# Board sizing ratios.

Had it saved and lost it. Now can’t find it.

Anybody have the location of a thread concerning the how to of changing a board’s size and still keeping the measurements relations constant?

Might have been GL that had some simple formulas.

Just scale it up, or stretch it, those are the two extremes, they both work, and anywhere in between will too.

Thanks TB but this was a thread with some simple math for say, making a board longer while still keeping the width relatively the same.

Had it saved and lost when converting info to new computer.

It is somewhere in the archives. Like TomBloke says, there are at least two methods. One being direct proportioning, the other involving stretching the length. If the boards are fairly close, direct proportioning works. If you try to scale a 6’ X 18" shortboard to a 9’ longboard however, direct proportioning results in a very wide board…

72/18 = 108/X (cross multiply and divide…)

18 X 108 = 1944.

Divide 1944 by 72 = 27.

27" is pretty wide for a 9’ longboard.

Here is Greg’s formula if you want to stretch it instead of direct scaling…

Surfboard scaling

Use the traditional 22.5 inch for the top of the scale (9 footer) and use 18 for the bottom (the 6 footer). Take the 4.5 inches between and divide them by the 36 inches between 6 foot and 9 foot. You come out with 0.125” which is 1/8 of an inch. For every inch of length you adjust by 1/8 of an inch width.

(EDIT: original ratios got scrambled in post)

That was it. Thanks.