The marine transport of L.N.G. on a commercial scale is now well into its third year, with three ships operating on a regular schedule between North Africa, Great Britain and France.
Three more L.N.G. tankers are now under construction in Italy for service between Libya and Italy; another, to the same design, will be built in Spain for service between Libya and Spain. A further two are expected to be constructed for shipments to Japan.
The ships in operation or under construction incorporate free-standing L.N.G. cargo tanks of aluminium or nickel steel, heavily insulated from the ship's hull; their total cost is roughly twice, but cargo deadweight only half, that of conventional oil tanks of the same dimensions.
Designers are now actively developing improvements to existing techniques and pressing ahead with their research on alternative cargo tank forms, with a view to reducing construction costs. The so-called membrane cargo tank concept provides the best hope for achieving significant savings however, the reduction in ship capital cost is unlikely to exceed fifteen per cent.
The closest attention to the maintenance of adequate safety standards and operational reliability in this rapidly developing, highly specialized and tightly integrated shipping operation, is absolutely essential. by R. C. FFOOKS, Conch Methane Services Ltd., London, Great Britain Cette communication donne un bref exposé de certaines améliorations techniques résultant de l'expérience acquise pendant la construction et après l'entrée en service des deux premiers navires pour le transport commercial du G.N.L.
On trouvera traités les problèmes posés et résolus au cours de la construction des essais à basse température, ainsi que pendant plus de deux années de service des deux navires britanniques.
On y examine aussi quelques plans et les premières phases de la construction des futurs navires pour le transport du G.N.L.
Une section est consacrée aux travaux les plus récents effectués pour rendre le transport par mer plus compétitif sur petites et grandes distances.
The marine transport of L.N.G. on a commercial scale has now entered its third year. It has got off to a good start.
Considering the complete absence of previous experience and that it was therefore necessary to develop the design technology from first principles, makes it all the more satisfying to those concerned that the first two years of commercial operation have been so successful.
That it seems to have been part of the marine world scene much longer than this is because the research leading up to it, and the technical literature published on it, now spans more than 10 years. Current research and development on new and improved designs is still intense.
Papers presented to the 5th and 6th World Petroleum Congres's, described in some detail developments leadingup to the construction ofthe "Methane Pioneer" and