Ships are put under enormous stress throughout their working lives, buffeted by winds and heavy seas, often carrying oversized or heavy cargoes. To make sure that these ships retain the rigidity and stability that they were first put to sea with, and as a requirement of their being classed by classification societies, these ships must have a survey schedule to check that their structure is not in any way compromised throughout their working life. A surveyor, usually a qualified master mariner, engineer and naval architect, will conduct these visual surveys to assess, monitor and report on the condition of ship structure, machinery, navigational equipment, safety equipment, radio equipment, cargo and cargo gears. A normal classification survey would include an overall examination of the items for survey, detailed checks of selected parts, and witnessing tests, measurements and trials where applicable. Ships ‘in-class’ – that is covered by a classification society – are subject to a program of periodic surveys after delivery which are based on a five-year cycle and consist of annual surveys, an intermediate survey and a class renewal/special survey (held every five years), which may take several weeks to complete. Class is assigned to a ship upon the completion of satisfactory surveys, which are undertaken to check compliance with the rules of the classification society, usually at the time of newbuilding.