What is overstiffness and how do you measure it? I would think everyone would want to transfer the power of their rig to the water with no loss - we aren't there yet.
SOME stiffness is good. The stiffness of a component or complete platform is just like every other feature in a boat’s design; it is compromise for one feature over another. To universally apply “stiffness” as something that is better no matter what is a false premise, same as saying more hull volume, or weight or anything other item is universally better in all conditions.
A telephone pole stiff mast has a very limited useful wind range. Composites under load will flex some and if they do not then there are stress concentrations that will fail in time, unless the structure is just totally overbuilt for its conditions (read weight). There are a lot of water forces acting on a boat and not very many of them are in a useful direction to help our sailing. With a very stiff platform these are transferred to the rig. “Shaking” the rig disrupts the wind flow, which is bad for your performance. So now we dampen the rig or sail or something else to make up for the added “negative” forces imparted with a super stiff platform.
Do not get me wrong, I will sail on a stiffer boat given a chance, but it is not a universal constant that makes everything better.
