Crawler Data Sheet (PDF)

The ROC.si (pronounced “rock-see”) is a dynamic remote sensing platform, equipped with - but not limited to - an obstacle sonar, cameras for visual inspection and video recording, and a cable tracking system that can detect cables buried to several meters. It can follow cables automatically, constantly collecting depth-data, burial status and video imagery. This automatic tracking of buried cables by the ROC.si has been carried out in numerous shallow-water locations where the use of a conventional ROV (remotely operated vehicle) was impossible due to the strong currents or lack of sufficient water depth.

When it is not automatically tracking a cable, the Crawler is controlled remotely using a joystick similar to those used for computer games. All the controls going from the operator to the Crawler as well as all the data collected from Crawler - the obstacle sonar, the cable tracking system, the motion sensor, and live video - are converted into TCP/IP and sent via fibre optic cable back to the surface. Using common network technology for the communication between the Crawler and the control unit makes the system very flexible and leaves the possibility open for adding new sensors and equipment.

The ROC.si was jointly developed by Fugro OSAE and Meerestechnik Bremen specifically for shallow water cable inspections. It is 3.3m long, 2.3m wide, 1.5m tall, weighs 1300 kg, can operate at 3 knots, and is rated down to 200m water depth. At present it is equipped with 2 lights, four cameras, a sonar obstacle detector, a USBL positioning beacon, and a cable tracking system. Click on the link above for a specification sheet.

The Crawler in the Irish Sea
The Crawler was deployed to carry out two wind farm connector cable inspections in the Irish Sea during the summer of 2010. The positioning and burial-depth data of the power connector cables extending from the British coast to the Burbo Bank and Barrow Offshore wind farms, each consisting of approximately 25 route kilometers, was successfully acquired in both cases.

Electrical power cables, potentially massive in size and weight and always very costly, carry the electricity generated from a wind farm back to a substation on land. Annual inspections during the first years are strongly recommended – mandatory in some countries – for the safe and continuous operation of wind farms. An exposed or free-spanned cable – one that is hanging from one point to another without touching the seafloor in the middle – is much more likely to become damaged or caught by fishing equipment or an anchor, ultimately reducing the effectiveness/conductivity and longevity of the cable. Currents regularly alter sand formations on the seabed, not only forming high sand dunes but also removing it from other areas, potentially leaving a cable exposed. The picture below from a project in 2008 demonstrates the tracking and burial depth of a cable where sand has accumulated to over 4 meters as measured by the ROC.si.

Path of the Crawler in the English Channel

The difficulty with offshore cable inspections, however, is that waters can be very shallow for several kilometers and, in effect, require an amphibious robot like the ROC.si to conduct the work. These waters are often too shallow for a vessel or an ROV and, with cables buried deep into the seabed for protection, special sensors are required for tracking them, determining their burial depth, and recording their position and water depth.

During the Irish Sea project, 53 kilometers of cable were inspected, about half of which would have been virtually impossible with any other vehicle. For this particular project, the ROC.si was equipped with a passive cable tracking system, a profiler, an altimeter/bathymetric recording system, an obstacle avoidance sonar, and three cameras. The vehicle was also fitted with either a GPS receiver for positioning during surface and shallow water operations or a USBL beacon when fully submerged.

Fugro OSAE Receives an Award for the Crawler
On 13 May 2009 Fugro OSAE GmbH proudly received a award from the “365 Places in the Land of Ideas“ for the ROC.si (Remotely Operated Crawler for Subsea Inspection). The “Land of Ideas” initiative has the Head of State, Federal President Horst Köhler, as honorary spokesman to demonstrate the innovations originating from Germany.

(From left to right) Dr. Klinkhammer, M. Stender, T. Viergutz, Prof. Dr. Thomsen at the Oceans Conference (Click image to enlarge - 900k)

During the award ceremony at the Oceans ’09 Conference which took place in Bremen, Germany, Professor Dr. Laurenz Thomsen, expert of underwater technology and professor of geosciences at Jacob’s University in Bremen, explained that shallow water areas with strong currents are very important areas for energy exploration. The Crawler ROC.si is an innovative tool to support pipeline and cable work in these areas.

At the awards ceremony, Dr. Martin Klinkhammer of the sponsor Deutsche Bank said: "This fascinating diving robot is a technical masterpiece. It can even work in strong currents. The vehicle is equipped with special equipment to examine underwater power or phone cable systems, whether buried or not. Thus, with the ROC.si, Fugro OSAE GmbH is an important contribution to our technological future."

Manfred Stender of Fugro OSAE GmbH is pleased about the award: "We are very proud to be a selected location in the Land of Ideas. Fugro OSAE has over 25 years experience with innovative technology in marine survey, and the award demonstrates that we continue to develop new technologies in order to remain a leader in the field."