World's Largest Monohull Crane Ship To Be Outfitted At McDermott Yard

The world's largest monohull crane vessel, McDermott Marine Construction's new Derrick Barge 50, has arrived in New Orleans for final outfitting at McDermott Shipyard before she goes in service in the Gulf of Mexico.

A self-propelled dynamically positioned monohull vessel, DB 50 is designed for worldwide operation in a variety of marine construction roles. She is 495 feet long and 151 feet wide with a depth from keel to main deck of 41 feet. Four 3,000-hp electrically driven azimuthing, controllable- pitch thrusters provide propulsion, mooring assistance and full dynamic positioning. Dynamic positioning is controlled by a GEC Uni-Control Duplex DP System rated for all modes of construction work, including DP diving operations.

A GEC Tams 80 mooring system monitors position and anchor lines and has computer-assisted thruster control. She can reach speeds of 11 knots.

The ship's main revolving crane is a Clyde Model 80-262-49-33. Its components include a fully active computerized motion suppression and heel compensation system. The crane has a 344.5-foot boom with the main block at 262.5 feet. It is mounted on an 80-foot diameter tub at the centerline aft of the vessel. At full revolving, it has a rated capacity of 3,527 short tons at 82 feet. Her slewing capacity over the stern is 4,189 short tons at a 100-foot radius.

The Clyde crane has a fixed rating over the stern of 4,400 short tons at 121-foot radius.

Five 2,700-kw, 6,600-V, threephase, 60-cycle alternators powered by Allen Model S37 diesel engines provide ample electrical power to the entire vessel.

The vessel's mooring system is composed of eight 26,460-pound Delta Flipper anchors, each with 7,710 feet of 3-inch diameter 6 x 36 IWRCIPS wire rope on eight singledrum Hagglund anchor hoists. Power for the hoists is provided by four 225-kw electrohydraulic units.

The firefighting capacity of the DB 50 consists of four fire monitors located on the main crane mast.

Each monitor is capable of sending a 7,900 gpm stream of seawater to a point 500 feet away to a maximum height of 230 feet. The ability to provide such a great volume of water, coupled with the mobility supplied by the dynamic positioning system, allows the DB 50 to furnish excellent firefighting capability to the Gulf of Mexico.

For pile driving, the vessel is out- fitted with a Johnston 2,000-hp diesel- fired boiler capable of producing 69,000-pounds of steam an hour at 250 psi. The boiler capacity is sufficient to operate the largest pile driving hammers in use, including the Vulcan 6300.

Underwater hydraulic equipment includes an HBM 3000A power unit with dual 1,300-foot hoses mounted on a constant tension winch capable of accommodating a wide range of underwater hammers, including the Menck MHU 2100.

Living quarters on DB 50 are equipped to accommodate 237 people. All quarters are centrally heated and air conditioned.

Lounges, cinema, game rooms and gymnasium are provided for offduty personnel. One dining room, one cafeteria-style galley and complete laundry and hospital facilities are provided. Ample offices and a conference room are allocated for customers.

She has a deck area of 30,000 square feet and a cargo capacity of 20,000 tons.

"The DB 50 will bring some outstanding advantages for offshore work in the Gulf of Mexico," said W.L. Higgins, McDermott's vice president, North & South America and West Africa operations. "They (the advantages) include its heavylift capacity, large deck area, ability to be rapidly deployed and set up, deepwater capability, efficiency for salvaging large structures, ability to accommodate pipelaying operations, and its firefighting capability.

The DB is a vessel ideally constructed for working in the Gulf of Mexico." McDermott is leasing the ship from Lombard Leasing Ltd., which purchased the vessel from British Shipbuilders.

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