"Today everyone is focused on one aspect of board design…volume.
Let’s put that aside.
There are so many other elements that contribute to how your board performs.
They are all somewhat equal as to how important they are.
Rocker is perhaps the most important.
What is rocker? It is the curve of the bottom of your board.
There is the stringer line, center rocker. Rail curve, the rail line. And to a certain degree the various changes in rocker through the middle of the board depending on whether or not there are concaves or convex curves running from nose to tail, or in between.
Rocker is designed to make a board fit a particular type of wave.
Hollow, mushy, short, lined up, etc.
Rocker is designed to determine the arc you want, need, or like to make on your turns.
Flat rocker planes. Has longer arcs. Fast down the line.
Difficult to bring up the face. Great for softer, lined up waves.
More rocker doesn’t plane as efficiently. It has tighter arcs.
More tail rocker fits hollower waves.
For larger waves that are difficult to catch but jack up as they feel the bottom; I like a lower entry rocker with more tail rocker. The lower entry will help you with paddle speed, catching the wave a little earlier than a board with lots of nose rocker.
A board with “high” rocker on both ends is good for very hollow waves. The “fits” the curve of the wave.
When people ask me “what if I put more rocker in the tail?”
With almost every element of design, I tell the person, “imagine what you are asking and take it to an extreme.”
One aspect of a shapers job is to find some degree of balance and flow.
Rapid breaks in rocker create drag. Smooth lines on the board flow better but tend to be a little harder to turn, or “break your line.”
Numbers in surfboards, are important.
There is an artistic approach. Not as dependent on numbers.
That’s cool. Everyone marches to a different drummer.
Well over four decades ago I realized that the more measurements taken, the greater likelihood of recreating a good design, and improving on it.
With CAD design software, numbers are virtually infinite.
With boards like a fish, usually the front end is low.
The back end has average rocker.
My numbers aren’t gospel. Just to give you an idea.
A 5’10 Fishy thing has 3.75 inches while the tail has 1.9 inches.
Wade Carmichaels boards are quite curvy.
He’s bigger, heavier surfer and likes to do very hard, vertical turns. Put simply.
6’0 nose rocker is 5” and the tail is 2.3”
Caio Ibelli has the most rocker I’ve used.
Coupled with his thumbtails, that enables him to do very tight yet fluid turns.
5’9 - 5" and 2.4. Boards for bigger waves. Boards for hollower waves."
- Rusty Preisendorfer