Patent attributes
An inspection, monitoring, maintenance or construction task is performed on a subsea structure by using an underwater vehicle to carry a submersible package to the subsea structure. The package comprises a tool or sensor arranged to perform the required task on the subsea structure, and an on-board power unit and controller arranged to power and control the tool or sensor. The package is transferred from the underwater vehicle to be supported by the subsea structure. The underwater vehicle can then stand off from the package. While the package is supported by the subsea structure, the tool or sensor of the package performs the required task on the subsea structure, powered and controlled by the on-board power unit and controller of the package.