Abstract: For cleaning and/or painting the exterior of a ship hull while the ship is in dry dock, one or more staging devices are provided. Each includes a metal framework tower supporting a vertically movable elevator assembly that comprises a trolley, from which a variably laterally projecting platform is supported on articulated, cantilevered arms. Adjustable, non-porous shrouds enclose a volume of space between the outside of the tower and an increment of one side of the exterior of the ship hull, from above, fore, aft and outside. Cleaning and painting operations are conducted from the platform on the hull increment, and debris is removed from the dry-dock deck area enclosed by the shroud, after which the device is moved by crane, typically twenty feet (6.1 m), towards the ship's bow or stern. The shrouds are then adjusted so that a further hull increment can be worked on. The trolley and extension-retraction of the platform support arms are operated by electrohydraulic winch and hydraulic cylinders, respectively.