The above pic should have been labelled:
Ryan Sakal 7’2" x 18.5" x 2.5" x 5 5/8"N x 2 1/4"T simple rocker measurement.
And I meant to say, “See duh bro Barry Snyder’s comments for more on rocker measurement”.
My editing didn’t go well, sorry.
Keep in mind that you really just need to pick a reference point and stick to it. If using the computer, try to use the computer’s exact point of 0 rocker. Sometimes
we don’t have this luxury - perhaps the blank isn’t even shaped enough yet. Just stick with a point. But there is a point where the board stops going out and starts
going back in. In my pic of the board on it’s deck, it’s the highest point on the board. We just have to find it somehow - in my case, my rocker-stick has a centerline
that is pretty much the center of gravity so we can play a game of see-saw as someone else mentioned in this thread but be careful that your board is the same
mass on each side of centerline - not always a good assumption - so what to do? Don’t use a KD Spruce or Douglas Fir stick - get one that’s hyper-moderne somehow.
How? I don’t know - See someone like Barry Snyder until I come up with a better stick! Maybe use a graphite stick or plastic or aluminum or some other metal. Woods
are not as reliably uniform in density. We need uniformity in density or we need a good eye to see the point of 0 rocker or both! I guess you can use your surfboard
to find the center of gravity just by balancing it while measuring the rocker and then mark the board for future use! Or put the piece of wood on some thin edge and mark it
before trying it with your board. So wood is ok - just be careful to find the center-of-gravity sooner OR later. But be wary that wood is kind of a dynamic beast - it’s
moisture content could change in a funny non-uniform way or something. Just beware of these things. Your eye is almost as good as the center-of gravity. Try
to use a real nice flat table under your board - this is not always easy for people - you may have to build it! The 0 of rocker is not really a unique point - if you put
your board on it’s belly it may not lie right on the 0 of rocker. Likewise on it’s back, if it’s on an incline, you will get a different 0 of rocker depending on the incline. So
it’s kind of complicated. Just relax and pick a point that looks pretty good and stick with it. Now your nose and tail rockers are forever in a give and take - whatever
the nose gives, the tail takes and vice-versa. But you shouldn’t really care because it’s the same board either way! So we could have a board sitting on it’s nose and it
would have 5" of tail rocker but that would be ok since the 0 of rocker is on the board’s nose (not near the center) - after all, it’s the same f-in’ board. So relax and pick your best point, and be careful of rocker flow - is this a hot-dog board, a small-wave board, and do you care which?