bear in mind that such a test is not needed for every new boat, only for the first one of a series. The results should be compared to those of an existing boat. For that we would first need to establish what a Wayfarer is…..

I strongly believe that the roll and yaw characteristics (defined by the moment of inertia) are as important as the hull shape. They determine how the hull behaves in waves and wind. In other words; how the the below the water line hull shape changes (A/O changes in the water line length) while the boat is rocking about. I also believe that this effect may be one of the main factors why our different marks behave differently.