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February 2005 23 The American Bureau of Shipping (ABS) has issued Approval In Principle (AIP) to a new liquefied natural gas (LNG) tank containment system and carrier design developed by Houston-based Ocean LNG Inc. The tank design consists of a cylindrical tank with spheri- cal dished ends. The 180,000 cu. m. carrier design fea- tures five of these large 36 m diameter and 40 m high cylinder tanks each holding a volume of 36,000 cu. m. of LNG. Ocean LNG claims that the design maximizes the void spaces in the ship's hull, yet still provides full access around the tank for inspections of both the insu- lation and tank structure. Compared to the traditional spherical LNG tank containment system, the Ocean LNG tank system is expected to increase cargo capac- ity within the same main hull dimensions by an esti- mated 25 percent compared to spherical LNG tank sys- tems. The Ocean LNG proprietary tank design is fashioned according to IMO Type B independent tank design and based on the leak before failure principle. The tanks are designed to minimize filling restrictions due to sloshing effects. A detailed sloshing analysis of the tank and pump tower designs was recently been completed by ABS. "The marine and offshore industries frequently develop novel applications in response to industry and market demands," said Philip Rynn, Senior Staff Consultant, Engineering, ABS. Rynn certified the design principles of Ocean LNG's tank containment system and carrier design. Circle 30 on Reader Service Card KING-GAGE ® LevelBAR Tank Level Indicator Analog LED column graphically displays tank level as total volume and/or depth. Replaces fluid-filled gages Stainless steel housing Greater reliability • Tank Gauges • Draft Measurement • Air Control Stations • Compressed Air Filters • USN Service KING-GAGE Marine Systems ® KING-GAGE ® LevelPRO Multiple Tank Level Processors Continuous measurement of multiple ballast and shipboard service tanks. Total volume and/or tank depth Durable corrosion proof housing Digital communications output KING-GAGE ® LiquiSeal Liquid Level Transmitter Rugged marine liquid level sensor for ballast/cargo/service tanks or draft measurement. Electronic or pneumatic output Proven air purge principle Externally mounted Tank Level Indication for the Marine and Offshore Oil/Gas Industries D-2 Circle 230 on Reader Service Card Circle 227 on Reader Service Card New LNG Containment System Gets ABS Approval Tanker Technology Left: Ocean LNG Inc. tank containment system and carrier design was awarded ABS Approval In Principle (AIP). The tank design con- sists of a cylindrical tank with spherical dished ends. The 180,000 cu. m. carrier design features five of these large 36m in diameter and 40m high cylinder tanks each holding a volume of 36,000 cu. m. of LNG. MR FEBRUARY 2005 #3 (17-24).qxd 2/2/2005 9:37 AM Page 7
