I've read the idea of measuring across the board a certain length from the tail but is fin size affected by rider weight as well? A heavyweight needing a larger fin and a lighter a smaller?
I'd use a 7m and 90ltre in 12-18kts but a 100kg guy would use that in 25kts plus?? How does it all relate..
Select to expand quotesboardcrazy said..
I've read the idea of measuring across the board a certain length from the tail but is fin size affected by rider weight as well? A heavyweight needing a larger fin and a lighter a smaller?
I'd use a 7m and 90ltre in 12-18kts but a 100kg guy would use that in 25kts plus?? How does it all relate..
Hi Sue im 110 -115kg i,I would use 7m and 90ltr in 25 to 35 knots . I prefer Pointer fins and in flat water could use 33cm + for speed ,, up to 36 for comfort or hour or chop.I have run 7.8mtr on 90ltr with 38 fin and still had a good session. Fin size is mostly suited to board width and Sail Combo not weight.
Most of my Boards have one fin thats suits better than others.
As an intermediate sailor ,poor technique / heavy dude. I find fins make a huge difference. The OFO measurement is a starting point. The more i experiment on fins for EARLY PLANING im finding i should choose a fin 5-7cm longer than OFO. This will get me planing n mostly keeping up with the lightweight crew. Got sick of the lightweights zipping past me. 57cm fin is a bit of a wrestle over 18kt. 
But gets me planing real early.
Suits GB conditions well.
For me most boards of same width are similar & I tend not to think volume as width can vary. I also prefer pointer fins but the less powerful ones, at 115kg a 60w board 7m I will use 33 fin, 31 or even 29 in flat, rarely would I go up to 35 fin, I'd rather change up a board size. In big boards/light winds i'm definitely on about 2/3cm longer than 85kg guys but that's just me not weight as I used same sizes when I was 85kg also.
What about using 45 degree weedies compared to a pointer? Same size or a bit bigger?
