The ScanFish III is a sophisticated underwater remotely operated towed vehicle (ROTV) for use in oceanographic operations in conjunction with a multitude of other equipment and software. 

The ScanFish III is a wing-shaped ROTV with port and starboard flaps for stabilisation and movement in the water column. Inside the ScanFish III body, there is room for carrying sensor equipment, with access to the water column through openings in both side panels. It is also possible to have equipment mounted on top of and below the body of the ScanFish III. 

The ScanFish III is towed behind a ship for propulsion. It moves up and down in the water accelerometer, a magnetometer, a gyroscope, and an echo sounder for measuring elevation from seabed, and a pressure sensor for measuring depth. This enables the ScanFish III to be steady in the water, even at high speeds, because of continuous and autonomous control of the flaps. This, in turn, makes it a stable platform for underwater operations. 

The ScanFish III features three basic operating modes: 

    • Fixed Depth mode: the ScanFish III maintains a stable depth beneath the surface 

    • Follow Seabed mode: the ScanFish III maintains a stable elevation above the seabed despite fluctuating bottom conditions 

    • Undulate mode: the ScanFish III moves up and down in the water column in an undulation pattern  

While in operation, the ScanFish III is connected via Ethernet to the surface for constant monitoring and control. For some models, the uplink also enables constant transmission of data from a variety of sensors to EIVA NaviPac or other software. 

Distinct models with distinct features exist to cover a variety of operational needs. These are described in Chapter 2 System overview

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