A - "Ocean" exceeding F8 and exceeding 4m significant wave height
B - "Offshore" up to, and including, F8 and up to, and including, 4m
waves
C - "Inshore" up to, and including, F6 up to, and including, 2m waves
D - "Sheltered waters" up to, and including, F4 up to, and including,
0,3m waves with odd wave to 0.5m.

Recreational Craft Directives applies to 2.5m - 24m sports and pleasure
vessels sold within EU, with some exclusions - for example replicas of
craft designed pre 1950. Pulls together a load of ISO standards
covering all aspects of vessel design and construction.

No more bureaucratic than ABYC/USCG standards and used by US boat
builders who want to market in Europe.

Lloyds standards, or indeed any other Bureau standards, are acceptable.