Found this on an american Wsurf forum.http://www.vims.edu/general/sailpaddle/SailCalculator.xls
I'm not sure about his board size calculator:
Smallest that can be uphauled with moderate skill 110
I can easily uphaul my 98l board. I'm 80kg and my skills are moderate. His formula is weight + 30kg. I reckon it's more like weight + 15 or 20.
the "weight + something" will often depend on whether you are sailing on fresh or salt water -> in fresh water you feel like you are loosing about 5-10% of the volume.
Based on the website mentioned in hte spreadsheet, this guy sails on both water types, so the size is not unsurprising.
