The CE category is a rating system used in the EU to rate the seaworthiness of a (sailing / motor) boat.  This CE category is mainly used by European boat builders although some US sailboat builders start to build boats to this specification.  The European Directive specifying the CE Categories for recreational boats between 2.5 and 24 meter in length is the EU Recreational Craft Directive (RCD).

The CE categories are:

A: Ocean.

Designed for extended voyages where conditions may exceed wind force 8 (Beaufort) and wave height of 4 meter (13' ft).

B: Offshore.

Designed for offshore where conditions up to, and including, wind force 8 (Beaufort) and wave height of 4 meter (13' ft).

C: Inshore.

Designed for voyages in coastal waters, large bays, estuaries, lakes and rivers where conditions up to, and including, wind force 6 (Beaufort) and wave height up to 2 meter (6'6" ft).

D: Sheltered water.

Designed for small lakes, rivers and canals with wind up to, and including, force 4 (Beaufort) and wave height of 0.3 meter (1' ft).