Ocean energy technologies are moving steadily from laboratory scale models to real scale prototypes and arrays of converters. In order to be reliable and cost-effective, all these devices require regular Underwater Inspection Repair and Maintenance (IRM) services. Nowadays the solutions of underwater inspection and maintenance are industrial class ROVs and divers. Since the current ROV solutions still do not provide a sufficiently low cost and high precision for many of the IRM operations (underwater welding, welding inspection, fouling removal, painting, valves operation, sacrificial anodes replacement, connecting underwater plugs, etc.), specialised divers are still being used by the industry.