The man standing on the beach near Ras Tanura thought he was seeing things. He knew he was in Saudi Arabia and he could observe, behind him, the towers and stacks marking the Ras Tanura refinery of the Arabian American Oil Company (Aramco). But in front of him, rearing out of the sea two miles offshore, was an enormous island of steel that he could have sworn hadn't been there the day before.
He was right, of course. The island—actually a seagoing barge with enormous "legs" drawn up above its deck—hadn't been there before. During the night it had been towed into place by a single tug on the last phase of a long voyage from England and the first phase of an imaginative construction project to provide deep-water berths for the world's new mammoth oil tankers.
Twenty years ago, when the Ras Tanura refinery went "on stream," a 1,200-foot T-shaped pier at the end of a trestle and causeway poking 2,300 feet into the Arabian Gulf could easily accommodate four tankers of the size then considered standard. But as the postwar demand for petroleum rose so did the size of tankers. Soon a second pier, this one extending out 3,600 feet, was added so that berths in water 42 to 48 feet deep could be made available. But the tankers continued to grow at such a pace that the North Pier had to be extended twice, once in 1959 and again in 1964, the year when a record 404,102,618 barrels of oil (60 per cent of all Aramco's crude oil) were exported through Ras Tanura. Eventually the "T" of the North Pier stretched 2,200 feet, and provided berths for six tankers. At the same time, pumps, pipelines, storage facilities and loading arms were being continually added to both piers or improved to shorten the costly in-port or turn-around time of the ships, to enable maximum use of the 10 berths available at the two piers, and to increase safety.
But even those measures barely kept up with the spectacular increases in ship sizes of the world tanker fleet, which frequently forced Aramco to handle tankers on the kind of schedule which would be timed to complete loading at high tide so that there would be sufficient water depth to keep the ship afloat. It became evident that tankers were being built that could never be loaded at the North Pier because of their deep draft.
As far back as 1957, when the capacity of the terminal at Ras Tanura was rated at 750,000 barrels per day of crude oil and 180,000 barrels of refined products, Aramco had retained a New York firm of consulting engineers to prepare a master plan for the port. The study considered the advantages and drawbacks of buoy berths (cheap to build individually but expensive in use because of the number of them required, the long pipelines needed to connect them to the shore, and the time which would be lost because of weather and darkness), finger piers, T- and L-head piers (most expensive because of the long trestles required to reach deep water) and two-or-more-berth sea islands. But whatever you decide, the consultants told Aramco, keep in mind that by 1980 there will be a need for berths handling tankers that will be 1,200 feet long and draw 60 feet of water.
When the time came for expansion to handle Aramco's steadily increasing oil production it was decided to build a 59,150,000 "sea island" big enough to accommodate anything the shipyards of the world were either constructing or planning. It was to be designed, of course, for maximum efficiency in loading and would berth two tankers simultaneously. In one stroke it would raise the nominal capacity of crude oil shipments from the port by 500,000 barrels daily.
Once the major decision was taken, Aramco quickly implemented it with specific details. The island would be located 11 miles northeast of the existing North Pier in 85 feet of water. It would consist of a central loading platform—the enormous island that had surprised the man on shore—sitting on four legs, each six feet in diameter and each to be driven 10 feet into the bottom of the Gulf. There would be 12 dolphins, sturdy steel towers or platforms set on piles driven into the floor of the sea and connected to the central platform by 1,000 feet of six-foot-wide walkways. The four "breasting" dolphins at each side would be placed slightly outside the central platform to bear the full weight of a ship breasting them at berth. Four "mooring" dolphins, two at each side of the complex, would support the lines and mooring cables of the ship and hold it in place against the breasting dolphins. Next to the southernmost mooring dolphin, pontoon sections would tie in to form a 50-by-50-foot small-craft landing. The length of the entire loading complex, from one outer mooring dolphin to the other, was to be 1,250 feet.
With plans made, construction could and did start. And on September 23,1964, at high tide, British newsmen and television cameramen covered the unusual sideways launching of a huge barge at the Cleland Shipbuilding Company's yards at Wallsend, near Newcastle upon Tyne.
From England it was towed across the North Sea to Rotterdam in the Netherlands, where its deck was loaded with construction materials for the long haul to come. In mid-January it started the two-month trip through the North Atlantic, past Gibraltar, across the length of the Mediterranean to Port Said, through the Suez Canal, down the Red Sea, around the blunt tip of the Arabian Peninsula and up into the Arabian Gulf to Bahrain Island.
In Bahrain—at the DeLong-Hersent-Kanoo yards in Manama—the barge began its metamorphosis from a mere cargo hauler to the oil-loading platform that was to become the major portion of the sea island, with the Saudi Arab firm of Yusif bin Ahmed Kanoo of Dammam and two international contractors working on the project.
At Ras Tanura, pile driving started at the deep-water site in June, 1964. Steel components for the project—weighing 800 tons in all—were being fabricated on Bahrain. To stand up to the sea and hold the supertankers which would tie up alongside, the heavy-duty dolphins had to be extremely strong as well as flexible. The pilings, 46 in all, were driven into the sea bed 28 to 38 feet. Clusters of these pilings, topped by 20-foot-wide platforms, make up the dolphins, the eight breasting dolphins weighing 40 to 50 tons and the four massive mooring dolphins, 100 tons each. The water's depth, plus the lengths that would be buried in the sea floor and protrude above the waves, demanded piles up to 150 feet long, so even with 32- and 55-inch diameters they are bound to have some "give." In fact, the platforms were designed deliberately for a normal sway of 21 inches (much as the Empire State Building in New York City is meant to rock a little in a high wind) but could, in case of a carelessly heavy nudge from a berthing tanker, bear up to a six-foot deflection.
Its legs towering overhead, the converted barge was towed into the roadstead off Ras Tanura in the darkness of morning on August 26th, after a 161-hour trip from Bahrain. Six of the 12 dolphins were already in place. After a 13-hour wait for slack tide, the floating platform was jockeyed into position with the help of a pile-driving barge in only 45 minutes. Then, cautiously, over a three-hour period, the thick legs were jacked pneumatically down into the depths and driven into the bottom of the Gulf. Once they were embedded, the platform continued climbing up on them until its deck reached a level 28 feet above low-tide mark. What was left of the pilings was sheared off flush with the deck, while 10 feet of Monel sheeting was welded around the platform like a skirt to protect the splash zone. What had left England as a barge had been transformed into a man-made island, set permanently on the floor of the Arabian Gulf two miles off the Ras Tanura cape. In a few months the first high-floating tanker would tie up to the mooring dolphins and begin to settle into the water with its heavy cargo of crude oil from one of the prolific fields of Saudi Arabia.
The central loading platform of the "island" measures 80 by 120 feet and in what was the former hold are engines, transformer and switchgear rooms, the slops pump and tanks, cathodic protection rectifiers (to reduce electrically corrosion of the pilings) and tanks for drinking water and fire-fighting foam. Topside, a prefabricated aluminum deckhouse containing a control room, pilots' office and laboratory is located at one end. On deck also are fully air-conditioned crew's quarters with a galley, dining space and bunks, although the men will usually sleep on the platform only when weathered in. Besides this accommodation and the maze of manifold crude and bunker lines, a 60- and a 40-foot crane (handling five and 10 tons, respectively), two floodlight towers (one supporting the shade for a prayer shelter) and four 10-man inflatable rafts are squeezed onto the crowded deck.
Two Chiksan loading stations, the heart of the platform functionally speaking, complete the layout. One serves each side. Each station has three 16-inch delivery arms through which can be pumped a maximum 75,000 barrels of crude oil per hour, and a smaller bunker arm to fuel the ship. These hydraulically-operated marine loading arms are flexible enough to compensate for the difference in high and low freeboard of the vessel (a ship settles as much as 38 feet as its tanks are filled with oil), as well as the normal movement of sea swells and the eight-foot range of the tide. A Chiksan operator will likely have to develop "sea legs" much as a sailor does on his first voyage. Standing in his control tower 36 feet above the deck, over 150 feet above the sea bottom, he feels the minute sway of the platform magnified enough to make a landlubber's head swim.
Long before the floating island was anchored between its breasting dolphins, work had also commenced on the submarine oil pipelines which would feed its loading arms from the huge aluminum-painted tanks on the beach. By late September the four parallel lines were there, waiting to be connected, settling gently into the mud on the bottom of the Gulf, their temporarily sealed ends resting clear on a 40-by-50-foot steel and timber frame 14 fathoms below the island site. From a point on shore near the North Pier trestle, the lines stretch about 12,000 feet into deep water, curving smoothly over a 3,000-foot radius to the "mud mat." The three large-diameter crude lines, 30 inches across, increase to 32 inches midway to the site and back down to 30 inches before reaching the mat. The smaller bunker line has pipe of 20- and 22-inch diameters. This two-inch difference in size in both types allowed the spiral-welded pipes to be "nested" one inside the other while in transit from Japan, a cost-saving shipping technique which was pioneered in the mammoth Trans-Arabian Pipe Line project two decades ago. Once in Saudi Arabia, a Fiberglas and asphalted felt protective wrapping and a cement coating (to add weight so that the pipe would lie firmly on the sea floor) were applied at the Dammam pipeyard of a Saudi Arab contractor. The actual laying of the pipe was managed by an international contractor with offshore experience in Aramco's Safaniya field.
Later, submarine power and communication cables joined the lines on the sea bed. Riser supports to carry the pipes to the surface were built after the central loading platform was in place while the remaining six dolphins were completed. Onshore a new pump house (the largest in the Ras Tanura Terminal, with 2,875-horsepowcr motors), a high-rate crude blender and additioned tankage are being constructed as part of the terminal expansion.
The story of the construction of Sea Island No. 1 came to an end early this year when the supertanker Tokyo Man docked there and took on the first cargo. But that was only one more step in the development of Ras Tanura port as a whole. Already approval had been granted for a new phase of the project—berths three and four on a second sea island complex, 1,400 feet long, which will cost 57,000,000. A third island, with berths five and six, is also being considered as part of Aramco's expansion program. In anticipation, the northernmost mooring dolphin on the first island was built with extra specifications, and will serve as the southern dolphin for Sea Island No. 2. Eventually, a chain of islands will stretch into the Gulf in the straight line—bearing 356"—best adapted to the tides and currents off the cape.
Constant technological breakthroughs force the company's planners to keep on their toes. Sea Island No. 2, scheduled to go on stream in 1967, is designed to handle the 200,000-deadweight-ton tankers which were not predicted for construction, by 1957 engineering standards, until 1980. But it's none too soon. A 193,000-deadweight-ton giant is nearing completion in Japan right now, 15 years earlier than forecasted. And if bigger tankers are built, it's a safe bet that Aramco's new sea islands will be ready when they call.
William Tracy is a free-lance writer and photographer in Beirut.
