A large number of pipes and cables on the seabed need to be protected from anchors, trawlers and other risks. This is where specialty vessels enter the picture. Rock dumping vessels, or fall pipe vessels, can very precisely cover a submerged pipe or cable with rock. These types of operations are performed in waters up to a depth of 3000 meters below sea level.
To achieve this, QINSy interfaces to a myriad of survey systems mounted on the vessel itself and on the fall-pipe ROV, potentially some 3000 meters below the vessel. With its advanced route planning capability, QINSy can direct the vessel over the correct track by sending the Dynamic Positioning system the coordinates of the track. The fall pipe ROV is typically positioned by an Ultra Short Base Line (USBL) acoustic system that is interfaced to QINSy.
Due to the depth of the ROV below the sea level and other external influences the USBL signal can sometimes be distorted, resulting in unstable positioning of the fall pipe ROV, and consequent interruption of the dumping operation. To minimize downtime, QINSy incorporates sophisticated Kalman algorithms to filter out position jumps and create a steady position of the fall pipe ROV.
Usually the fall pipe ROV is equipped with multibeam systems fore and aft in order to simultaneously perform a pre-dump survey and post-dump survey as rockdumping proceeds. In this scenario, the attitude and heading of the ROV must not only be accurate, but be rigorously time tagged along with all the multibeam data itself to achieve perfect DTM mapping. By importing a designed DTM that shows the intended rock longitudinal and lateral profiles, the pre-dump and post-dump DTMs may be compared in real-time with the design DTM to show deviations of actual profiles from intended profiles.