Yet another fish fin placement question

I know this topic has been done to death, and everyone’s first instinct (mine included) is “go check the archives”…

Well, I did that, and the general consensus in the archives is, “well, it really depends on the length, width, depth of buttcrack, distance between pins, base/height of keels, etc…”

So, at the risk of being redundant, can someone help me out with a good set of fin placement dimensions?

The stats: The board is a scaled up Lis-style fish, directly from “surfboard design and construction”.

Length is approximately 6’, max width 22", tail width 17", distance between pins 13.5". Depth of buttcrack 6.5" and base of fins are around 8". Fin template will be G&S keels from Rainbow for Lokbox. Bottom is lightly veed with very, very light double concave.

All I really need are a good distance from pins, distance from rail, and toe. Cant comes built in to the keels.

Thanks guys!

I am almost done with a 6’0" fish and I put my fins at 71/2" up from the tail, Toe is 1/4" and I think they are 1 1/4" in from the rail.

Scott

Hi there,

If you’ve been through the archives you will have got a range of opinions on distance from pin, distance from butt crack (Vee in tail), distance from rail, toe-in and cant.

I went through this about 2 weeks ago and in short, you will need to make some of your own decissions about what you want out of the board. The reason is that it depends on whether you are going to be 100% faithful to the original fish design and what types of fins you have… here goes with a heads up.

  1. The original fish design was leading edge of fins no further than 15" from pin, zero toe-in, zero cant… If you want to stay 100% with the original, this is for you. I’ve never riden a board with this fin placement and I’d suggest that it would “track” and not turn all that well.

  2. For a modern fish you have a number of considerations.

a. Toe-in: If you are using single foiled fins (i.e. flat on the inside panel of the fin) you are looking at a toe-in of about 1/4"… I have a twinny that has toe-in of this. If you are using double foiled fins, go for less toe-in… say 1/8" to 1/16". More toe-in gives you a looser feel in the board. It depends on what you want.

b. cant: If you’re using turbo fins (fins with a curve through the profile) you are looking at cant of around 10 degrees. (I know lokbox do turbo fins, thats why I’ve mentioned it). If you are using normal fins, 3 - 4 degrees cant is normal… more cant gives you more lift inthe tail and therefore looser feel aswell. Again, depends what you are looking for in the board.

c. Distance of trailing edge from stringer: This really depends on how wide the tail of your fish is… I went for 5 1/2" from stringer for the trailing edge of the fin which was about 1 1/2" from the rail.

d. Distance from Pin: For your board and fins, I wouldn’t suggest going too much more than 15" from leading edge of fin to pin… so for an 8" base, maybe 7" from pin for the trailing edge of the fin (1/2" from butt crack) For a 6 1/2" butt crack, some guys on here have even gone for level with the butt crack… that would still work.

*** My overall suggestion would be speak to people who use the fins you intend to use on similar dimensioned boards and see what they suggest… this is where I got most help for my decissions as I found a guy that had used the fins I’m using on a few boards and he had already tried a few different options both good and bad. Just ask your supplier if you can’t find someone on here… the good thing about fish fins is that if your supplier is selling lots of em it’s a fair chance that they are all going on fish boards.

FYI, the fin placement for my fish are:

  • Twin fin: Finfektion D2 fins (8" base, 5 1/4" depth) - double foiled

  • Trailing edge 6 1/2" up from pin (1 1/2" up from butt crack)

  • Trailing edge 5 1/2" in from stringer

  • Toe-in 1/8" (i.e. Leading edge 5 3/8" in from stringer)

  • Cant 4 degrees

Check my website for pics.

-Cam

www.geocities.com/thefishexperiment

J.

Foamdust sent me these specs right off his custom Steve Lis…

Quote:

Here are the specs on the fin setting on my Lis fish.

Swallow- 10 1/2" wide; 5" deep

Fins- 7 1/2" base, 5" height; set 6 1/2" from tail; back of fin set 1 3/4" from rail.

Toe in- 1/4" difference between front of fin and rear of fin. Front of fin 5" from stringer, rear of fin 5 1/4" from

stringer.

Cant- 0 degrees

Good Luck…

I got two in the oven (final lam + glassing) and two more being rocker glued up for shaping…

I’ll let you know how my rocker glue up experiments goes… I’m unwrapping them tonight!

I just finished a 6’0" fish as well. After reading through the archives and talking to a dedicated kneelo I know who’s been kneeling & standing on fish for 25 years, I put the fins at a very traditional: trailing edge even with the deepest part of the crack and 1.25" in from the rail. There is 1/8" toe-in on each, no cant. They are glassed-on wood keels, 8.5" long by 4.5" deep, single foiled. They feel about right, as they scoot past sections like I have a passing gear.

Yep,

I would say the same…7-1/2 - 8" from pins(my brom was 8"…) , 1-1/4- 1-1/2" from rail, and toed in a 1/4" (brom 1/4" toe as well…) . My first ones were parallel…and went fine/fast . The ones after with 1/4" toe are looser but with the drive and speed as well…have fun…