Definitions of Boat Design Categories
Designed to operate in winds up to Beaufort force 6 and the associated wave heights (significant wave height up to 2m). Such conditions may be encountered in exposed inland waters, in estuaries and in coastal waters in moderate weather conditions.
This craft is designed to operate in winds up to Beaufort force 4 and the associated wave heights (occasional maximum waves of 0.5m height). Such conditions may be encountered in sheltered inland waters, and in coastal waters in fine weather.
Designed for extended voyages where conditions may exceed wind force 8 (Beaufort scale) and significant wave heights of 4 metres and above but excluding abnormal conditions such as storm, violent storm, hurricane, tornado and extreme sea conditions or rogue waves. Vessels are largely self-sufficient.
Designed for offshore voyages where conditions up to, and including, wind force 8 and significant wave heights up to, and including 4 metres may be experienced. Such conditions may be encountered on offshore voyages of sufficient length or on coastal waters when unsheltered from the wind and waves for several dozens of nautical miles.