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 some examples, where the figures are calculated in an Excel spreadsheet.