Does rocker increase per board length?

General Discussion
21

I decided to take another look at my rocker measurement which I did on my front lawn using mostly just intuition but no exact procedure.  This gave 5 5/8"N and I said 2 1/4"T but I think I misread my tape - it was 2 3/8"T.  No big deal.

So I went down into my basement - I first levelled my shaping stand, then put the board and levelled it and then I noticed something: a dot on the stringer.  The dot is leftover from

when Ryan or one of his shapers shaped the board.  The board is 86" long straightline and the dot is 44" straightline from the tail.  So it’s 1" forwards of center (43").  Now at this

point, the board is 18 3/4" wide, and it’s also this wide approximately for another 1" or so behind the 44" point and it starts to fall of in width forwards of this point.  This IS a

good point to use for the “0-rocker” point.  It gives exactly the same as my front-lawn measurement: 5 5/8"N and 2 3/8"T (sorry about that 1/8" misread the other day).

 

I do not yet know if Ryan used this to measure his rocker from but BOY it sure seems like a good spot since you would have a nice, permanent reference point to measure it

from.  So we can say that the board’s unofficial 0 of rocker occurs at about that dot (44" from the tail).  Makes sense for a performance, a step-up, or a true gun since

we do not expect as much carving, need the paddle, expect more lift from trapped water, etc…  Typical gun shape, that’s all.  Some shortboards have their widest there too, but

most are a bit back more towards the center or even a little behind the center.  Whatever.  So my lawn-measurement was correct since the board does NOT absolutely have

to be level - as long as the rocker-stick is level with the BOARD (it’s not really the lawn that matters so much).  But while I was levelling everything I realized that it’s really

mostly WHERE fore or aft we put the rocker-stick that matters - this makes our life easy!  So my apologies - his board is 18 3/4" wide, not 18 1/2" as I said before.  It says

7’2" x 18 3/4" x 2 1/2" on the stringer.  Here’s a pic - Enjoy.  By the way, the shape of this Sakal is good for BOTH tube-riding and carving in the tube - a good all-round

hollow-wave board.  It has it’s wide-point near the center making it responsive without a struggle for “back-foot” surfers.  If I only had a 2 5/8" thick version, but hey, hurricane

season is still alive, I’ll take it out there for some fun 10-footers!

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22

I do not know any better way to figure this out besides riding lots of boards and measuring them and keeping copious notes. By doing so you can begin to get into the kind of understanding a good shaper has. There is no such thing as right rocker or consistent from this to that. You have to get a numerical grip on what you like to ride by attaching measurements to feel. This is complexified by width, bottom contours, fins and their placement etc as well as by wave conditions but you hafta start somewhere - no one can tell you anything except what is most common for a certain type/size of board.

If the question is: if I make the EXACT same bord in a shorter/longer length will the rocker increse/decrese proportionally? Is that really a question? If you change the length but don’t change the rocker it is no longer the same board.

23

The rocker in the middle 1/3 of the board is the same for all my boards (shortboards, not mals). I also hit pretty much the same numbers at tail and tip for boards from 5’6" to 7". This means that the curve joining the tip to the middle 1/3 intake gets drawn out for longer boards and compressed for shorter boards. Similarly for the curve from the middle 1/3 outtake to the tail.