Docking techniques and evaluation trials of the SWIMMER AUV: an autonomous deployment AUV for work-class ROVs

The SWIMMER Vehicle is a EU-Thermie funded project to develop a prototype autonomous vehicle capable of deploying existing work-class ROVs to subsea installations removing the need for continuous surface support vessels and long umbilical cables. To be able to accurately position and dock a large free swimming AUV, at depths up to 1000m after transits of up to 10km is particularly challenging. The deployment configuration mounts the ROV above the SWIMMER AUV. The ROV is inactive during deployment, and the AUV is completely self-contained in terms of power, thrusters and computer-control. During transit, the LRPS (long range positioning system) provides autonomous navigation to the seabed, together with top station monitoring. During docking, the SRPS (short range positioning system) directs the vehicle during the final 20 metres of descent and provides the necessary positional information for a precise alignment for a mechanical docking with a seabed station. When docked, the SWIMMER uses computer-controlled clamps that allow the ROV to be disengaged remotely from the SWIMMER while on the seabed docking station. In this configuration, power and communications are fed from the seabed network to allow the SWIMMER to recharge, and the ROV to be remotely controlled.