The 140 ft. catamaran seismic survey vessel Ms. Cordelia was delivered to Global Geophysical Services, Houston, TX. The all aluminum vessel was converted from a prototype high speed low wake passenger ferry that had not been completed or put in service. The conversion design and engineering was done by the naval architectural firm of Guarino & Cox, LLC, Covington, LA. Seacraft Shipyard carried out the conversion work at their facilities in Amelia, LA.
The unfinished vessel was considered an ideal candidate to be converted for its intended use primarily due to the large deck area available and its shallow draft. The MS. CORDELIA will be capable of performing inshore shallow water seismic survey work laying and retrieving cables in as little as 6 feet of water.
The slender catamaran demi-hulls make the vessel extremely fuel efficient at a continuous cruising speed of 12 knots and comfortable in the short steep waves often found in inshore locations. The major modification to the hull form was the removal of the large water jets originally installed and altering the stern lines to utilize conventional propellers in shallow tunnels. A continuous maximum speed of 15 knots is obtained through this arrangement with power provided by two new 700shp Lugger diesel main engines engines.
An operating speed of 2 to 3 knots was a requirement during deployment and retrieval of the special cables used while surveying. This would normally be impossible to achieve with the easily driven catamaran form but the naval architects of Guarino & Cox devised a scheme using oversized independent rudders capable of being splayed outboard up to 60 degrees that deflect the propeller wash and act as water brakes.