The EIVA ScanFish remotely operated towed vehicle (ROTV) models have always been able to follow the seabed, keep a fixed depth, or undulate up and down through the water. Up until now, it has not been possible to also have the ROTV effectively move side-to-side.
However, after trying out various setups and running tests with customers to ensure feasibility, ScanFish ROTVs have an additional way to move through the water. EIVA has developed a way to modify existing ScanFish ROTV models with ‘3D’ steering – that is, the ability to not only swim up and down, but sideways as well during subsea survey operations.
An optional upgrade to the ScanFish ROTV allows the operator to control not just the vertical but also the horizontal movement of any ScanFish ROTV through the water, with a fast steering response and a wide range of lateral movement of +/- 25 m.
This ability to steer sideways is particularly useful when sideways currents influence the ROTV position, long tow cables are used in deep water, or when the runline is not straight in cable and route surveys, among other situations. It also increases survey efficiency, since overlap of sensor coverage can be reduced and the number of re-surveys required can be minimized. The upgrade is available on all ScanFish models, but is especially relevant to the ScanFish Katria model, in its terrain-following operation mode for wide-sweep UXO surveys.
Moreover, 3D steering can be used with NaviPac – the navigation and positioning software product of EIVA NaviSuite – whose auto-pilot feature will allow for the ROTV to follow a predefined runline as instructed by the software.