I have always used the fin which came with my board.
Should I change fins when I change sail size or what?
Are they as important as the sail?
How do you choose which size/ shape fin to use?

Don't know much about Fins, but I do see some nice looking Swiss and Swedish girls about.

I've also read that you should measure the board width at the "One foot off" point from the tail of the board and that size is the smallest fin you should run on that board... Read that on the starboard forums but I've never really tried going smaller than that in real life.

Windxtasy said...

Now I've worked out that my fin is larger than what they recommend for the sails/ conditions etc by 2 - 5 cm depending on the sail. What would that be doing to the board's performance?

You mentioned on the other thread that your board got scary fast. This is probably becasuse you are over finned. When you are really powered up(the windy days) your fin will start to generate more lift that you can hold down. This will cause the board to rail up(windward) and in some cases tail walk(nose lifts).

This can be solved by just putting on a smaller fin. It's simpler that rigging a smaller sail.

When your back foot is in the straps you have only so much leverage over the fin. The faster you go the the more lift the fin will generate. So in stronger wind where you will be going faster, you should use a smaller fin.

Unfortunately there is no simple rule. There are just too many factors to consider. Fin style (u.s., powerbox, onshore/crosshore, full draft fins, weed, slalom, freeride)
and board style, ability and conditions that also play a major part. And most importantly, how you personally want the board to feel. Really, its just experimentation to find what roughly works for you. The fin that comes with it is usually an ok starting point. You can get a rough idea, but then you will need to experiment with a few to give you a better idea. Unless you can borrow, then this is expensive. Some shops have a bunch of second hand ones, or your mates might. You may be able to borrow these to just get a rough idea on how that style or size works for your set up. Once you tried a few, you will be able to imagine what it will be like by changing slightly.

Also, going back to your question, should you change fin with each sail ? Slalom racers tend to have a whole quiver of fins. And probably put as much importance in these as to anything. Some people on free ride boards may have 2 fins for the opposite ends of the wind conditions, which is roughly a smaller fin for windy and small sails, and a bigger fin for the rest of the time. A lot of wave sailors will just find one that works for what they want, and the conditions they use that board in, and leave it in forever.

Fins are the enemy and should be ruthlessly punished by filing them ever smaller...

www.peconicpuffin.com/the_peconic_puffin/2007/10/freestyle-fins-.html

Might not be suitable for all sailors though!!!

...especially given the insane attention to detail the speed boys put into their fins. I can't rib 'em too much though - Matt did an epic job on sorting out one of mine after I totally stuffed it...