fin size

[Keen]

Going into season 4 or my windsurfing career (at least I wish it was my job), I'm just starting on smaller boards now (well not that small but small for me...). I've heard various comments about how fin size can change the dynamics of a board and rig and that sometimes it's wise to change fins depending on wind and sail size and maybe even waves/chop.

Can anyone offer advice on how and why you'd choose different fin sizes relative to sail size, board size, wind, etc... or does this just come from experience. Right now I just have the fin that came with my board. I would not know where to even start if I was going to try others. I see there are different shapes too...

thanks
Keen(er)

[winddoctor]

Hi Keen,

Fins play a huge role in changing the handling of a board. Often you can settle an overpowered board down by simply putting a smaller fin in or visa versa for an underpowered board. This is much less expensive than switching sails. Much of knowing how a given fin will work in your board comes down to experience, but generally longer/ more upright fins will give better lift and easier planing compared to the smaller and more maneuverable swept back fins used in wave boards and freestyle wave boards. Using too large a fin will often cause the board to get squirrely and cause it to tail walk when over powered. A fin that is too large will maneuver poorly and will have excessive drag as well. Too small a fin will cause poor planing performance and will have a tendency to spin out frequently. In general, a fin that is working well for a given board and sail combination should plane up well, turn easily, resist spin out, and create minimal drag. I try to run as small as possible a fin in all of my boards to get better turning and speed at the cost of a bit of early planing and upwind ability. Some sailors prefer to use a very large fin even in small boards to help with planing and upwind ability (at the expense of turning well and higher speeds). Intermediate sailors generally do better with larger fins and as board handling skills and fin sensitivity improve, they get more performance at the high end by gradually going smaller (to a point of course).

There was recently a pretty good table that was on the Starboard site that calculated the fin size required for a given sail size or wind speed. Seemed fairly accurate. Try a search for it. However, there is no substitute for trying different fin combos for yourself and deciding how you like a fin to feel.

[KUS]

You have told me dick: what's your:
board (smaller= under 100L usually wave/bump jump, use mild rake)
current fin type & size (up to kazillion" pointers>=13" for bump/jump>10" for wave)
your weight
intended windrange??

Typically: check this for clue http://www.bigwinds.com/wind/store/fin/ ... egoryID=21
shape:
more rake, better in waves, but less upwind ability, less ooompfh, smooth turns
less rake, better planing & upwind ability, bouncy in turns (gybes the shits )
for better, more efficient sailors, more rake is possible
size (length) bigger people = bigger fin
more size and width the more power, can rely on fin for jumps, less maneuvrability and more difficult gybing or doing tricks
onshore wind requires larger surface area, stiffer fin, than side or sideoff to get out of break and stay upwind (great for crappier sailors like me)
thickness: more flex (bend the tip), the more loose and wave friendly, forgiving slashing, less "stay upwind" and less jump big-air friendly (at this point reliance on board/wave/speed rather than fin for airs = better sailors)

Typical fins for me (heavy sailor):
Nitinat lighter wind -- dick, beer in lawnchair
(or you could use a pointer 13-16" or much longer if you sail barndoors- don't expect pointers to turn at all ....much)
Nitinat bump & jump 11-13" (28-33cm)- these have mild rakes, stiffer, wider
Ocean lighter wind: 28cm wide, stiff wave fin (these have more rake, can be narrower, flexier)
Ocean heavy wind: 22-24cm, less width, more flex

For lighter sailor subtract about 2-3cm, can use narrower, softer fins too, careful as narrow means dick for power, kiss upwind goodbye around here unless you weigh......dick (you guessed it )
Best solution: rent or buy "serious about waves, #1"

[TheLaw]

Kus you confuse me...what is with all the Dick talk. Am I missing something here?

[UnusuallyLargeRobin]

First ignore Kus, he's unusually large, almost phat! 2nd, check out this fin link. http://www.windance.com/info_source/ass ... lector.asp

[Keen]

thanks Winddoc, KUS and ULR (and of course I shouldn't forget to thank dick ). Lots of good info.

KUS, current setup is:
board: Carve 111
sails: 5.3 and 6.2 are my current sails.
Weight: I'm in the heavy sailor category too (190lb+).
Skill level: probably intermediate? planning in straps, trying to gybe (but not very well).

Fin: is 30cm, shaped like the wave fins on that link you sent me. I got the board used so I'm not sure if it is the original. I notice that the new wave fins are much shorter than mine though. I wonder if fin shapes/ideas have changed a bit over the years? Now I'm a bit confused.... Should I be trying a completely different fin? or maybe I should just leave things alone for now until I've got more experience....

thanks again
Keen(er)

[KUS]

If you are local I can lend you a large chord 28cm wavefin to try out (I use it from a 6.2 down to a 4.8 in heavy winds and I still can't believe it ) , for the Nat I would use at least a 30-33 swept pointer/bump & jump but it's powerbox, I think all those Stars are tuttle. Then I have a swept pointer B&J 12" & 13" in tuttle that will blow the doors off pretty much anything out there speedwise, welcome to try those out too.

The 111 is primarily a Nat/lake board for sure, maybe Kook or IV on 6-7.0 days. Yes, your fin can be smaller and gain speed/mobility as you get better at sailing but a board that size needs something to push against. YOu are probably running larger sails on this too. If you got a starboard fin of an early 2000 vintage they cranked out a bunch of loser fins with a really narrow shape which IMHO sucked pretty hard. A C111 generally needs no wavefin.

[mortontoemike]

I'm sure you know al this, but anyway, the recomended fin for the 111 is a 36 cm free ride. I have a Carve 121 and it does pretty well on the stock 38 cm free ride. It's a decent upwind fin and has a bit of sweep so it turns well.

There is a photo of the free ride shape at: http://www.gunsails.co.uk/en/fins_Drake ... deFlow.htm

If you have the stock 36 cm fin I would stick with it for the two sails that you have.

[more force 4]

30 cm fin for the 6.2 sounds about right if it isn't a stock crap fin. If you haven't tried out different fins, it really is amazing how a smaller fin can quiet an overpowered board. If you want more TOW (sail planing while Kus sits on the beach holding his beer and his well we really don't want to know!), the board could definitely carry a much bigger sail than 6.2 but you'd want a bigger fin to go with it.