A hull cleaning system is disclosed that comprises a below-waterline hull cleaning head arranged to clean an underwater portion of a hull in-situ, a location determining system arranged to produce location information indicative of the location of the hull cleaning head relative to the hull, and a hub facility remotely located relative to the hull cleaning head. The hub facility is arranged to store the location information, and the system is arranged to send the location information to the hub facility for storage at the hub facility so as to thereby provide a record at the hub facility of clean portions of the hull that have been cleaned by the hull cleaning head and fouled portions of the hull that have not yet been cleaned by the hull cleaning head. The system is also arranged to provide on-line access to the location information stored at the hub facility so as to thereby enable cleaning to continue at a subsequent time using the stored location information.