Swimmer: final sea demonstration of this innovative hybrid AUV/ROV system

With the increasing depth of offshore oil and gas fields (exploration: >2500 msw; exploitation: record at 1850 msw), the cost of traditional ROV (remotely operated vehicle-tethered) operations for IMR (inspection, maintenance and repair) tasks will represent a growing part of the total field´s operational expenditures and the maintenance of subsea installations throughout the life of a field (typically 15 to 20 years) will be one of the main technical challenges. Cybernetix, a leading French subsea robotic manufacturer, developed, in collaboration with Ifremer, the University of Liverpool and TotalFinaElf, an innovative hybrid ROV/AUV (autonomous underwater vehicle) concept, called Swimmer, for deploying an ROV on a deepwater field without the need for long and heavy umbilicals, special support vessels and their associated costs. A standard ROV is automatically carried by an AUV shuttle to a subsea docking station installed close to equipment which requires regular IMR interventions (wellheads, manifolds, ...). The docking station is linked to the surface via a permanent umbilical which allows powering and real-time control of the ROV when the AUV shuttle is connected to the subsea station. Swimmer is not only a drawing board concept, it has now been fully integrated and tested in workshop and in shallow water. In June 2001, the complete acoustic systems have been tested offshore and the shuttle flew for the first time in AUV mode in the open sea. In September 2001, the first fully automatic docking has been performed in shallow water at Cybernetix´ Marseilles harbour facilities. Finally, complete offshore demonstration has been performed during the second half of October 2001. The aim of this paper is to present the Swimmer concept and the results of the final sea trials.