Ocean Monster Shows Hidden Depths
Filed under: Discovery,News & Resources,Scientific Ocean Drilling
The Chikyu carries the tallest ship-borne rig in the world.
Environment correspondent, BBC News, Japan
For a while during its design, Asahiko Taira told me, the ship became known as “Godzilla-maru”, so unusual and top-heavy were its projected lines.
“We started planning the Chikyu about 15 years ago, and there were some people who thought we were too ambitious,” he recalled.
“But now we can see that the ship is doing what it is designed to do and is opening up new possibilities.”
As director-general of the Center for Deep Earth Exploration (CDex), an arm of Japan’s Agency for Marine-Earth Science and Technology (Jamstec), Dr Taira played a key role in steering the Chikyu from vague concept to steel reality.
The idea was simple. Scientists wanted to drill down into the Earth’s crust – and even through the crust – to get samples from the key zones 6 or 7km down where earthquakes and lots of other interesting geological processes begin; but that was impossible with existing ships.
Solution: find six hundred million dollars, and design and build a new one.
The first thing that strikes you when the Chikyu comes into view is the drill derrick, which stands 100m above the deck – the tallest ship-borne rig in the world.
Festooned from it are cables a handspan thick, and huge pieces of yellow machinery, all connected with the core business of sending a drill bit deeper into the Earth than has ever been done at sea.
“There is far more to drilling a hole in the ground than just drilling a hole in the ground,” Steve Krukowski tells me as we look down from the deck outside the ship’s onboard laboratory, home of the scientists waiting for the samples that the drillers will provide.
“In days gone by, rigs were manual, whereby you had a guy stuck up on the derrick running the drill pipe on a rope. All the rigs coming out nowadays are automatic, reducing the interface between man and machine.”
Steve is the Chikyu’s offshore installation manager, and runs the entire operation when the ship is stationary and drilling.
Although men are still needed on the drill floor, most of the heavy work is done by programmed machines that extract and replace lengths of the drill shaft – or “drillstring” as the professionals call it – or that screw lengths of pipe together, or bring lengths of casing that will line the drill hole.
A robot submarine is deployed near the sea floor, monitoring the shaft as it goes into the ground.
