hey elmo why do you think MFC recommend the 39 cm weedy for 6.5-7.5cm sails? i would have thought that would be more like the equivalent of the 44cm pointer and for sails up to 8.3m? the choco 33 is supposed to be suitable for 6.5-7.5 sails.. what the?!? which brand is the black and green ones to be avoided?
Well my theory is that there are 2 types of weedies. 1 where a mass produced foil is boxed at different angles, this will produce a smaller thickness to flow ratio the greater the angle off vertical.
2 where the fin is designed to have the optimum thickness to flow angle regardless of rake, so these fins are a different foil for every rake angle.
At 45 deg this can mean a 40% difference in thickness to flow ratio between the 2 types.
The first type will be less powerful than the second, so will need to be bigger for the same sail size.
That's why the guys here reboxing pointers into weedies are choosing the thickest fins they can find.