Todd To Build Santa Fe Pipelaying Vessel
Todd Shipyards Corporation and Santa Fe International Corp. jointly announced the award of a contract to Todd for the construction of the first self-propelled pipelaying reel ship. According to E.L. Shannon Jr., Santa Fe president, the vessel will cost approximately $28,000,000, including owner-furnished equipment, and it will be built at Todd's Galveston (Texas) Division for delivery in the second half of 1978.
The dynamically positioned vessel, to be named Apache, is designed to lay steel pipe from 4 to 16 inches in diameter in prewelded strings from 7 to 50 miles long. Overall length will be 389 feet 3 inches, breadth 70 feet, and the vessel will be powered by two diesel engines with 7,200 total hp, providing cruising radius of 5,000 miles.
The decision to build the ship followed more than two years of design, planning and market analysis. The Apache will incorporate some of the patented features of Santa Fe's Chickasaw, a smaller, n o n s e l f - p r o p e l l e d reel barge which, since its construction in 1970, has laid nearly 6,000 miles of oil and gas pipelines up to 12 inches in diameter.
The Apache will be able to cruise at speeds of 12.5 knots for marine pipelaying projects in any part of the world. Traveling under its own power, it will be capable of unreeling pipe off the stern at speeds of 1.5 to 2 knots.
Its reel, turning on a horizontal axis, will feed the pipe onto a vertically adjustable ramp having a built-in hydraulic pipe straightener. With the ramp raised to its maximum height, the ship can lay pipe in water as much as 2,000 feet deep for 16-inch-diameter lines and to 3,000 feet deep for smaller lines; in either case much deeper than any marine pipelines previously laid on a commercial basis. The adjustable pipe ramp also will eliminate the need for a stinger, an appendage to the lay vessel which is normally required to prevent buckling of the pipe as it descends to the seabed in deep water.
Measuring 83 feet high, the reel will have a hub diameter of 54 feet and a width of 22 feet between the outside flanges. It will carry up to 2,000 short tons of pipe, with a full load varying from 265,000 feet (50 miles) of 4-inch pipe to 140,000 feet of 6-inch, 92,000 feet of 8-inch, 60,000 feet of 12-inch, or 37,000 feet of 16-inch. The vessel also may carry any combination of these sizes on one voyage.
The Apache is designed to meet all rules and registration requirements of the U.S. Coast Guard, the American Bureau of Shipping, and the latest SOLAS (Safety of Life at Sea) conventions to qualify it for full ocean rating and to permit registry under the U.S. flag.
Capable of all-season operations in North Sea-type conditions, the vessel will be able to lay a load of pipe during a brief interval between storms in almost any ocean environment. According to design criteria, the vessel would be able to continue laying pipe while subjected to a combination roll of 5 degrees to each side, a double amplitude pitch of 5 degrees, and a total heave of 6 feet in 12-second cycles. It will be equipped with a saturation diving system to support working dives in water depths to 1,000 feet.
Four thrusters, two each at the bow and the stern, will help maintain position of the vessel during pipelaying and retrieval operations. These thrusters will be individually driven by electric motor for computer-controlled automatic positioning.
In operation, the Apache will anchor at a coastal base while pre-welded strings of pipe are wound onto the reel and joined together. When loaded, it will sail to the designated site and unreel the pipe. If more than one load is required for a job, the line will be temporarily plugged and laid on the seabed until the vessel returns with more pipe. The reeling system eliminates all offshore pipeline welding except at the tie-ins where the line connects with a previously laid string or with another installation. It also permits X-raying of the yard welds and hydrostatic testing of the pipe before the vessel leaves port.
Since much of the pipeline work is done on shore, the Apache will have quarters for only 120 persons, about half the crew on a conventional pipelaying vessel. The normal complement aboard the Apache would total 85 persons assigned to the pipelaying operation, including inspectors and customer's representatives, plus a ship's crew of 35.
Home base of the Apache while operating in the Gulf of Mexico will be at Houma, La. This is the site of Santa Fe's pipespooling yard currently used by the Chickasaw, and also is the Gulf Coast operations headquarters for the company's drilling, construction and diving organizations.