The more I think of your 36 cm fin, the more I find it way too large with a 5.8 sail when overpowered in 6-7 Bft for your 54 kg rider weight.
For illustrative purpose, this is what I'm using with a 5.4 sail in well to over-powered up 20-25 knots of wind (all 4 footstraps outboard and back):
-Hypersonic 105 (77 cm max width/54 cm width OFO): 26 cm slalom fin. A 32 cm slalom fin is too large.
-Carve 111 (63 cm max width/40 cm width OFO): 26 cm slalom fin. A 32 cm freeride fin is too large.
-Kombat 86 (59 cm max width/39 cm width OFO): 24 cm wave fin. A 30 cm freeride fin is too large.
BTW, I'm on Acid 62 + 4.7 m2 wave sail + 20 cm fin in true 6-7 Bft (25-30 knots wind). The stronger the wind, the smallest the gear should be picked up for a light weight rider to still be in 100% control when fully lit in choppy seas. The Carve 111 is for sure too big with a 4.7 sail for me whereas the Kombat 86 is still barely manageable with a 4.2 sail up to 7-8 Bft (2 front straps inboard and front; single rear strap centered and front. All 4 footstraps outboard and back was just impossible to keep sailing the board trimmed flat & fast).
Last edited by Jean-Marc; 11th March 2010 at 06:23 AM.