At the risk of sounding ignorant with all you "fin-swappers" out there, I have a question: I bought the 9'8" Starboard recently (love it, great for my size, 174 cm & 73kg), & set the centre fin as far forward (towards the nose) as it would go, as my understanding is that this would provide the loosest set-up for the small reefies we ride around Cottesloe. I'm thinking that I'll push it towards the back when i go down south (although on my first surf with it took it out south of Margs in head-high fat surf with the current set-up---seemed to work fine). However, one of my fellow Cottesloe SUPers reckons the board will be looser with the centre fin positioned towards the tail??!! I noticed that Robdog has his in the centre position. Any comments?? Ta!

Gracias rodriguez, that's pretty much what i thought! My Cottesloe mate has obviously had a "bum steer" ......sorry....pathetic attempt at a pun.

FYI ( not my explaination) from a blog but its realatively accurate.

I have been riding a 2+1 fin setup for ever, so that's really what this applies to. By 2+1, I mean two smaller side fins and a longer center fin. The theory is that the side fins keep your board from slipping sideways down the face of the wave and also creates a pivot point for increased maneuverability. The center fin stabilizes the board, and controls how the water moves under the tail of the board. Since the tail of the surfboard both holds the board in the wave and contributes to the performance of the surfboard even the slightest changes can truly make a world of difference.

Unless your fins are all glassed on, you probably have the ability to slide the center fin forward or back. Finding the sweet spot for this center fin is what we're all looking for. As I mentioned before, generally, when you move the center fin forward the board turns quicker and when it's moved back, the board is more stable and rigid in it's line of travel. When you have side fins on a board you need to take into consideration their placement as well, when you decide where to put your center fin.

I'm no expert on hydrodynamics but I do know that when we ride waves, there is water moving from the front to the back of the board as well as side to side. If there's too much turbulence between all the fins, the board is going to feel stiff and not perform as well as it could. There are three boards of different shapes that I've been toying with fin placement on and I've found the same results for each. I may change my opinion about it later but, this is what I've come up with so far.


Fin Totally Forward: When I put the fin totally forward it usually overlaps, or lines up right with, the rear of the side fins so that if I look at it from the side, there is no space between them. Here's how this has performed for me. This setup feels stiff to me, unless my feet are in just the right spot. However, as soon as my feet find that spot, it turns on a dime. In fact, it turns a little too much in my opinion, almost so that the board almost spins out on me. Also, I'm not able to carry the speed through the bottom turn on a larger wave when the fin is extremely forward. It sort of feels like the board puts on the brakes before making a super sharp turn. This is sweet for a small to medium size wave, but on a big wave, I'm looking to carry the speed through the bottom turn. On the topic of speed, it seems to me that the board isn't quite as fast with the center fin all the way forward. My guess is that when the larger center fin is clustered too close with the side fins, it creates too much turbulence in a concentrated area, slowing down the board. I have to mention along with that, that the problem can probably be remedied by adding a smaller center fin and some larger side fins. Infinity Surfboards has mastered this setup with their "Cluster" fin setup. I've ridden an Infinity longboardboard with the Cluster fin setup and it's nice. Their boards were designed to have the fins clustered together and they perform great. Hey, move the fin all the way up on your board and see how it performs for you. It could be the magic spot.

Fin Far Back: With the fin far back, the board is fast, stable and straight. I'll turn almost any board into a straight shooter. This may ideal in a big, fast wave where you just want to drop in and head straight down the racetrack. To turn the board, you'll really have to get your weight back on the tail of the board to sink it and redirect your momentum. Careful. My friends more than once I have stepped right off the back of the board only to see the tail of the board pop up and bruise me in the thigh...narrowing escaping a castrating...I mean catastrophic incident. I have tail blocks now and more importantly, I do all I can to intuitively know where the board begins and ends.

The Magic Medium: so, far, every time, the magic spot has been where the leading edge of the center fin is about 2 inches behind the trailing edge of the side fins. I seems that the spacing allows enought room for the water to flow around the fins so the board is fast in the straightaways, and is far enought forward that the board can turn quickly and controlled. The board maintains speed throught the turns and accelerates quickly when I need it.

You're probably wondering what kind of fins I've been using. The side fins are Future Fins SB2 and for the center fins I was experimenting with were a Bonga "Da Fade" 8.0" and a Flex Fin 7.5", both by Island Fin Design. We'll, that's my 2 cents on center fin placement. If anyone has found the magic fin setup, let me know. I'd love to give it a shot. Happy Surfing

Phill

I'll keep it short and sweet, fix your centre fin 40mm from the front of the fin box,you get the best of both worlds,drive and lose! oh 7 inch fin would be perfect
in head high surf!but any bigger add another inch

mac