I’m starting a 6’2 shortboard and its my first shortboard and I had some questions regarding fin placement ( I’m using glass-ons). First how much toe and cant should they have and how do you measure the cant? And also where should the fins be placed?
Finally , how much rocker should I have nose and tail. This is my first performance board so up untill now I’ve only done low rocker boards where everything didn’t need to be so precise.
Hey JerseyGrom,
fin set up depends upon the board size and rocker. Here is a general guide: Rear fin 3-1/4" up from tip of tail. This is measured to the REAR edge of the fin. Front fins are 11" up from the tail tip as measured from their rear edges. This point would be about 1-1/8" in from the rail. These fins point about 2" off the nose; for the right fin that means 2 " to the right of the nose. If you don’t have a long straight edge, tape a piece of string to the fin dot and project as described. This method will better match the length of board which varies as does the rocker. Lastly, the angle of the fins should run about 6 degrees off vertical (be sure to compensate for things like concaves which throws your “vert” off). Vertical is with respect to a flat bottom as is the 6 degrees.
As for rocker, when you are starting out on a shortboard shape, it really helps to know the blank. What are you using? Then, where are you placing the board on the blank, all the way back, forward? This will affect your rocker outcome when starting out. Once you describe the blank and placement, then I can suggest the amount to alter the existing rocker so you will meet with some sort of success.
Good Luck,
PlusOneShaper
+1’s got the goods on fins…a definitive professional and super generous too…
some basic advice on rocker from someone who’s tried many things…
how do plan to use the board?
what common conditions?
your style?
the most basic approach is lower the rocker for more speed and drive out of turns…increase it if you want to surf like Slater in world class surf. Rockered out boards are too slow for most surfers…you gotta know how to really pump’m to make them go or surf good waves…bottom line for me is modern fish rocker works best in gutless EC surf…about 4.5 nose and 2 tail with a single concave peaking between the feet…more speed = better, easier turning…super fun majic
thanks a lot guys , im getting the blank today from joshmosh and shaping it tommorow after i score some of this head high swell with offshore winds in the morning!
Hey Jersey -
Fin placement is one of the key things to getting a board to go right — you need to learn about this from trial and error…get 4way fin systems and you can adjust your fins till they feel just right and learn loads in the process.
Best of luck!
Be sure and post a pic when you’re done. Hey, and your old man was a pretty cool guy.
I’m currently building a 7’0" (12 1/4" X 21" X 15 1/2") big boy thruster. The board has a single to double concave bottom. How does the larger board affect your general rule for fin placement ? Thanks! -mv
Hey Vern,
definitely the above numbers will have to be changed. There is a length relationship with fin placement, BUT there is a type-of-board/performance-requirement sought by both shaper and rider; and this mixes things up a bit.
In general, but you can’t quote me on this is, the longer the board the more spread apart your cluster. This will be a differing rule for a speed egg vs. a gun vs. a big boy thruster all of the same length.
I don’t know your rocker or the outline but from doing trial-and-error for so many years, I can just look at a board and get pretty darn close with the fin location. Also, how heavy is the rider and how fast is the surf? If you have an outline photo and a rocker photo, that would really help.
All that aside, rear fin about 3-1/2 inchs up from the tail tip to the rear edge of the fin. Front fins around 11-1/4 up for a wide-tailed board and 11-3/4 up for narrower gunny-er shapes. Front fins probably about 1-1/4 in from the rail but as little as 1 inch for a “fun gun” shape. Point the fins about 2 inches off the nose (1 inch off, if the waves are on the slow side, and about 3 inches off the nose for more “J-bay” style waves… Lastly, tilt the fins out about 6-1/2 degrees from a flat bottom (compensate for concaves as they throw this measure off) and less tilt for bigger surf (1/2 to 1 degree) and the opposite for small surf (IN GENERAL).
This is just a guide, I don’t know your template, fin flex rate, anchoring method, or even intention of the board. Again, a couple of photos go a long way.
HTH,
George
Hey Guys
There is a lot of good info on dimentions,fin positions and lots of other good stuff at http://www.naturalcurvesboards.com/PDF/SurfboardDesign.pdf they actually feature the dimentions of a 6’2 shortboard.
Check it out
Thanks +1,
To expand, the shape is kind of a typical shortboard. I’ve posted some pics on the following thread; http://www.swaylocks.com/forum/gforum.cgi?post=221330;#221330. I’m not sure how much you can see from the photo’s. The stringer rocker is 5 1/2" at the nose and 2 1/2" at the tail. I will be using fcs and at 6’2"/200 lbs I’m considering GAM’s or GPR’s, but am open to suggestions all around. I really appreciate your placement and cant recommendations. Thanks! -mv