^^^ decrep - yes correct but I think it was red thumbed as trying to add weights on a board, no matter how calm will surely result on them falling off as you try to "sink it level"..... result is you get the sh!ts with it and go home 
The only easy suggestion I have ever seen - and seems to be a new one - is Chris' wheelie bin. But don't tell him I said that.
^^^^ after it has bulged cos it is full, THEN you have water at the top, and insert half the board vertically, causing spillage
Then remove board.
Any change in the bulge during that process would be negligable. Like a litre at most.
Adding weights and try and have it sink evenly (level) so weights don't fall off = hours of fragging around. Insert into water and measure spillage - about 1/10th the time with an acceptable tiny error.
He is trying to ascertain if the board is 80L or 90L - not 88.2L or 89.05L.
Had to laugh at all the suggestions...some quite scientific and some downright silly...but in reality....what is the approach when buying a new board? (lets assume the person, not me, has been windsurfing for at least a year and has good balance on a beginner board etc but may not necessarily be able to deep water start..so uphauling may still be required).
Do you take the volume of the board, subtract the weight of rig and it should be equal or more to the weight of the individual?
I know I will probably get a lot of "it depends" but for arguments sake, lets say the person is interested in 2 boards...a flat water cruising board and a wave board...what differences would there be and what sort of volume are you looking at? Assume the person is 80KG which would be the average weight of a male.
If you had an anchor point at the bottom of a pool you could use a winch and a spring gauge to see how much force is required to pull it under water. same effect as loading weights on top.
Beatlloydy, it depends on what kind of sailing you are doing, wind strength and sail sizes you want to use much more than what you weigh. Wave board you usually want the smallest you can get away with. If it's windy and you're powered up you can go way below your body weight in litres, if it's marginal you want something closer or a bit above to give you enough float to get out. For flat water you need to match the board to the sails. All manufacturers give a recommended sail size range for each board.
I was more talking about the ways manufacturers measure boards, not so much about the board at the start of this thread. That board is easy, it's precisely 364 'onions tied to my belt'...
My only point was that production boards are all over the place, so it's pretty clear that they have no set way to measure them that eliminates error. I'd trust Fanatic with a volume, cause they're CNC, the rest should have +/- 5L..
Ahhh Virtual Volume, that Dark Science where by moving the thickness to the rails you increase surface area and therefore the buoyancy...
When will Scientists learn that some things just shouldn't be tampered with..
) & used my 5.8 Ezzy. It planed in no time and it's the fastest I've ever been on a board. Water start in chest deep water was a breeze.
I found an empirical method on the net a while ago which I've found to work well on about 5 boards I've tried. The method is as follows:
"Estimation of the volume of a board (empiric made - don't look for any logic):
1. Measure the board where thickest.
2. Measure the circumference of the board with intervals of 20 cm (starting 10 cm from the stern).
3. The measured circumferences of the board are put into the formula: Circumference/221*20*thickness/13, which
of course is calculated.
4. The sum of the results (from "3.") tells the volume of the board in liters. "
Here's an example that I did for a mistral equipe 1 (quoted volume of 235 L)
thickness (cm)
16
circumferences (cm) / formula
63.0 7.0
83.0 9.2
101.0 11.2
117.0 13.0
128.0 14.3
134.5 15.0
140.0 15.6
144.0 16.0
146.0 16.3
147.0 16.4
146.5 16.3
143.5 16.0
139.0 15.5
131.0 14.6
121.0 13.5
103.5 11.5
79.0 8.8
39.0 4.3
volume (sum of right hand column) 234.6 L
It's not as hard to do as it sounds, you just need a string and tape measure for the circumferences or one of those flexible things you use to measure you're waist.
I can't for the life of me determine the volume of my board.
It keeps bloody changing....
...seems the choppier the conditions, the louder the board!!
That sounds like it might have been an original Equipe, which was ~220 L. There were three versions, the equipe, equipe 1 and equipe 2.
Anyway, the above method is an empirical method, which to me means someone's come up with a method and formula that consistently reproduces the quoted volumes of production boards (which I have found it to do well), and which can then be used to find the approximate volume of an unknown board. But this does mean that the technique is limited to the accuracy of the numbers quoted for whatever production boards have been used to develop the technique.
Another quick and easy method is :
Turn the board upside down
Look around near the stringer close to the fin
When you find some writing read it
One of those numbers may or may not be the volume
(Of course if you have already cut it into 1cm x 1cm x 1cm blocks you may have to partially re-assemble first)
The trouble with all this is that even of you end up accurately measuring your board, you are presuming that the volume of new boards is stated accurately, which I somehow doubt.
You're just better off working out your requirements and talking to a few people to get an idea of what nominal volume board you should get. Better still if you can test sail a couple of boards.
It would be quite simple if you had access to a tank or cistern that you knew the exact volume of and the board would fit into.
Simply hold the board underwater with a stick or something and remove water until the tank with the board submerged is at the mark where you know it's exact given volume. Then remove the board and add water a liter at a time until it is full to the mark again.
Anything else is just guestimating.
Actually you don't even need to know the volume of the tank of water, just mark the side of the tank when full with the board submerged then remove the board and add water a liter at a time until it's to the mark again.
Simply put, you just need a tank big enough to hold the board.
You can tie barbell weights to the board to hold it down and let the water go still then when you remove the board just leave the weights in the water and refill.
FWIW we guesstimated it to be 'in the nineties'.
Last weekend I purchased a second hand 100ltr JP Freestlye III, now I'm hangin for some wind.
Noticed similar board @ www.seabreeze.com.au/forums/Windsurfing/New-South-Wales/Wavesailing-video-off-Long-Reef/. Now I have a skill level to aim for.
it's easy...
take out the plug fill the board with water.
then remove all the water and measure it.
make sure you get it all out for accuracy.
by this method i found my nude chopper had a greater volume than actually stated on the board...it held a lot of water.
Some shapers include the sandwich material thickness in the volume calculation.
Normally around 10 Litres.
For example a board which has an 85 Litre EPS core (CNC calulated) will be rated as a 95 Litre board.
Not sure how much a double sandwich skin would contribute to actual float??
Why dont we include the footstraps and deckpads in the volume too..
