How to Make a Custom Freestyle Fin for Your Windsurf Board.

Cutting down your fin is often considered a kind of “right of passage” along the road to the Nirvana of windsurfing freestyle. Today we’re going to look at how to do it as we convert an old (and fairly well worn out) wave fin into a short custom freestyle fin.


Why is a short fin useful? The super short fins used by freestylers allow them to slide thru the spinney rotational moves like Spock 540s without catching and tripping the board. The downside is that they give less lift and may make the board less easy to carve for the more “old school” tricks like carving 360s.



Since getting my Tabou freestyle board I’ve started trying to do Vulcans. At the moment I’m at the point that I can get the pop and start to get some rotation but then either land across the wind and  trip or go flying “out the back door” .Alternatively I sometimes land and the board somehow slews back to the original direction ( so it just looks like a dodgy downwind pop ! ). I hope that by using a smaller fin I should be able to carry on sliding, continue that rotation and be able to start working on the hand change. Perhaps I should continue with my existing 21cm fin because it’s not excessively large. But hey, I’ve got on old fin that hasn’t been used in years and I fancy experimenting.



How short ? Most production dedicated freestyle fins seem to be 18cm but I’ve seen people using fins cut off shorter. I could just cut off the boards existing fin to 18cm but I don’t want to risk messing up a perfectly good fin for this experiment and potentially have to fork out 80€ on a brand new fin if I don’t like the results. So I’m going to cut down an old 19cm wave fin. The idea is to remove the trailing back section and round it off to an elliptical tip. I’ve marked out my design in pencil on the fin and once I’ve removed the trailing section of fin (to improve tracking when sliding backwards)  I reckon I’ll probably end up with a 16cm fin ! This is slightly shorter than I would have liked but it’ll be an interesting experiment.  I’m really thinking that If I can still get up wind with such a small fin and carve and pop ok then even if I end up buying a production freestyle fin from someone like Tarifa Fin Company then at least I’ll be doing so in the confidence that the fin will be big enough (something that worries me a bit at this stage – even tho I am using my existing 21.5cm fin with sails up to 6.5m whereas most freeride boards come with a 35cm fin for use with this size of sail, the step down to 18 or less still seems pretty drastic)



Why an elliptical tip ? A lot of freestylers seem to just cut their fins off strait and leave it that way. In fact that’s what the previous owner did when he cut down the fin which came with the board from 23cm to 21.5cm. But all the professional designs I’ve seen have rounded or elliptical tips ( check out MFC , K4 or Tarifa Fin Company fins and you’ll see what I mean ) . I think that this is to reduce turbulence especially when the board is carving and drag. Apart from rounding the tip off I’m also going to thin the tip off for the same reasons and to hopefully reduce unwanted “spinout”. I think that one good thing about cutting down already short fin is that the chord thickness is fairly narrow whereas if you cut down a longer slalom fin you have the advantage of a more vertical foil (early planning) but the fin ends up very thick and stiff. I’ve also noticed that both K4 and Tarifa fin company freestyle fins are swept back anyway compared with the MFC freestyle pro (which is pretty much the industry standard). So hopefully this will work out ok.

                           A "Proper" Freestyle fin from the Tarifa Fin Company 


So enough of the theorising and procrastination. Let’s get down to work !



Step 1 – Mark out the fin and cut it down.



Two straight hacksaw cuts get rid of the bulk of the material. A couple more cuts and we have the basic shape.

 Step 2 – Round off the outline and thin down the tip of the fin

First we round off the outline with sandpaper backed with a plywood block, and then we mark the centreline of the foil with a pencil line to help keep everything symmetrical as we thin down the tip. We then use coarse then fine grade sandpaper to give the fin the desired profile. NB. I have actually done a fair bit more sanding since this photo was taken but unfortunately forgot to take another photograph of the finished fin.

Step 3 – Seal the fin

Since this is an old fibreglass fin I decided to seal the bare fibreglass with superglue. A G10 fin wouldn’t need this final stage. The bared material is painted with several coats of superglue. We then leave it to cure fully overnight before sanding the surface smooth with 240 grit sandpaper.

Step 4 - Go Windsurfing !

Hey presto a new custom freestyle fin! Looks like it’s going to be windy this weekend so I’ll be able to check it out and report back.

                  Another "Proper" Freestyle fin this ones from K4 Fins in the UK