Boats are classified into different design categories. Below is an explanation of each category.

Category A

This vessel is designed to operate in wind strengths greater than 8 on the Beaufort scale and with significant wave heights of 4 meters and above (see Reference 1), and is largely self-sufficient. Extreme conditions such as those that can occur during hurricanes are not included here. Such conditions can occur during long voyages, for example crossing oceans or within the coastline when there is no cover for wind and waves within hundreds of nautical miles.

Category B

This vessel is designed to operate in wind strengths up to 8 on the Beaufort scale and associated wave heights (significant wave heights up to 4 meters see reference 1). Such conditions can occur on extended sea voyages or in coastal waters when there is no shelter from wind and waves within tens of nautical miles. These conditions can also occur during voyages on inland seas of sufficient size where this wave height can also occur.

Category C

This vessel is designed to operate in wind strengths up to 6 Beaufort on the Beaufort scale and the corresponding wave heights (significant wave height up to 2 meters, see reference 1. Such conditions can occur in open inland waters and in coastal waters in moderate weather conditions.

Category D

This vessel is designed to operate in wind strengths up to 4 Beaufort and the associated wave heights (occasionally maximum wave heights of 0.5 metres). These conditions can occur in sheltered inland waters and in coastal waters in fair weather.

Reference 1: The significant wave height is the average height of the highest of one-third of the waves, which corresponds approximately to the wave height estimated by an experienced observer. Some waves can be twice as high. The categorization is the result of theoretical stability criteria. In practice, it is not recommended to go on the water in heavy weather, and certainly with the maximum number of people. Adjust your sailing area to the weather.