In-water survey

An in-water survey is a class examination of the underwater hull, carried out with divers or a remotely operated vehicle while the ship is afloat, accepted by the society in place of one dry-docking. The surveyor reviews a live video feed of the shell plating, sea chests, rudder, propeller, and the anti-corrosion system, with most societies requiring underwater visibility of two to three meters. It can be credited for only one of the two bottom surveys due in the five-year cycle, and societies usually limit it to vessels under 15 years with a sound hull coating and an in-water-survey notation. Heavy fouling or poor visibility forces a return to dry dock.