Abstract: Apparatus for servicing a structure has one or more buoyancy chambers attached thereto such that the angle of the apparatus when floating may be adjusted. The attachment may be by a pivotal connector with a pivot point at or near a midpoint or centre of gravity of the structure. The apparatus may comprise a frame that can be opened to fit around the structure to be serviced. This may facilitate attachment of the apparatus to angled structures in an aquatic environment.

Abstract: A bypass module is provided for removable connection in series along an elongate structure between first and second drive and/or servicing modules. each of which may be selectively closed around the structure or opened to enable removal from the structure, wherein the bypass module is actuable to move the first and second modules relative to each other in a direction towards and away from the structure, so that one of the modules is moved away from the structure while the other is closed around the structure.

Abstract: Apparatus for servicing a structure has a buoyancy arrangement comprising a series of buoyancy chambers and a gas supply connected to a first one of the chambers, the chambers being interconnected so that. as gas is supplied to the first one of the chambers and that chamber fills with gas. the gas then begins to escape into the next one of the chambers in the series until that chamber is full of gas, and so on until the series of chambers is full of gas. The supply of gas can be controlled so as to achieve the desired level of buoyancy. The gas may be supplied from an external gas supply, or from a cylinder carried by the apparatus.

Abstract: Apparatus for servicing a structure comprises a frame for assembly around the structure, the frame having least one pair of first and second arms pivotally attached at proximal ends thereof to the frame and carrying respective rotating members arranged to contact the structure and driveable to move the frame along the structure.