Giant Aluminum LNG Sphere 12 Stories High Arrives At General Dynamics Quincy Yard

A giant aluminum sphere 12 stories high and weighing 850 tons recently arrived at General Dynamics Quincy, Mass., shipyard.

The sphere's journey started on December 3, 1976, from General Dynamics sphere fabrication facility, Charleston, S.C., on the specially built barge Hercules, under tow of the 120-foot, 8,600- hp tug Sheila Moran of Moran Towing and Transportation Company, Inc. The tow traveled the 900-mile winter ocean voyage up the East Coast in four days.

The huge aluminum spherical tank, the first of its kind and size ever to be constructed and transported at sea complete as a single unit, was installed in the first of 12 liquefied natural gas (LNG) tankers being built at Quincy. Deliveries of the following spherical tanks will be at the rate of one sphere every 2y» weeks.

Each of the ships under construction at the General Dynamics Quincy shipyard will be equipped with five of the 120-foot-diameter tanks. The heavily insulated spheres will each carry 25,000 cubic meters of LNG at a temperature of minus 265 degrees Fahrenheit. The tank design and insulation is based on the Moss- Rosenberg technique.

The recently completed multimillion- dollar Charleston facility of General Dynamics can work on eight giant spheres simultaneously: six under final assembly and welding in a specially designed assembly hall, with a floor area equivalent to the size of seven football fields; one in an outside hydrostatic test fixture, and another in a separate building where an 8-inch layer of insulation is applied.

Each sphere is fabricated from over 100 formed and machined aluminum plates, weighing 41/o to 12y2 tons each. About 60 miles of precision welding is required to complete each sphere.

The fabrication of the first spherical tank was completed in September. After undergoing hydrostatic testing, the sphere was moved into the insulation building where it was rotated and covered with over 10,000 panels of polyurethane insulation and sealed with coatings of rubber and polyurethane.

Each sphere is inspected by the U.S. Coast Guard and the American Bureau of Shipping upon completion in the assembly building. The spheres then are given a hydrostatic test outside the assembly hall in a special fixture.

Seven other spheres are currently in various stages of completion at Charleston. Insulation of the second sphere has been completed, and the third has been hydrostatically tested and is being insulated.

The first of the 12 ships currently under contract at Quincy is scheduled for delivery in the second quarter of 1977. Five of the 12 will carry gas from Algeria to the United States. The other seven will be used to transport gas from Indonesia to Japan.

All of the 12 tankers will fly the U.S. flag and will be operated by American crews.

All of the LNG carriers under construction at General Dynamics Quincy are of the same design.

They have a length between perpendiculars of 897 feet, a beam of 143 feet 6 inches, and a draft of 36 feet. Design speed is 20.4 knots.

The ships are being constructed for Cryogenic Energy Transport; LNG Transport, Inc.; Liquegas Transport, Inc.; Cherokee Shipping Corporations I, II, III, IV, V, VI and VII, and LACHMAR(2).

Deliveries are scheduled from 1977 through 1980.

The barge Hercules that was constructed by General Dynamics Quincy was specially designed for this operation. It has a length of 250 feet, a beam of 100 feet, and a depth of 16 feet. It was completed last June.