A private body that sets a ship's construction rules, surveys it periodically and grants the class on which its insurance depends.
A classification society sets the technical rules for building and maintaining ships, verifies compliance through periodic surveys and grants a class accordingly, certifying that the vessel meets a recognized standard. These bodies are private, often two centuries old, and the twelve leading members of IACS cover most of the world's tonnage. Their role goes beyond the technical: states delegate to them part of the statutory surveys required by international conventions, banks condition their lending on class being maintained, and hull policies carry a classification clause that suspends or voids cover if class is suspended, withdrawn or changed without the underwriter's agreement. Their liability toward third parties remains an open question, courts being reluctant to turn a certifier into the insurer of last resort for the victims of a sinking. The problem solved is the information gap between an owner who knows its ship and an underwriter, charterer or banker who will never see it.
In Marc Rich v Bishop Rock Marine, known as The Nicholas H, the House of Lords held in 1995 that a classification society owed no duty of care to the cargo owner. The ship, cleared to sail on after a temporary repair, sank with a cargo worth 5.7 million dollars, of which the shipper could recover only 500,000 dollars from the owner, stopped by its limitation of liability.
classe du navire, IACS