Mark,

Harken have a calculator on their website that gives sheeting forces for a given sail size and windstrength (http://harken.com/calculators/MainsheetLoading.aspx), but the point is that is pretty irrelevant as the maximum forces are more to do with righting moment than sail area or windstrength. Also there are both sailing techniques and rig designs that allow you to overcome higher sheeting loads.

The whole point of me starting this thread was to see if people were interested in an F12 design that could accommodate a larger age range by having different rigs like the BIC dinghy does. I thought that people were interested in this. I am not trying to drive the F12 to be a kids boat only I just would rather it accommodate everyone.

Gareth