For yachts under 24 meters there are different classifications like:

EC Category  
A – Ocean: > force 8, > 4 m waves
B – Offshore: up to force 8, up to 4 m
C – Inshore: up to force 6, up to 2 m
D – Sheltered: up to force 4, up to 0.3 m (occasional 0.5 m)


Who and how do they decide which category a boat is designed or built for?

For typical/popular 65 to 78 foot cruising catamarans please estimate what percentage fall in each category.


Are there other classifications?   What do most designers of such catamarans design for?