For the choice of your sail it is important to know how strong the wind blows. In the section "Equipment", we explicitly explain which equipment is appropriate for which wind. But how do you know how strong the wind is? Not everyone carries a wind gauge in his pocket. That's also not necessary because those who know what to pay attention to can determine the wind power with just a look at the water.

Wind speeds can be measured in different units, for example in metres per second (m/s), in knots (kn) or in kilometres per hour (km/h), too. In European countries, the unit Beaufort (Bft.) is mainly used, but often simply called "wind force". The Beaufort scale goes from 0 to 12 Bft. (see below). In English speaking countries the nautical knots unit is more common.

For everyone already has a sense for speed displayed in km/h from driving a car, the table below contains the conversion of km/h into Beaufort and knots. In this table, you also find the description of the water surface and the environment to a given wind force, with which you can find out relatively exact how strong the wind must be blowing at the moment with a little bit of experience.

For beginners and upcomers, a wind force between two and five Bft. is best. Below that, the wind is very light. However, take care: as of six Bft., beginners have no business being on the water – it can become dangerous.