View Full Version : Fin guide

12th May 2008, 05:14 PM
I'm looking for a finguide which tells me what different sizes/shapes does in general. I mean, what happens if you use a fin that's too big, or which fintype is the fastest.
Not any advanced, just in general. Can anyone please contibute with their knowledge ?

12th May 2008, 07:27 PM
1. Straight fins for racing (slalom, speed, or Formula). Not very user friendly
2. Very curved (swept back) fins for waveriding. Good maneuverability.
3. Freeride fins, curved but closer to 1. More user friendly than 1.
4. Crossover, freestylewave, bump/jump, etc fins. A little straighter, and better for blasting than 2.
A lot of combinations of the above.

If you have too small fin under your board, you will go fast (once planing), but you'll have trouble:
-getting on a plane
-pointing upwind
-with spinouts probably

If you have too big fin, you'll plane easily and point well, but you'll also have:
-lower top speed
-control problems, board tipping over, tailwalking, etc.

Edit: is this a windup? ;-) Sorry if it's not.

12th May 2008, 08:40 PM
And for size GUIDE!!!!
Sail size (in metres) x 5 then add 3

6 metre sail.
Gives 30
add 3
Gives 33

Sceamer`s fatguide to fin size is spot on.

What`s difference in spelling for wind up (as the wind getting up)
and windup (as you do with a windup clock)

Wind driven clockwork clock could be
a wind up wind up clock ???

12th May 2008, 08:53 PM
If you're looking for a fin, some of the fin shops can give good advice.

Another variable is the board the fin goes on. As a fairly extreme example, on a 6.5 sail I use a 30cm freeride fin when on 96L Kombat. With the same sail, I use a 46cm race fin on a 135L freeride (wide tail).

12th May 2008, 10:50 PM
Are you talking about Tabou Rocket 135 maybe? 46 sounds big, even for a wide board.

12th May 2008, 11:10 PM
There's an automatic fin guide on my windsurfing equipment calculator.


And some brief discussion of different fin shapes on this blog post.


13th May 2008, 12:13 AM

How did you make that calculator? Consulted/interviewed a thousand sailors? ;-)

I think there are some adjustment to make as Mike says. For example: you could use a 7.3 sail on an iSonic96 (59 wide) and then jump 3 sizes to iSonic122 (75 wide) with the same sail. Obviously you'll need a different fin.

That said I think it's an excellent, if a bit rough, ws gear guide. For someone without enough experience with different gear, it will sort them out.

13th May 2008, 02:36 AM
Are you talking about Tabou Rocket 135 maybe? 46 sounds big, even for a wide board.

Its a 2005 JP 135L X-cite, tectonics fin, 6.5 Retro. It's a new board/fin combination for me this year & it's very sweet, especially when very powered on fairly flat water. I actually got the fin to go with the 8.0, but it's fastest with the 6.5.

13th May 2008, 03:38 AM
Screamer- I made the fin guide based on the fin-size / sail size recommendations on the True Ames fins website for different styles of fin. I.e. I mathematically correlated the midpoint of the recommended sail range of a fin with its size, and used the data from those regressions to come up with predictive formulas. If you look at the spreadsheet and scroll over to the right, you can see the "chicken scratch" calculations that went into the formulas.

13th May 2008, 04:05 AM
A basic fin guide / formula is a good starting point.

With more experience you will play around with fin sizes and types depending on many variables.

Is there a particular board and sail size matched with your weight, sailing conditions and style that you would like a fin suggestion for to maximize your desired performance?

13th May 2008, 03:11 PM
Thank you all for your answers

It's not to a certain board or sail. I just want to know in particular.
What I can read here is that you almost have to try a fin to know it's good (or know a person that has tried it), is that correct ? Doesn't seem to be any rights and wrong as long as you're in the boards recommended scale. Just a matter of former experiences and what you feel is good for you. Am I way out here ?

13th May 2008, 05:31 PM
No you're not way out.
Are you swift? ;-)