Class certificate

A class certificate is the document a classification society issues confirming that a ship is built and maintained to its rules and holds a valid class. It records the class notation, the survey status, and any conditions or recommendations outstanding. Class is the basis on which the flag state, insurers, and charterers accept the vessel: hull and machinery underwriters require class in force, and a charter party warranty of class lets a charterer reject a vessel that has lost it. The certificate stays valid only while the periodic surveys (annual, intermediate, and the five-year special survey) are kept up.