Adding side fins to a modern California pin single.

I have a new this year 7 x 21" round pin shaped by M Baron that I’d like to add side plugs to.

Any advice on side fins and a rear center fin that can drop into the existing box. (Right now I have an 8" Greenough that I like a lot.)

This board is for over head and windy winter conditions in Maine/NH point surf.


Question is, why?

What are you trying to achieve with the side bites, or even just using the board with two 6" side fins, no center.

Tail width of most singles are sub 13.5, so a tight cluster and general stiffness with fins affecting one another.

But without knowing why, and dimensions, can’t say really.

I’m curious to see how it would ride as a 2 +1 set up and I’d like to have the option. I was thinking FCS sides would’nt be too difficult.

The tail is 13" and the nose is a hair shy of 13" and the wide point is just forward of center. I really like the outline of this board, it paddles great and thought the tri fin might give me more off the bottom.

Since it’s designed for head high surf ideally, I’d pass on FCS system…too weak for fins over 5", but fine for tiny side bites.

If you plan on side fins bigger than 4.5", go with another system…Futures, Lokbox, FinsUnlimited.

Move the trailing edge of the side fins up about 15.5", since WP is forwards on a longer board.

If sides are 4.5, trailier can be 6".

Re:Your board----It does’t sound as if it’s broke, I don’t think you should try to “fix” it.

You bought a single fin . Therefore ride it ! As a single fin…it will do you good !

If you want a thruster, buy a thruster.

Chalk and cheese. Chalk and cheese…you get what I’m saying ?


One more vote for keeping it a single. There’s a whole lot more to fins than just how many. Your board has rails, hull contours, rocker, and planshape - and the shaper designed all those variables to work with a single fin.

If you want more drive, try a Greenough 6 ‘paddle fin’. Its got huge surface area to push you along but also stays loose. Interacting with the typical rail shapes of single fin boards, this fin allows you to fade deep and whip out like a 2+1, and then accelerates while in trim like a big pivot fin.

All it needed was more wave. Just got out of the water here in NH. We’ve got a large swell hitting and the single felt great.

I will try the paddle fin. When I first looked at it I was scared off by the funky shape. Thanks for all the input. MDM

Hey MDM,

There’s a lot more info need than just board length, width and where it was made to decide what kind of fin or fin set-ups will serve it best in a given set of conditions. Some boards surf better with a single fin and that’s all there is to it. Others will accept a variety of fin combinations and surf a good varity of surf conditions as well. Other boards are worthless without three fins. Without details (photos are great)it’s impossible to say if your board will be served by rail fins. Send me a personal message if you like or we can address it on this thread if you choose to persue the issue.

Mahalo, Rich