1/2 length x width x thickness + 10 for every inch over 6'
Divided by 60.02 = L volume
It's not exact and doesn't account for certain variances in design but I've done the equation for dozens of boards I have, was looking at getting, or was just testing the math out on and it's a pretty damn good estimate.
Results 11 to 20 of 24
Thread: FOAM - Guild Factor
Oct 24, 2013, 10:36 AM #11
Nov 6, 2013, 04:14 PM #12
but back to the topic at hand, i'm surprised no one on here has commented on the words of wisdom from whitney guild himself clarifying the subject. has anyone played w/ it at all? it was interesting to see how little my GF varied (.37-.39, depending on board), compared to the volumes i ride & feel comfortable on.
Nov 6, 2013, 04:34 PM #13
- Join Date
- Jan 2009
- milton delaware
remove fins, stand box on end, fill box up so the water level is somewhere in the middle of the increments, slide board underwater so it is barely submerged, see how many liter increments the water goes up. it would be perfectly accurate, and was invented by Archemedes oh about 1500 years ago.
Nov 6, 2013, 05:26 PM #14
i've found the GF to come in handy.
i'm 6'4" 220lbs so not your average shortboarder.
I rode a ...Lost Round Nose Fish for years and loved it. it was
6’4 21.5 2.75
GF = .43
I wanted something with more performance on the bigger days so i talked with Matt Biolos at a shaper's night last fall and he suggested a V2 Stub
6’4 21.00 2.75
GF = .42
i love this board but not on < waist high and/or mushy waves.
so i played around with the GF to find a new shortboard for smaller days.
i went with a ...Lost bottomfeeder. i wanted to make sure that this board not only had more volume but would allow me to shortboard when i used to have to longboard. it is a wave catching machine.
6’4◊1 23.50 2.88
GF = .49
i was able find a board to ride on smaller days that would make me stoked. (i rode it all weekend)
if you've never ridden mayhem shapes, the Guild Factor is a great starting point...but be sure to follow the skill level and other advice, too. Firewire puts too much emphasis on age (skews volume way high), CI's calculator seems a bit low and Rusty's seems slightly high.
strange thing is, the GF recommends me 35 cL vol at max, but, a while back, Matt recommended I get 39.5 cL...he was way off as that board was a friggin boat on me
for those that say volume is overated, I disagree. Any bit of info to get you closest to the best shred stick possible, the first time, is a good thing...or you can buy three or more wrong boards in the search
Last edited by waterbaby; Nov 6, 2013 at 06:45 PM.
Nov 6, 2013, 07:24 PM #16Senior Member
- Join Date
- Oct 2012
You wouldn't have to build a box that's as long as your board. You'd need it to be only 1/2 as long as your longest board. Tape off the board someplace in the middle, dip the board vertically up to the tape, measure the displacement, flip the board and then measure the other side and add together.
But you wouldn't need to build anything if you had a large plastic trash can. The large 64+ gallon recycling ones are perfect because they're at least 41" deep and 24" wide (the diagonal is even longer) so you could easily measure a 6'8" board. And it wouldn't matter if you didn't know the can's capacity. Poke a hole near the can's rim and insert a small piece of PVC pipe or something to act as a drain. Fill the can until water starts pouring out of the pipe. Dip 1/2 the board and catch the water that pours out in a 5 gallon bucket. Measure what came out and there's your volume.
A while back I tried another way that was fairly accurate with a lot less work. The only thing I had to measure was the average thickness of the board using calipers. I think I measured every 4" along the stringer and every 3-4" out to the rail. It was a lot of measurements but it took less than 10 minutes. You can take the measurements closer together (every 1") in the nose and tail but you'll need to average those areas separately from the areas where you did the measurements every 3" apart.
You can either take your own picture of the board (straight on, centered on the deck) or download one from the Internet. I did it with a CI board and grabbed the image from their website. Just make sure you're grabbing an image of a board the same length as yours.
Load the photo into Photoshop, Gimp, or one of the many free programs that can count pixels. Scale the image to the actual length of the board, select the board's outline and let the program count the number of selected pixels. Then, draw a 1" x 1" square and get the number of pixels in that area, divide the total number by this number to get total surface sq inches, then multiply by the average thickness and convert in cu to liters.
I think the only accurate way would be displacement because even the volume numbers listed on the websites are from the CAD software and I'm guessing they don't take into consideration the glass, hot coat or gloss coat.
Nov 6, 2013, 07:54 PM #17
Nov 7, 2013, 03:03 AM #18Senior Member
- Join Date
- Oct 2012
Aug 2, 2016, 11:49 PM #19Junior Member
- Join Date
- Aug 2016
'I see dumb people' - 'Where?' - 'Everywhere.'
The gap between how smart you think you are and the nonsense written is blowing me away.
Got me so worked up I registered to post this knowing it's a 3 year old thread.
GF truly is no more than the ratio of body weight (in kg) to surfboard volume (in liters). Need a definition for it? --> kg/L
and the higher it is, the better it floats. Correlates enough?
Aug 3, 2016, 12:50 AM #20
^^^^^^ your the one not sounding smart here. First of all, your definition...gaff flat out said in his post that you quoted. A ratio between body weight and volume. Then you bring back up a 3 year old tread to act like an ass? Damn. Flipping people these days. Where's barry to call this guy a moron