Sperry Computerized Positioning System Permits Pipelaying In 2,000-Ft. Waters

Equipped with a unique computerized positioning system, the Saipem Castoro Sei, the world's largest pipelaying barge, began its sea trials in August off the Italian coast.

The column-stabilized, semisubmersible barge, which measures 470 by 212 by 98 feet is designed to lay pipe on the floor of the Sicilian Channel in depths to 2,000 feet—almost four times deeper than previous technology permitted. The pipeline will extend for 100 miles between Tunisia and Sicily, and will be used to supply annu ally 12,000 million cubic meters of Algerian gas to Italian customers.

To provide the extremely accurate control necessary to lay and weld the pipe, particularly where the sea bottom is irregular and where adverse weather conditions prevail, the barge is equipped with a unique positioning system from Sperry's product line of seAncor systems called the Basic Integrated Navigation, Instrumentation and Positioning System (BINIPS) designed by the Sperry Division of Sperry Rand Corporation, specifically for Saipem, S.p.A., Milan Sperry's seAncor systems rely on digital computers to integrate information from sensors and to provide command and control for the precise navigation and positioning required for offshore operations.

The BINIPS system designed for Saipem includes a special computer program and other elements particularly suited to Saipem's deepwater pipelaying requirements. All sensor information is interpreted by the computer, which automatically issues commands to thrusters and anchor winches to control the vessel's position and forward motion along a precisely defined route. The control system issues force commands to compensate for environmental factors that could throw the ship off its pre-surveyed route, make the pipe-welding operation extremely difficult, and possibly damage the pipe. One feature of the system is automatic adjustment of ballast tanks to allow for desired draft, trim, and heel under diverse operating conditions.

Jerold F. Mann, manager of the Sperry program, said that traditionally, anchor winches and thrusters have been controlled manually in pipelaying operations, but that manual control has been virtually impossible to achieve in great depths and in adverse weather. He said the Sperry system will enable accurate pipelaying to be conducted in water depths to 2,000 feet despite 59-knot winds, 2-knot currents, and 17-foot waves.

The positioning system was designed and built by Sperry at its Great Neck, Long Island, N.Y., headquarters under a $6-million contract. The Saipem Castoro Sei was built to American Bureau of Shipping and Registro Italiano classification by Italcantieri S.p.A., Arsenale Triestino San Marco, Trieste, and was delivered to Saipem S.p.A. on July 22.

Mr. Mann said the barge is expected to begin laying pipe in the Strait of Messina by the end of the year.

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