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Suggestions on fin setup 8'6 longboard

PostPosted: Sat May 13, 2023 1:46 am
by topsail725
Hey everyone, I recently picked up an 8'6 longboard to try and surf the great lakes. I'm from NC originally, but I live up north now and would like to try out Lakes Michigan and Superior to keep surfing in my life. Anyways, after buying this board, I realized the middle back fin port is not a single fin box, but rather all three ports are FCS 1 (I believe, after doing some research). Question to you all--am I stuck with a three fin thruster setup with this board, or are there any FCS 1 fins that go 8-9" that I could put in the middle? If so, please feel free to link some. I'm thinking a 2+1 setup with a middle fin at 9" would be ideal, but couldn't find any out there with FCS 1 ports. Then I can experiment with our without the sides. Thanks!

Re: Suggestions on fin setup 8'6 longboard

PostPosted: Sat May 13, 2023 7:05 am
by waikikikichan
topsail725 wrote:Hey everyone, I recently picked up an 8'6 longboard to try and surf the great lakes. I'm from NC originally, but I live up north now and would like to try out Lakes Michigan and Superior to keep surfing in my life. Anyways, after buying this board, I realized the middle back fin port is not a single fin box, but rather all three ports are FCS 1 (I believe, after doing some research). Question to you all--am I stuck with a three fin thruster setup with this board, or are there any FCS 1 fins that go 8-9" that I could put in the middle? If so, please feel free to link some. I'm thinking a 2+1 setup with a middle fin at 9" would be ideal, but couldn't find any out there with FCS 1 ports. Then I can experiment with our without the sides. Thanks!


Just words for thought, not criticism.

1) If there is a 9" single fin made with the FCS1 two tab design, don't you think it would rip the plugs right out of the fiberglass ? I think
FCS made back in the 90's with a 3 tab center fin that mated to 5-6 plugs.

2) If you do happen to find a suitable two tab center fin, where would it mount on the board. In the same place as on a board equipped with a center box or further back ?

3) How about the other 2+1 set up ? The shortboard world has taken 2+1 as two large side fins and a smaller center trailer fin. They say our long board set up should be called "1+2". That set up would work in your board. I recommend the MR.TX in glass flex.

4) The basic base line set up for single fins, it's usually inch for foot. So if you have a 9 foot board, you can start with a 9 inch fin. They move a 1/2 up or down to adjust, if your fin ends up all the way in the front or back in the box. So your thinking to have a 8'6" board with a 9" fin PLUS adding side fins, seems too much area.

Re: Suggestions on fin setup 8'6 longboard

PostPosted: Sat May 13, 2023 12:03 pm
by Geezer
I had a 9’4” longboard that had a 3 fin thruster setup. Bottom contours were a distinct double concave theough the fins to a V out the tail. Pretty standard thruster contours…….I have no idea how that might have played had I converted the board to a single fin with a fin box installed. Don’t know if the tail was thick enough to support a big fin box or if was too foiled out, don’t kniw if the remaining two fin plug sets were at the right spot on the board for side bites or if they were toed in at the correct angle and cant for a 2+1.

Anyway, personally I would not change the fin setup; board was shaped to have a thruster.

BTW, I an a big fan if the MR fins WKK mentioned. I have them in my 7’6” mini mal and it is pretty loose for a mini mal and it flies.

Re: Suggestions on fin setup 8'6 longboard

PostPosted: Sat May 13, 2023 1:52 pm
by topsail725
Hey guys, I appreciate the replies. I had no idea they shaped longboards to have thruster setups. Here's a couple pictures of the board, and the fin ports. If you guys could let me know my options of different "1+2"s or other setups feel free to let me know. Thanks again for helping me figure this out. All my shortboards have been glassed in fins, and my longboard was a 9'7" Action with a large middle fin box. (the one pictured is the 8'6) So this is new to me.

Re: Suggestions on fin setup 8'6 longboard

PostPosted: Sat May 13, 2023 5:02 pm
by Geezer
Ride it as a twin, twin plus trailer or as a thruster. Thats a pretty nice board; I wouldn’t try to put a single fin box in that, would ride it just like that.

I would rip off that tail pad though but that’s me. ;)

Re: Suggestions on fin setup 8'6 longboard

PostPosted: Sun May 14, 2023 5:58 am
by waikikikichan
Here’s a center fin for two tab plugs. However the biggest they sell is 7.5”.

IMG_7144.jpeg

Re: Suggestions on fin setup 8'6 longboard

PostPosted: Sun May 14, 2023 2:58 pm
by topsail725
Thanks again guys. One last question if you have a minute. If you had this board, and most of the waves you surfed were knee to chest, which fin system would you prefer to put on that board? Sounds like from geezer my options are 1. twin, 2. twin plus trailer or 3. thruster.

Re: Suggestions on fin setup 8'6 longboard

PostPosted: Sun May 14, 2023 8:18 pm
by waikikikichan
topsail725 wrote:Thanks again guys. One last question if you have a minute. If you had this board, and most of the waves you surfed were knee to chest, which fin system would you prefer to put on that board? Sounds like from geezer my options are 1. twin, 2. twin plus trailer or 3. thruster.


1. Twin - The plugs are too far forward to run typical twin fin templates. You won't get much drive and the board will fill pivot-ee.

2. Twin plus trailer - the trailer will help stabilize the rear. But if you don't have a good transition from rail to rail ( or good bottom turn ), then the side fins might feel grab-ee.

3. Thruster - That is the fin set up the board was designed for. But there in lies another dilemma for you, WHICH thruster fin template / size / material should you go with ?

By the way, is that a Greg Griffin or Keola Rapoza shaped T&C surfboard ?

Re: Suggestions on fin setup 8'6 longboard

PostPosted: Mon May 15, 2023 1:31 pm
by topsail725
Yeah, would that MR.TX in glass flex be good as a thruster? It's a Greg Griffin T&C. I'm still not clear, in general, about if a thruster set is all the same size (3 of the same size), or if a thruster set can have a larger back middle fin.

Re: Suggestions on fin setup 8'6 longboard

PostPosted: Tue May 16, 2023 8:48 am
by waikikikichan
Okay how about this.......
#1 Go to your local surf shop.
#2 Ask them for a FCS M-5 glass flex tri-fin set.
( if the shop has only a G-5 tri-fin set, which are Black in color, those will do to since that is what the board probably came stock with )
#3 Check to see if there's a Right, Left and Center fin.
#4 Purchase it.
#5 Install it.
#6 Go Surf.

Re: Suggestions on fin setup 8'6 longboard

PostPosted: Tue May 16, 2023 12:05 pm
by zalle
Probably best to get a 7" center fin and 2 side bites (smaller than average side fins). That's somewhat equivalent to a 9" single fin.

Re: Suggestions on fin setup 8'6 longboard

PostPosted: Tue May 16, 2023 9:55 pm
by waikikikichan
zalle wrote:Probably best to get a 7" center fin and 2 side bites (smaller than average side fins). That's somewhat equivalent to a 9" single fin.

A 7" center fin that fits in a center box with screw nut/plate or a 7" two-tab fin that fit into plugs ?

Re: Suggestions on fin setup 8'6 longboard

PostPosted: Wed May 17, 2023 10:02 pm
by HaoleKook
I just got a new custom-shaped Arakawa, also 8'6" thruster. This board is meant to turn and ride on rail, he said a 2+1 wouldn't pair as well with it, and once I surfed it was 110% in agreement with the fin setup.

My favorite rental board is a 9' thruster. It has loads of stability from the volume and shape, but surfs loose and fun because of the fins.

The OP's board looks like it has the wide point back and a pulled in nose (?), so a performance, turn-oriented board and I don't think the thruster is out of place? (IDK how much the camera angle is affecting that.)

OP, is there a particular reason you want a big center fin?

Here is a link for a single 6" FCS fin, though it's pretty small in area compared to a typical 6" longboard fin:
https://www.surfnvs.com/collections/ape ... -base-apex

Thruster fin boxes were not designed to handle the loads of larger 'longboard' or 'box' fins which is why you don't see much in the 6-7" range. This is according to a conversation I had with the folks at Island Fin Designs.

You can have a board shaper/repair shop change the fin boxes if you really want, but OP's board was likely designed to surf with a thruster and I think OP should try some different thruster setups before doing something outside the norm. That said, there are Box>FCS adapters if you decided to have a longboard box put in, then later decide to surf it as a thruster.

Re: Suggestions on fin setup 8'6 longboard

PostPosted: Thu May 18, 2023 2:54 pm
by topsail725
Thanks everyone for the replies, I am grateful for this forum. You've all helped me understand this much better. I think I'll get a thruster setup and see how it flies. Then adjust from there if need be. Yeah, I just thought since it was a long(ish)board that I would definitely need a large middle fin. But from all of the comments I've realized that's not the case. Thanks again!

Re: Suggestions on fin setup 8'6 longboard

PostPosted: Thu May 18, 2023 9:12 pm
by waikikikichan
Here is a T&C Rapoza from the same era as that Griffin.
IMG_7269.jpeg


IMG_7268.jpeg


IMG_7270.jpeg