Remotely operated vehicles (ROVs) are used to inspect underwater structures.

Who supplies them

Manufacturers: ECA Hytec, Saab Seaeye and Seatronics.

Operators: Film-Ocean, Fugro, James Fisher Marine Services and ROVCO.

Key facts

Inspection class ROVs are used to inspect the substructure, anchors, and mooring systems below the water line. They are also used to inspect the cable route, particularly in areas at risk of scour or other sea bed movements, and at other high-risk locations, such as crossings with other cables.

Inspection ROVs typically have a speed of 3 to 5 kn, weigh 8 to 12 kg and have dimensions 1 m x 0.7 m x 0.5 m.

They are equipped with propulsion systems, lighting, and a range of imaging equipment.

ROVs are launched from a DP2 vessel equipped with an A frame or moon pool. ROVs are attached to the vessel by umbilicals or tether cables which transmit electrical power, data, and optical signals. Tethers and umbilicals are usually strengthened with steel wire, to support the mechanical loads of the ROV underwater.

Radio waves don’t travel far through water, so it’s not possible to operate an ROV with wireless technology. There are acoustic and optical modem technologies that may someday enable wireless operation.

The continued development and use of unmanned subsea inspection vessels is an area of innovation.

What’s in it

Guide to a Floating Offshore Wind Farm