Classification survey

A classification survey is an inspection by a recognized organization, the classification society, to confirm a ship still meets the class rules under which it was built and is fit to keep its class certificate. The cycle runs five years: an annual survey within three months either side of each anniversary date, an intermediate survey in the window from before the second to after the third anniversary, and a special, or renewal, survey at the five-year mark with internal tank examination and thickness gauging. Two bottom surveys fall in the cycle, one concurrent with the renewal. A lapsed survey suspends class and voids statutory certificates, so the ship cannot trade.