Surfing Waves

Always dangerous to go down, but, here we go...

I was thinking of pairing a smaller center fin (not a trailer fin like on super twin setups) with my regular center fins on my shortboard. My question is, has anybody tried this? And at what ratio does the looseness start to get extreme?

Here's my idea, i'm using captain fins: center fin height, 4.55", base 4.5," area 15.48"

and my smaller center fin, which is more of a grom size but the same template: height 4.09", base 4.03" area 12.22"

For point of reference, I weigh about 165lbs in a wet 5/4/3, and surf a 6' flyer f. From the era when ci made great boards.

I'm curious as to what is the thinking behind your thought to choose those fins.
A lot depends on how you wish to push the board in your turns and whether you would incorporate any tail waft as part of how you do it.
As to where the ratio of looseness begins well that depends on your control.
Get out with as many fins as you can beg or borrow and just see what works for you

Well, my rationale is I want a little more down the line speed from less drag, but the board isn't really designed as a twin fin shortboard as twinnies usually have vee out the back. The waves here on the east coast don't have a lot of power, so I thought the adjustment might make the board a bit faster on the smaller days. Would that kind of setup allow me to accomplish that?

And yes, fins are pricey. Begging and borrowing are the way to go.

Just go to the local surf shop that has the FCS Test Drive. You can borrow the fins for free ( you pay if you damage or lose them ). I my opinion, you're not going to gain any more speed by using a smaller center fin. That's usually done to make the board looser. I do that when the waves are quick and dumpy.
You said the waves there don't have much power, so you really need to stay in the pocket or up on the higher half of the wave. You can't go any faster than what the wave gives you.

Pretty sound advice. It all goes back to the old adage that it's rarely the board/fins which make a surfer better, rather the surfer themselves.

Having said that, I think that the fcs system, as well as the fcsII, is poorly designed. Futures all the way for me.