General Dynamics Quincy shipyard, near Boston, has orders for twelve 125,000-cu m LNG tankers, representing 28% of the large ships of this type (120,000 cu m and above) now on order throughout the world. The company has reached this favourable position as a result of modernising the yard (which it took over in 1964), and state that the yard is able to obtain steel and aluminum at prices lower than elsewhere. Ship construction at Quincy is now carried out in two basins (a third has been converted to a wet dock) and in two large dry-docks, one of which can be divided for semi-tandem building if required; there is also a dry-dock for repair work. The article briefly describes the building methods and equipment used at the yard for building these 125,000-cu m LNG carriers. The Moss Rosenberg cargo-tanks, of tough aluminum alloy, are constructed at Charleston, where GD took over and rebuilt the facility when the subcontractor had to cease operations; this reorganization will delay completion of the first ship until January 1977. The tanks leave Charleston equipped and insulated ready for installation; transport to Quincy (1,000 miles away) is by barge. The article includes a brief discussion on the design and material of the tanks. Much of the article is devoted to information and discussion on the design of these General Dynamics LNG carriers, which have the following principal particulars: Length, o.a. - 285.3 m; b.p. - 273.4 m; Breadth, moulded - 43.7 m; Depth, moulded - 25 m; Displacement - 97,430 tonnes; Draught, design (0.478 cargo s.g.) - 11.02 m; Deadweight, corresponding - 64,608 tonnes; Cargo capacity (0.478 s.g.) - 58,514 tonnes; Ballast capacity (max.) - 58,920 tonnes; Propulsion - G.E. steam turbine, mcr 43,600; shp, driving a fixed-pitch screw; at 103 rpm; 2,200-hp bow thruster; Classification - ABS, A1E, ACC, AMS; Speed, trials - 20.4 knots. Each of these ships will have five cargo-tanks of equal size (without the addition of a smaller tank as in the original Moss Rosenberg arrangement). The wheelhouse is higher than normal to give a better view over the tanks. These are two cargo-pumps to each tank; with all ten operating, the ship can be discharged in about 12 hr. An inert-gas system is installed for the initial inerting of the hold spaces (and of the cargo tanks when required). Fire-fighting equipment includes an outfit of dry-powder units for LNG fires. An arched fin is fitted to improve the flow to the propeller. A number of other features of these ships are mentioned, and general-arrangement drawings are included. The first five of these ships are being built at a contract price of between $90 and $94 million each, whereas the latest contracts are for about $150 million each and include escalation terms. It is also mentioned that General Dynamics are planning a 160,000-cu m design, and are considering the possibility of Diesel propulsion, probably in a twin-screw arrangement, for large LNG carriers.

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    Engineering, Chemical and Marine Press, Limited

    33-39 Bowling Green Lane
    London EC1P 1AH,   England 
  • Publication Date: 1976-10

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  • Accession Number: 00148630
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Feb 23 1977 12:00AM