OSD Designs Bourbon Seismic Support/Chase Vessel Series
Offshore Ship Designers has been chosen to design a series of six new fuel-efficient seismic support/chase vessels ordered by French offshore major Bourbon to be built at Dubai’s Grandweld Shipyards. The 53m vessels will have a fuel efficient hybrid propulsion system delivering a flexible economic solution for the varied conditions required to support seismic survey vessels including transit speed, slow speed escort and support work and a high degree of manoeuvrability.
“Neil Patterson, managing director of OSD-IMT, the UK arm of Offshore Ship Designers, continuous: “We worked closely with Grandweld during the tender period, following their selection as one of the short-listed bidders. We assisted Grandwell technically during the successful contract negotiation process, and are pleased to have been entrusted with the design of these new vessels.” Bourbon has decided to build these vessels at Grandweld Shipyards in Dubai. The vessels will be chartered by Bourbon to CGGVeritas with delivery of the first vessels set for the end of 2012. They will be used to support the fleet of CGGVeritas seismic survey vessels operating all over the world, providing them with services including crew change, fuel delivery, storage, assistance and support during at-sea maintenance operations.
Operational Requirements
Operational requirements of the design include cargo runs from port to the mother ship, the transfer of fuel, potable water, dry and refrigerated stores and general cargo to the mother ship, the transfer of crew to and from the mother ship, accompanying the mother ship when conducting seismic operations, towing of the mother ship when conducting seismic operations, and the retrieval of streamer cables.
Propulsion Modes
Key feature of the hybrid propulsion system are two main marine diesel propulsion engines, two controllable pitch propellers in nozzles, two main gearboxes each with a PTI electric propulsion motor and three diesel driven generating sets, and two electrically driven bow tunnel thrusters. The diesel-mechanical mode using main engines is only used for the transit operation (service speed 11 knots). For chase and slow speed operations (up to 6 knots) the vessel uses its diesel-electrical mode with main engines declutched using PTI propulsion motors powered by the gensets. For towing operations the vessel uses boost mode with main engines and PTI propulsion motors (powered by the gensets) engaged. Service speed in boost mode is 11.3 knots; bollard pull in this mode is 50 t.
Main Particulars
Length 53.8 m
Beam 13.0 m
Depth 5.8 m
Load draught 4.8 m
Cargo fuel capacity 850 cu. m
Marine gas oil fuel 260 cu. m
Potable water 100 cu. m
Refrigerated and dry storage capability as well as space on deck for stowage of stores containers