Fish outline: how straight to make the rails?

I’ve made 3 fish so far (all about 21.5" wide, 5’4" tall) and I love them all. Their outlines behind the wide point have a bit of curve to them. Nothing too dramatic but noticably more rounded than what I think I’ve seen in traditional fish.

The one thing I’ve noticed in my current fish is that I can push the tail harder in turns than I would expect to be able to do on a twinny. I was wondering if that might have something to do with the rounded outline. I watch video of some of the best fish surfers and they don’t seem like they’re pivot off the tail much at all. They roll onto a rail and do radical slashing direction changes with the entire rail. I’m sure a lot of this has to do with my surfing (I’m not a world class surfer by any means).

But I’m also wondering if my more rounded outlines make my boards conducive to turns similar to performance thrusters. If I straighten out the rails on my next fish do you think I would get a greater ability for less-pivoty, slashing direction changes?

Honest - I’m not trying to be a wiseguy.  Some guys are going beyond straight and utilizing an inverse curve on their ‘sidecut’ fishes.  There aren’t really any specific rules but an outline like this will likely result in a stiffer ride without some other sort of design modification like rocker boost, flex panel, etc.

Do your twinnies have the split tail design feature?

 

 

Without detailled information, even guessing is difficult, but assumed all board dimensions are equal, esp. Outline and tail rocker and fin setup, I would Think that the rail shape in the tail is more responsable for the different feel, than outline…

Well, if they don’t have a split tail then they are not fishes.

Yes. Have the split tail just not quite as deep as the ones pictured.

Interesting… I’m open to more extreme features. The first boards I built were more exagerated so I had a better understanding on what those features did.

Off the top of my head…

5’ 4"

Width: 21.5" slightly front of middle

Tail block width (tip to tip): 11 1/8"

Tail width: 17"

Split tail: 4" deep

Thickness: 2" (i think)

Large keels, 2 degree cant, 1/4" tow, set 6" from tail

Moderately-full 80/20 tucked rails

Rocker dims of the 5’10" blank I used: (nose to tail) 3 15/16,1 5/32, 1 1/16, 2 1/16

Substantial single to double concave (might have something to do with “moderny” way it surfs)

The original Steve Lis template came up in San Diego conditions and were surfed by guys who came up in traditional longboards and where they were driving long arcing lines.    Straight rail is all-drive.    If you want to do more active turning then that’s where some curve comes in.   

Some fish riders really like the Zippi variant where there’s more curve.  It really depends on what kinds of lines you want to draw.   

This helps. Thanks!

“The one thing I’ve noticed in my current fish is that I can push the tail harder in turns than I would expect to be able to do on a twinny.”

Yes Sammy.  Agreed.  Based on my misinterpretation of what is quoted above, I thought maybe he was comparing his fish’s performance to some other type of twinny - possibly split tail, possibly not(?)

I’ve also seen lately all sorts of ‘new’ names for designs that don’t fit my old school/hard headed definitions.  “Fish” likely being the most used - on various short wide designs with and without split tails and/or twin fins.

 

…hello; go to “thee modern fish thread” or like that, to resolve most of your answers about a new fish.