Originally Posted by Roger
some of it depends on the type of board, the sail size range, mast foot position etc.
Also, 34 cm to 44 cm on a 114 liter board sounds a little extreme to me.
Where do you run your mast foot....and why?
I agree with roger. Sail and mast foot position matter a lot on how you sail your board. Forward is usually a more comfortable position in my opinion.
Further more, 44 cm fin on a naish vector.... i find that a bit overexaggerated. These boards come with a stock fin of 34 if i recall correctly and my guess is that a 38 cm freeride fin would be it's comfort max.
I use my flow (113 L) with fins between 28 and 36 cm. 28 being its utter comfort minimum and 36 it's utter comfort maximum. Bigger fins will give you a very unbalanced ride which might make you get into positions that don't feel natural.
Also, my guess, the pictures you're looking at are pictures of guys getting into a downwind plane. it's not uncommon for a surfer to bend through his back leg and strech his front whilst completely hangen onto his sail as to get into a plane. This position enables almost full weight to sail transmission when using a waist harness and also, the weight thats left is based fully on the front foot limiting backfoot pressure and maximazing the planning surface. Once you're planning upwind, usually, both legs are streched or, like you say, the front leg is mildly curved as to get maximum frontfoot weight transmission whilst placing the sail slightly backwards to get more upwind controle.
thats my view of it all