surfboard volume

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tony's picture
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surfboard volume

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I noticed an ad for a windsurfing board that stated the volume of that board in litres. Both Al merrick and Rusty Preisendorfer have said that volume is a very important component of a surfboard. Different volumes for different size surfers and their abilities and the size and types of waves they ride and their likes and dislikes. Unless calculus is applied or the board is designed by CAD, it would be very difficult to determine the volume. It might be a good measurement to add to the normal width, tail, nose and thickness numbers but how the heck would you calculate it? 

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Re: [tony] surfboard volume

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This has been asked of Mike Daniels on the Coil thread on how the guys at Coil figure it out for their boards his response has been "software for your shaping machine, knowing the density of the foam and weighing the blank, submersion tanks all are valid ways of figuring out volume"

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Re: [tony] surfboard volume

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I was gonna, say turn it to 11.

Or, you might want to read up on Archimedes, and his bath tub.....

MikeD, to the microphone!

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Re: [tony] surfboard volume

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Learned hull design from building boats from drawings so bend your head accordingly.

A site to introduce you to several concepts:

http://pages.swcp.com/usvmyg/design/design.htm

Look at the board design end on.

Break the length of the board down into 10 stations.

Figure the area of each station.

Use the chart about 3/4 of the way down the page to calculate the displacement.

Once you get comfortable with calculating volume you have to start looking at where the displacement is located in the board - front/middle/back - some combination thereof for displacement.

Riding styles, board design theologies, er, trends that is, materials, production approaches, etc.. decides how much and where that volume should be distributed.

If you're looking for someone to tell you where the volume of the board should be distributed, good luck.

Oh, 1 cubic foot of volume of salt water displaces ~ 64lbs

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Re: [tony] surfboard volume

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I'm with obproud, the simplest and most accurate way is like Archimedes did it. Though for eas of operation, I might go with an empty trash can on a scale to catch the overflow, then use http://www.onlineconversion.com/waterweight.htm to do your conversiions - saves a lot of measuring.


An equivalent- go to a pool, with your weight-lifting weights and the board. Check how much weight it takes to completely submerge the board, run the above link and you get a readout in volume.


I'll note that the simple volume only tells you how much the board will float. As has been mentioned, where that volume oughtta be is a far more complex question.


hope that's of use


doc...

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Re: [tony] surfboard volume

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Yeah, we talk about volume a lot on the ride reports thread. Because quantifying it is as important as quantifying length or width.


Dave Verral (feraldave on here) of Diverse in Australia, and Kirk Brasington and I of Coil in USA were the first to include volume #s written on the board.


It will be a common thing in the future.

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Re: [tony] surfboard volume

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There is a great simple formula in the archives.  I forget who posted it and I apologise for using it without their name attached (many thanks - I've found it very useful over the years, and pretty accurate). Here it is:

approx vol = 1/2L x W x thick + (10x every inch over 6')  all measures in decimal inches

you get a big number (cubic inches)

divide by 61 to get liters

works best for shortboards

[edit to correct formula]

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Re: [tony] surfboard volume

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At the Sacred Craft last October in Del Mar there was a guy who did a workshop session on volume that was excellent. His first name was Whitney, sorry but I can't remember his last name. Hope that he will see this thread and chime in! I looked for him last weekend in Ventura but didn't see him. 

He has figured out a relatively simple way to measure overall surfboard volume. I'm not great with math, so I don't remember all the details. It basically involves using a large rectangular tank Whitney has designed, to measure the water displaced by the board in liters. Then you convert the rider's weight to kilos and compare the two to get a percentage. (Metric makes it congruent.)

He stressed that the right board volume PERCENTAGE for an individual surfer isn't just based on weight but also on things like upper-body strength, etc. It really clued me in! It explains why, as an over-50 female surfer with some rotator cuff issues, I can't simply go by my weight when ordering a board! (I wonder if some women are so used to understating their age and weight that they end up with boards they can't catch many waves on, LOL!)

Whitney, if you're reading this, I'm not trying to give away your secrets or anything - I hope that people who read this will seek out your expertise.  Val

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Re: [Art4Peace] surfboard volume

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"I can't simply go by my weight when ordering a board!"


 


That is worth posting front and center on page one.  Any formula or size chart I've seen was incorrect but for the sheep who didn't know better.


Ignore them!  Try more boards!  Decide for yourself what works for YOU, then tell them what YOU want!