Harrow,

28-29 sounds a little big for an 85ltr. I tend to use a 22 in my 85ltr board.

Firstly I think you have to address what is wrong with the current fin? Doesn't sail upwind well, it's 'slow', doesn't plane early? On an 84L wave board you are usually using wave sails in the 5-5.6m range. Running a big fin on sails of this size without a LOT of wind is a ticket to not plaining early. The technique used to get a wave board on the plane early is way different than to get a formula board on the plane and relies very little on fin size, so much so that you'll plane earlier with a smaller fin, imo; you might however struggle to hold ground.

In summary if you're using this board with 5-5.6m wave sails and you run a 28-30cm fin you'll find it very 'draggy' and slow; a 25cm fin is perfect for those sails, i'd even go 22 but i'm light. If you're using it as a slalom/speed board with bigger race sails then a bigger fin might be the order of the day to hold the sail power.

At the end of the day though a bigger area fin doesn't necessarily mean you can apply more fin pressure, after all lift increases with the square of velocity ;)

what ever you do... don't lend the board to LJ... once he had a go the only place it will go fast is the dumpster.

I'd second Al's comment re the JP fins only being so so... my biggest problem with them has been durability. Personally I don't understand why JP doesn't include better fins with their boards. You get about 10 to 20% more speed out of the 84/91 FSW with a decent fin.

THis is true for certain, Luke 'Skywalker' Johnson he go crazy with excite and speed of JP 84 FSW.
He go so fast and get so excited he forget board is not his and unleashes double forward attempt on first run.
This look very impressive for sure yar, but this board is not for him and one must pay price for youthful exuburance (kookyness)especially when on someone elses gear !

As for fin, I agree with anything from the Maui Fin Co range being of the best choice for working in this board. You must be of trying the Move 27 MFC for some serious speed on this board

JP fins that came of the standard with 2006 and 2007 model boards are being of better performance than earlier JP fins for sure
Kremlin

Just to go slightly off topic, I have an MFC wave fin and I think it's useless (in my board). The stock standard fin (a naish one) works so much better and if I use the KA fin that I won on this forum the board makes a freaky cracking sound...

Harrow, speed comes from so many things - rigging techniques, sail type, sailor ability, fin length, chord, thickness and rake, matt v's glossy bottom to the board, wind strength, chop, tide & currents.

Have fun!

Hi Harrow,

Got a Naish Freeride 24cm fin in today, and also have the F2 style 27cm available.

Windsurfnsnow

Hey Harrow,

Ask the guys at your local if they've got a spare fin to chuck in your board for a run or two, so you can get a feel for what different sized fins do.

I tried a 37cm Select fin in my 84l JP Freeride a couple of weeks ago, felt a bit weird, like the board didn't want to lean over as much as it should. When I went back to a 31cm (my smallest) it felt a lot looser. In the end the only person who knows how a particular fin performs on your setup is you, so experiment and make up your own mind.