Page 7: of Maritime Reporter Magazine (October 1973)

COMMISSIONING—The Pentagone 82, a semi-submersible offshore drilling rig weighing more than 10,200 tons, during the recent commissioning ceremonies at the Gulf Marine Division shipyard of Marathon Manufacturing Company, located in Brownsville, Texas.

First From Its New Shipyard

Gulf Marine Division Of Marathon

Commissions The Pentagone 82

PENTAGONE 82 COMMISSIONING OFFICIALS—On the platform at Brownsville, Texas, back row (from left), John Austin III, who issued the call to commissioning; Gene M.

Woodfin, president, chief executive officer, Marathon Manufacturing Company; Georges

Barthe, president, Forex Neptune; Jack R. Hilder, Gulf Marine Division, Marathon, and

Pierre Cordey, Forex Neptune. Front row (from left), Sylvie Langle, flower girl; Mrs.

Hilder; Mme. Barthe, ship sponsor, and Mme. Cordey.

The first offshore drilling- plat- form to 'be built at the new Gulf

Marine shipyard of Marathon

Manufacturing Company was com- missioned recently during colorful ceremonies held at this Port of

Brownsville, Texas, shipyard. The huge semisulbmersible rig, weigh- ing more than 10,200 tons, was built for Sea and Land Drilling

Contractors, Inc., who will operate it in the North Sea.

Christened, Pentagone 82, this semisulbmersible platform is a sis- ter-ship of Pentagone 81 which has operated in the North Sea for the past three years. Five other Penta- gone platforms are currently under construction throughout the world for various owners. One of these units, Pentagone 84, is destined for

Triton Industries, Inc.

This platform design has demon- strated exceptional qualities of sea- worthiness, safety and drilling sta- bility during the last unusually stormy winters in the North Sea.

Sea and Land Drilling Contract- ors, Inc., is a subsidiary of Schlum- berger who also owns Triton In- dustries, Inc. Schlumberger first extended its activities into the drill- ing industry by acquiring partial ownership of Societe Forex, a

French company specializing in drilling on land. Forex had created an offshore drilling company which was incorporated in France and named Neptune as a joint venture with another French drilling com- pany. In 1970 Schlumberger ac- quired full interest in Neptune.

Pentagone 82 is 325 feet long, 338 feet wide and has an overall height of 317 feet. The machinery and deck levels are supported on five columns, each 31 feet in di- ameter. At the base of each column is a circular pontoon 70 feet in diameter and 23 feet high. The rig has been given the classification of B4 by Lloyd's Register of Ship- ping.

When being towed, the rig will have a draft of approximately 24 feet. In the drilling position, the draft is approximately 72 feet. The unit has its own propulsion system to assist when under tow.

The Pentagone platform was de- signed by the Institut Francais du Petrole and Societe de Forages en Mer Neptune of Paris, France.

The design criteria for the drill- ing rig is for 79-foot waves with a wave period of 15^ seconds and to withstand wind speeds of 138 miles per hour. The natural pe- riods of the sea would produce a motion of a 20 second heave period and a roll and pitch period of 32.40 seconds.

The Pentagone 82 is designed to operate in water depths up to 660 feet.

The Pentagone 82

The main deck of the Pentagone 82 has an area of 25,030 square feet including the helicopter platform.

All of the accommodations and machinery spaces are located un- der the main deck on two decks which are approximately the same size.

To assist during towing opera- tions and for maneuvering while on the drilling site there are two 2,000-hp 120-inch fixed propellers, mounted in Kort nozzles, at the base of the after columns and one 750-hp 80-inch steerible propeller on the bow column. This system allows omni-directional propulsion assistance and develops a maxi- mum thrust of 68 tons in the bow- aft direction.

When in operation the rig is moored by 10 lines, two from the top of each column. Each mooring consists of a mooring winch with 660,000 pounds holding capacity, 5,000 feet of 224-inch anchor line and a 30,000 pound anchor.

Mounted at the forward end of the main deck are two cranes, each having a lifting capacity of 20,000 pounds at a 125-foot radius. Mount- ed at the top of the two after columns are auxiliary cranes with a capacity of 6,600 pounds at 100 feet.

The main power plant consists of four diesel-electric, alternating- current generator sets with S-12-

E-l-GW GM engines and G.E. AC (Continued on next page)

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