a volume equation

so ive got some spare time. remember torn meniscus? vacation? anyway, so im cruisin sway’s and find an interesting thread about the importance of volume/weight versus only L/W/thick but i couldnt find any equations.

now im no mathe-magician, but with my spare hours, i started playing the numbers. i came up with a few equations that had me cutting the board into triangles and parallelograms and the like, but they just werent applicable in the real word. so i opted for a more simple equation and tried to minimize the rate of error.

here is my formula:

1/2L x W x Thick. + (10x every inch over 6’)

This was normed on the ‘generic shortboard’ series on APS. it remains fairly consistent when playing with rounder shapes, however the more round a board gets, the less accurate it is. Having said that, i never went more than 1.25 liters off when working with rounder boards from 6’0 to 9’6". Using the shortboards only, it remained quite accurate. here are my results.

Generic Short 6’2

37 x 2.375 x 18.5 + (20) = 1645.69in or 26.97liters. APS has this as 27.26 liters

Generic 6’8

40 x 2.5 x 19 + (80) = 1980in or 32.45liters. APS has this as 32.27liters

Generic 7’6

45 x 2.75 x 19 + (180) = 2840.62in or 46.55liters. APS has this as 47.57

Generic 9’0

54 x 3 x 22.75 + (360) = 4045.5in or 66.29liters. APS has this as 66.43

OK, for those of you still interested, the conversion from cubic inches to cubic decimeters (liters) is 1 : 61.02. you can use an online converter or just remember and use it on the calculator on your cell phone.

I hope this can go down as my first, and still only, significant contribution to this wonderful site.

jz


            

Dude, that’s simply-brilliant.

Very E=mc2-esque.

Quote:

so ive got some spare time. remember torn meniscus? vacation? anyway, so im cruisin sway’s and find an interesting thread about the importance of volume/weight versus only L/W/thick but i couldnt find any equations.

Equations…bleh:

http://www.swaylocks.com/forum/gforum.cgi?post=282031;search_string=volume%2Fweight;#282031

Some way to compute volume.

cannot anyone appreciate math?

i think this is going to be greatly useful when looking at boards off the rack. as a 5’8 200lb fairly conditioned east coast usa surfer riding slop most of the warm season, volume is HUGE!!!

(1/2L x W x thick) + (10 per inch over 6’)!!!

I love math. But I’m not sure about the usefulness of a volume measure by itself. The density of the foam also has to be taken into consideration. And I think volume is more important when you buy a blank to shape, so you know what you’re starting with. The funny thing is, one of the most primitive, but most accurate ways to measure the volume of a blank is to submerge it in a tank of full water, catch the water that flows over the top, and measure the volume of the water that the blank, or board displaced.

And when you get right down to it, everyone picks up the board, feels the heft of it, looks at the curves, and makes a subjective decision about how it will fit for him or her. “Oh, man. This looks like it will fly! Probably float me pretty good. How much?”

But good work on the math. I layed awake one night and came up with a formula for converting Celsius to Fahrenheit & vise versa. Celsius times 1.8 plus 32 = F.

or Fahrenheit minus 32 divided by 1.8 = Celsius. Useful in limited situations. But I’ll still go outside and say things like, “Wow it’s hot today.” That about covers it.

Doug

After the exams I can write you a numerical algorithm (just the algorithm not a program) to calculate the volume if you want me to.

But that will be after 10th of februari.

It is impossible to calculate the volume in an analytic way.

very useful - thanks

I just fiund out that I’m riding volume wise exactly what feral Dave said his team riders are capable of dealing with (ie vol = weight in kg x .36)!

Time to ride a higher volume board - I’ve got mathematical proof.