twin fin placement?

hi guys,

I read a lot about twin fin placement in this forum, but it seems to depend a lot on the shape and the board length…so I have to ask you.

It is my first twinnie and I don’t want to do a big mistake.



this will be my everyday board, I’m doing a little bit of an experiment, because a wide diamond tail is not common with twin fins, but i will check if it works…

what do you think would be a good fin placement?

I thought of 9" of the tail and a little angle of 4 or 5 degrees. But where should I place them off the rail? 1" or 1 1/2" ?

In combination with the fins, I expect a fast and loose board with a tight turning arc (for twin fins)

BTW, I will use the rasta keel fins:


I think you guys might like the board, so I’ll post some pictures of my first twin fin…

thanks a lot!


9" from the tail is pretty far up for keels. I like them further forward than most, but i keep them at 7''. Most people put them around 5 1/2 - 6 1/2'' from the tail.

That looks very similar to a board I just made. 5'8 3/8" is pretty specific. I got a 6'0 1/2" custom one time and thought I was a bit particular:)

Good timing on your question, I'm in the process on #2 which is going to be a twin.

Sounds like you're talking about a twin keel rather than a twin fin.
( Sorry to be pedantic but just so we're all on the same page ....)
Since you're using those Rasta keels , here's a snippet about a Van Straalen I've examined , cut n pasted from another thread, might help.
Posted: January 5, 2010 - 3:51pm | #4 (permalink) | Back to Top

Just two hrs. ago I  was scoping out one of these

click here for dims

It’s got  Futures  Rasta/Sea Shepherd keels set at   7 ‘’ from the
tail tip  , trailing edges  1 3/8  to 1 1/2 ‘’  from the rail ( couldn’t
tell exactly ) , toe’d   1/4 ‘’   -   I 'd estimate the cant to be  6
deg.,  more or less.

 Any way a bit of info for ya.

why you need the round nose?

MR style side fins go better than rasta ones....

Just My opinion bro, i Love new schooll fishes

hello guys,

thanks for your replies. I’ll answer to your questions…


Mark Richards says 10" and my theory was, that “forward -> more loose”. That’s the reason why I put them a little bit more backwards (from 10 to 9") and because of the fact, the rasta keels have a lot of area, what could make them stiff. I was mixing up some things…sorry…

We’re talking about keel fins, you’re right…as I said before, my first twin.


The 5/8" are because of the over curve line and the rocker. Actually it’s a 5’ 8".


You’re right. Thank you for the measurements!


5’8" is a very short version of a fish for me, as I wrote my first twin keel fish. And I like a little bit extra foam in the nose for chatching waves.


I’m still changing some things on the board as I found this picture, so I made the tail wider. Shaping starts next week :slight_smile:

This tail is still a bit wider than my one, but pretty similar though.

I think 7" or 7 1/2 " of the tail, maybe?

It’s good that I asked you before shaping, I was just searching with keywords like “twin fin placement”, but didn’t think about the fins, that I’ll use…

I didn't see the part with the rasta keel.  Hugo I think we are on the same page just about.


I just shaped a 5'8 round nose fish and am having some rasta keels made up in bamboo / probox setup. I'm going to try and glass over the weekend. I will post up some pictures.


The 5'10 that I made which looks like your cad outline is done as a quad which works very well. It's a good blend of drive and performance.