Making a wide ROTV reach even wider with ‘3D’ steering

30 March 2017

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 an easy and effective 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.

ScanFish horizontal steering option in action

ScanFish horizontal steering option in action

Increase subsea survey efficiency with horizontal steering

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 minimised. 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.

Already have a ScanFish ROTV? Then all you need is an upgrade

This upgrade, enabling the ScanFish to swim left to right, requires modifications to the ScanFish subsea controller housing (extra ports for the flaps), replacement of side-panels, and a software upgrade of both firmware and the ScanFish III Flight software.

In other words, EIVA outfits the ScanFish model with an extra set of ‘fins’ to give it a greater range of movement, and then teaches it to use its new 3D steering ability.

3D steering for ScanFish

The 3D steering feature of the ScanFish ROTV models requires modifications to the ScanFish such as replacement of side-panels

The ScanFish range

The ScanFish III range is EIVA’s proven ROTV solution, which models include:

Quality materials and easily replaced wear parts characterise the ScanFish III range and contribute to a high ROI through a long service life. They are also designed for both smooth sailing and rougher weather, with a robust construction that reduces the risk posed to the ROTV in the water, and ensures the safety of the crew during deployment and recovery.

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