BV to Class LNG Carrier

International classification society Bureau Veritas has been chosen to class the 153,500 cu m LNG carrier ordered by Gaz de France from Chantiers de l'Atlantique this week. This is the largest ever LNG carrier and is due for delivery in 2005. The order includes an option for a second vessel. BV helped develop the concepts for the vessels, and developed unique new rules to allow the yard and owners to break new technological frontiers. "BV has consistently been the world leader in LNG carriage, since development of membrane LNG carriers was first begun," says Bruno Dabouis, commercial manager of BV's marine division. "Now we will class these new vessels, which are a quantum leap forward in cost-effective LNG transportation. The innovative features in these ships will set the benchmark for the rest of the world to live up to." The ships have two key innovations. The traditional steam turbine plant will be replaced by a low-pressure dual fuel diesel electric system, and the cargo gas will be carried in the new GTT CS1 membrane system. BV co-operated with Wärtsilä for the development of the safety concept of the low-pressure dual fuel diesel/gas engine, and has issued new rules for such engines. These are unique, and set new standards for this type of machinery plant. BV also co-operated with GTT on the complex calculations and modeling needed to develop the cost-effective CS1 containment system. CS1 was granted BV concept approval in 2002. The dual fuel diesel electric propulsion system offers several advantages. As a more compact installation, it allows the shipyard to maximize cargo space in the hull. It will reduce gas consumption compared to the conventional turbine installations. Operators will have more flexibility with respect to crewing, as engineers familiar with turbine installations are now in short supply. Maintenance is simplified as generator sets can be taken off line and maintained on passage. Machinery redundancy is enhanced, cutting the risk of a power failure. The CS1 containment system combines the best features of the proven Mark III and NO96 membrane systems. It offers increased strength, faster fabrication, and a cost reduction of 15 per cent compared to existing systems. Partial loading conditions are also possible, improving operational flexibility.