Class society
A recognised organisation that surveys yachts to defined construction and maintenance standards. The major IACS members are Lloyd's Register, DNV, Bureau Veritas, RINA, ABS, and ClassNK.
Class societies set construction rules, conduct surveys at construction and through service, and issue and maintain class notations. Class is required for most commercial yachts and increasingly for large private yachts above 500 GT. Common notations on superyachts include LR 100A1 SSC, DNV +1A1 LC Yacht, BV I HULL MACH Yacht, RINA C+ Yacht. Class operates parallel to flag-state inspection; the class society can act as a Recognised Organisation under flag delegation.