Aloha surffoils

We have been through this discussion in detail on another thread a year or so ago. Some proposed the same system you have here. But it has many shortcomings. Let me see if I can address the problems that exist in your proposed system.

#1 How much nose rocker is in the board you drew out?

It appears to be Zero. Tail rocker? Seems to be Zero also.

Hmmmm… kind of hard to discuss, reference and compare to other boards as they will always measure Zero regardless of the board. I guess we could all begin by saying… “my board has 8’5” of Draft. And then we could have some formula to translate that into 6" of nose rocker and 2.5" of tail rocker. Or… "Hey surfer Joe, how much rocker is in the nose of your new board?. Joe replies, “Zero, but I am thinking of getting a little more in my next board, so I think I am going to boost it up a bit more to Zero next time”.

#2 How does one (simply) measure the bottom of a board along the stringer from the deck side? Drill holes through the board? [:)] This is about real world shaping use. Not speculative drawing.

#3 The widely varying thicknesses of the tips of noses (beaks) and tails will skew your measurement unless you use a complicated method of isolating the bottom from the deck thickness.

#4 Since most everyone uses a straight edge perpendicular to the Tangent at the center of the boards length, using a different system will leave one without easily comparable numbers to others.

#5 And maybe most importantly. We actually ride on that outside surface we are measuring. Therefore, the intuitive connection between the rocker numbers and what we feel just makes more sense. IE, “the board I had with 6” of nose rocker pearled too easily so I boosted it up to 6.5" on my new board".

#6 We also shape on the outside of the curve. So once again the intuitive familiarity of shaping and measuring the same surface is much better then measuring inverted surface and shaping the extoverted surface. Additionally, the shaped measurements are mostly in increasingly larger numbers as blanks typically come flatter then needed. Working with inside measurements would require thinking in reverse with decreasing numbers. And it would also be very difficult and disruptive (assuming you did come up with a system other then drilling holes through the board) to quickly check rocker measurements continually which is often necessary throughout the shaping process.

#7 The ONE point all surfers can agree on is the center of the board and its Tangent to form a consistent base line. It is always right there in the same place on every board, regardless of length, thickness or shape. And it only requires ONE point, not two, to create the base line.

I think the reason people struggle with this is that they really don’t understand how simple it is to create the baseline by simply pressing on a straight stick at the center point. Level doesn’t matter. Balance doesn’t matter. Racks don’t matter. Length of stick doesn’t matter. Even gravity doesn’t matter. You could be in outer space and it would still work perfectly. Simply press on center with one hand, measure quickly and efficiently with the other… End of story.

#8 My system is simple, fast and accurate. Try it in real life and you will see.

Hope this helps, I have been enjoying our discussions.

Quote:

Hi elewis, Im fairly sure that if you were going to measure any curve, it would be more accurate if done from the inside of the curve. Like they do with airfoil curves, circles etc..
The only 2 points all surfers can agree on are the nose and the tail,( where the rocker starts at each end)

So put your board fins up, with those 2 points of the (BLUE) curve, level on a flat (RED) surface.

Pick you incremnents and whether you wish to measure in mm inches and measure UP from the flat line.

Its a replicable system based on easily identifiable points.

They dont measure wing shape from the outside either.

Its all done from the inside of the shape with a single base line for reference.

In practise, youd have to make something that took into account a surfboards real shape of course,but using a single solid level base line is so simple and easily scaleable.

Regards, SF.