How do I alter rocker and wide point of a round tail for a swallow tail?

General Discussion
1

I’ve got a round tail design that I’m really happy with. I’ve been refining it for a few years and have ended up with a high performance board that goes well in 2’ to 8’.

I’ve been playing with swallow designs. Because of the way I like swallow to look (outline curve into the swallow), I keep coming back to the round tail outline. Cut 2" off the tail, whack in a swallow and the plane shape looks good. So a 6" round tail outline becomes a 5’10" swallow.

But cutting 2" off the tail means that the wide point moves back and the rocker low point, too.  It also means that I lose 1/2" of tail rocker and the fins move forward. In theory the board should end up fast and loose, but I don’t want it to be squirrely.

Is there a better way to modify a shape to carry a swallow?

 

2

…seems that you want a different area in the tail…I mean, if not why to cut 2" from tail?

You can accommodate a swallow tail without shortening; you should start having different types of tail curves (outlines) then check the outline at 1 ft and mark the new line or in some cases, you should check the outline at 24".

 

Cut a 6 board only from tail DO NOT convert it into a 5 10; it s not scaled; you transform that shape in a different animal, more prone to small surfing.

 

3

  Yeah, cutting that 2" off would affect the outlines performance much more than changing from rounded pin to a swallow.

  You move the widepoint back 2".

  You shorten the planing surface at your rear foot.

  You thicken the profile and the rails at the rear foot.

  You lose a huge percentage of paddle power and wave catching.  Now you're atop the board at a different spot than the original board's sweetspot.

  You gain some side to side quickness while losing lots of projection and carry out of turns.

  And you'd need to adjust the fin position.

  Using the swallow also decreases the planing surface.

4

That’s great input! Thanks.

Firstly, if I use the same outline I need to cut a bit off otherwise the swallows end up “underneath” the curve as it wraps in to the tail (yes, I know, a picture… on the other computer). Create a new outline or at least swing the template out at the tail. Check

The thickness. Yes it gets stuffed up and short term corrections end up in a S-deck. Redesign the top rocker. Check

Bottom rocker. Low point moved back and tail kick compromised if board shortened. Don’t cut off tail. Check

These are the two bits of gold for me:

Alright. I’m into a from scratch design. A swallow for 2-4’ cleanish waves.