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Board volume & sail size

There are board volumes every 5 -10 litres in slalom boards. Which are then used on different type of slalom or slalom\freeride sails, such as the AC-F, AC-X and AC-K? We have prepared some extra info to help you choose better.

When learning to windsurf, the volume is essential on a board to have stability. Improving skills, we tend to buy boards which are having enough volume to uphaul in lighter winds, or not even that in stronger winds, or to have one board only to use in most conditions.

Years ago, the volume was important, while nowadays the most important thing is mainly the width of the board. The central width is what allows to use the different sail sizes. The tail width size is determining the maximum fin size to use. Therefore, already from the width of the board we already know for which type of sail size it will work, and for which type of wind.

Below a table which explains the idea in General

Board width (cm) Sail Size (m) Wind Range (knots)
55-65 5.0- 7.0 40-20 knots
65-75 6.5-8.5 30-12 knots
75-90 7.0-9.0 10-27 knots

Generally, each board size is recommended for more sail sizes, but ideally each board has its best fit with one sail size and fin. Unfortunately, we cannot all have 6 boards in our car, therefore even if one sail size will fit at it’s best, a bigger and a smaller size will still fit well on the same board to have the right fun and performance.  Taking a 70cm board for example, the best sail will be a 7.8 sail, but will work good with an 8.5 sail or a 7.0, which is still an amazing wind range, as in this example, you could get planning in 12-14 knots and hold it up to 28 knots.  This does not depend on the weight of the windsurfer. A lighter windsurfer will use the same combination in lighter wind, against a heavier sailor.

PWA riders do not have problems in having to choose boards as they are allowed to use by rules, 3 board and 6 sails. They use normally 2 sails with one board, and they also still prefer one particular sail size on each board size. This is how they are normally equipped:

Board width (cm) Sail Size (m) Wind Range (knots) Fin size (cm
58-64 5.0- 7.2 50-25 knots 31-34
68-73 7.2-8.6 28-11 knots 36-38
80-85 8.6-9-2 18-7  knots 43-47

Logically, the wider the board, the better it is for lighter wind as it allows to carry bigger sails and bigger fins.  Often people tend to put too big sail sizes on smaller boards to plane earlier. It’s often useless if the sail and board are not proportional. Example, if you have a 68-wide board, and you put a 9.0 sail, the extra weight and power of the sail will just sink the board more heavily to the water. The fin will be too small to hold the power and the result is just a spin out, a heavier feeling, and the planning will be at the same time, if not worse than with the right smaller proportional sail. So, there is no short cut to try to hope to get planning on a smaller board, by just buying a bigger sail. It could be better to buy a bigger board and keeping the same sail.

The same goes to the opposite direction: using an even smaller sail on a bigger volume board to have more control in stronger wind. The volume of the board, in stronger wind and bigger waves, than what it has been made for, will just catch more wind, and fly all over the water without letting you have control. The too small sail does not have the power and profile to keep a bigger volume board on the water.

We have prepared for you some general tables for you to find the different combinations for the best fit! Enjoy the study!

RACING MODE AMATEUR MODE
COMBINATIONS Volume Board width AC-One, AC-K Fin Size AC-One, AC-K Fin Size
A 75 55 5.0, 5.2 30 4.6 AC-X 28
B 85 59 5.6- 5.8, 5.2 31 5.0-5.2 30
C 95 63 6.3- 6.3, 5.8 32 5.6- 5.8 32
D 100 67 7.1- 7.2, 6,4 34 6.3- 5.8 32
E 105 71 7.8-7.8,7.2 37 7.1-7.2, 6.4 36
F 115 75 8.6-7.8 42 7.9-7.2 39
G 125 80 8.6-8.5 44 7.9- 7.8 40
H 135 85 9.2-9.4 47 8.6- 8.5 44
Weight KG 50-60 60-75 75-90 90-100+
Wind in KTS Recommended Combo
6-10 E F G H-G
10-16 D D-E F G
16-21 B-C C-B E-D E
21-25 B C-B D D
25-31 A B C-B C
35+ A A B B
           
Weight KG Ideal Light wind Combo  Ideal Strong wind Combo
50-60 G D
60-75 G OR F D OR C
75-90 F C OR B
90-100+ E A
Weight KG Best combo if looking for having only 1 slalom board combo.
80-100 G
65-80 G OR F
50-65 F
90-100+ E

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