Thanks," I manage. I crawl out of bed and fumble for a light switch in the near total darkness of my cabin. The clock says its 6:30 AM--it would be 4:30 AM without those two abrupt time changes. I throw on some clothes, rush to the galley and grab a cup of coffee and climb up the two long flights of stairs to the bridge deck.
I'm nearly blinded when I walk onto the bridge; a brilliant morning sun streams through the row of windows. The sea is an unbroken blue stretching to a perfectly round horizon. Another perfect day. Somewhere way down there is a little hole in the seafloor, I think. Captain Ed Oonk nods cheerfully from behind the control console.
The captain points to one of the many computer displays on the bridge. This one looks very like a video game. Against a blue background, a tiny icon of a ship is inching toward a red spot near the bottom of the screen. But this is real. I'm looking at an image generated by the satellite-based Global Positioning System; the ship is us and the spot is the coordinates of our destination, Hole 395A.
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CAPTAIN OONK |
Oonk slows the ship to a crawl as we approach the icon. At his signal, a small, torpedo-shaped object about three feet long is dropped over the side at precisely 7AM, our estimated time of arrival.. This is an acoustic beacon that will be used by the ship's Dynamic Positioning System (DPS) to keep the Resolution nearly motionless for the next five days. It emits clicking sounds that will be picked up by hydrophones on the underside of the ship. These signals will provide more accurate positioning than the GPS system. But switching to the DPS won't occur for nearly an hour--the time it will take the beacon to sink the nearly three miles to the bottom.
Even before the Resolution is precisely positioned, it becomes a beehive of activity. The DPS system controls the ship by selectively activating an array of 12 "thusters" that protrude through the bottom of the ship. Each has two fixed propellers that are aimed in various directions so the ship can be pushed sideways, forward or backward under the power of 750 horsepower electric motors. In operation, the ship literally "sails" in one spot, compensating for wind, current, and waves.
One set of thrusters is fixed to the bottom of the hull. The others are in cylindrical "pods" that are retracted when the ship is underway to reduce drag (there is plenty enough drag from the derrick, which acts like a huge sail, and from the turbulence in the open "moon pool." These pods, which looked like large tanks when we were underway, are lowered. until their tops are at the same height as the decks.
Meanwhile, on the rig drilling floor, the roughnecks and drillers have begun the long task of dropping a continuous string of 5 in. steel pipe that will run from the ship to the ocean floor--and hopefully beyond into Hole 395A. Back there, its a different world: the Oil Patch. Ninety foot lengths of pipe are rolled off a rack and dragged along until the end protrudes over the opening in the deck through which the pipe is lowered. A collar-like fitting is snapped around the end of the pipe and attached to a cable. A winch grinds into action and the pipe is lifted upright high into the derrick.
The lower end of the pipe swings precisely over the upper end of the last length of pipe. which protrudes about three feet above the drilling floor. The collars are too big to fit through the opening in the floor, so the support all the weight of the pipe lowered so far until a new section is added. The length of new pipe is threaded to the preceding one and the collar snapped open and removed. Then the winch lowers the pipe until the collar on the new pipe is resting on the deck. The process will be repeated over and over until the pipe reaches the seafloor--a job estimated to take about seven hours.
With the beacon finally on the bottom, Captain Oonk slides the engine telegraphs to "Stop". Until we depart the site, control of the ship shifts from the bridge to the computers crammed into a small room above the bridge, known as the DP shack.
Oonk can now relax a bit so he makes himself a cup of tea. He is hardly a stereotype uniformed captain. He often wears chinos, short sleeved white shirts and open sandals with socks. He is also frequently seen in one of the blue Schlumberger jumpsuits. Oonk is well over six feet, broad shouldered, with piercing blue eyes. Even when he is relaxed and joking, there is no question of who is the master of this vessel.
Oonk has been at sea since he graduated from a maritime academy in his native Holland in 1962. He became a captain in 1975 and was aboard Sedco 445 during experiments with mining manganese nodules from the seabed. He has been with the Resolution since it was converted into a research ship in 1985. Like the rest of the crew he works for two months and then gets two months off. A complete duplicate crew runs the ship during those times.
Two years ago, Oonk was barely able to save his ship when it was battered by 60 ft. seas in the North Atlantic. .One monster wave broke the windows on the bridge, flooding it and knocking out communications and navigation equipment. Resolution finally limped into Halifax, Nova Scotia. He goes to his cabin and comes back with a 1995 issue of Scientific American with an article describing the incident.
There is one more thing I want to know: What about these time changes? The Captain says he sets the clocks so the time of sunrise remains relatively constant. Well, okay. The ship runs on Greenwich Mean Time anyway.
While we have been talking, length after length of pipe has been added to the rapidly descending drill string. About halfway though, it is time to begin lowering the equipment that will be our eyes on the seabed. This boxy frame, called a Vibration Isolated Television Frame, is equipped with lights, a sensitive TV camera, and sonar. It is latched around the drill string and lowered down by an armored cable that carries power for the equipment and transmits signals to the ship where they are displaced on closed circuit monitors.
The idea is that the VIT, as its known, will end its journey down the still-growing pipe close to the time the drill string reaches bottom. Soon the TV monitors on the ship switch from views of the drilling floor to an image of the end of the pipe against a flat gray background.
At 3:30, with the camera in place, the drill string "taps" the bottom at a depth of 4455 meters (14,000 ft). The string is then raised to keep it from dragging on the bottom The camera reveals a barren landscape of gray mud. There is life here though. The resolution is not very good but things that look like black blobs crawl the bottom and small pale white fish occasionally flit through the lights.
What is not here is the borehole. When it was drilled in 1975, the hole was covered with a large funnel called a reentry cone. These large metal objects do double duty. They guide the drill string smoothly into the hole if the site is revisited and they strongly reflect sonar so the hole can be located.
The search for Hole 395A takes place in the DP shack. Three key displays are in the bank of monitors and readouts above the console that controls the motion of the ship. One shows the ship's GPS position against a square grid. The very center of the grid marks the coordinate that the ship used to find the site. Like the display on the bridge, Resolution is shown as a boat shaped icon. Other monitors show the bottom as seen by the television camera. Last is the sonar display.
Electrical supervisor "Boots" Dagg sits at the console. He begins a slow pattern of searching the grid, quadrant by quadrant. This, of course is done by slowly moving the ship several miles above. It's a painstaking exercise in delayed reaction. The movement of the ship has to transferred to the end of the pipe string far below. It takes a while to catch up. Too abrupt a motion and the pipe will begin swinging like a pendulum.
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REENTRY |
For nearly two hours, he creeps the ship across the grid. The camera shows gray mud; the sonar scans do not indicate any telltale reflection. Excitement rises for a minute when what looks like the edge of circular object appears. It turns out to be a piece of cable lying on the bottom. Occasionally the image is blurred by what look like subsea dust storms. Its probably sediment being stirred up by currents.
There is speculation that the coordinates are wrong. After all, when the hole was drilled in 1975 there was no GPS system. When a French team came calling in 1989 they used a manned submersible so they were not as dependent on the accuracy of the initial location.
We are. Both the camera and sonar reveal a small portion of the sea bed. What we are trying to accomplish is akin to searching for a penny on a 9 by 12 rug, if all you could see at one time is a spot the area of a quarter.
Ray Frank, the DP operator, sits in front of the sonar display. Suddenly a cluster of bright reflections appears at the edge of the display. "That's got to be it, " he says. Sure enough, when the scanner comes around again the bright dots are still there. Dagg begins a painstaking process of maneuvering the end of the pipe toward the reflection. Finally an object comes into view. Its the reentry cone.
After more careful adjustments in the ship's position the pipe hangs directly over the center of the funnel. The signal is given for the driller to lower the pipe. It slides smoothly into the borehole. "Well, that only took two and a half hours," says Dagg.
And yes, the GPS coordinates were wrong. The hole is 320 feet Northeast of where it was supposed to be. On land, that's stones throw. Looking down several miles of pipe, it can be a very long way. To set the record straight, here are the new coordinates: Hole 395A is located at 22 deg.; 45.3517 N. latitude and 46 deg. 04.8492 min. W longitude.
