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Mysteries of the Deep
 
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The Truth Behind Noah's Flood

3 pages: | 1 | 2 | 3 |
By Trent Schindler

The Raising of the HunleyIn "The Uncivilized Machine of War," Alan meets the archeologists who are restoring the Hunley, the Civil War submarine that carried out the first successful submarine attack on February 17, 1864. Raised in 2000, the Hunley is not the first sunken vessel to be brought to the surface. Lifting a waterlogged ship from the ocean floor is never a simple task, and each case presents its own unique set of technical challenges. Here, FRONTIERS explores the raising of some famous wrecks.
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The Kursk

On August 12, 2000, an explosion tore through the double hull of the Russian nuclear submarine Kursk, sending the boat to the bottom of the Barents Sea. All of her 118 crewmen were tragically lost in the disaster. In September of the next year the Russian government commenced an effort to raise the doomed submarine, enlisting the aid of the Dutch heavy-lifting and maritime-services companies Mammoet and Smit International.

Image of the Kursk

Using a giant saw, engineers remove the damaged bow of the Kursk before bringing her to the surface.

The Kursk presented novel difficulties for the engineers who were charged with bringing her to the surface. The submarine was to be lifted from the seafloor by the barge Giant, suspending the wreck with cables during the slow ascent. However, the explosion that sunk her had significantly damaged the forward section of the submarine, creating a hazard for the Giant and her crew. If the Kursk broke apart while dangling from the lifting cables, the recoil could have placed the Giant in considerable danger. The engineers therefore decided to remove the bow section before raising the ship - a formidable proposition, considering that she lay in 360 feet of water.

The solution was a giant saw, attached to enormous hydraulic anchors laid on the seabed on either side of the submarine's hull. Stretching between the 40-foot anchors was the saw's "blade," a chain of cylindrical drums covered with an abrasive material and draped over the forward section of the submarine. Suction pumps in the anchors created a vacuum that pulled them progressively deeper into the muddy bottom, applying tension to the saw while powerful hydraulics drew the chain back and forth. The motion of the abrasive chain slowly cut into the hull until, ten days and two chains later, the bow was separated from the rest of the ship.

Meanwhile, divers drilled twenty-six holes along the top of the hull in preparation for the next phase of the procedure. Gripper assemblies at the ends of the lifting cables were inserted in the holes and opened up like expansion bolts inside the hull, securing the ship to the cables. Once the bow was separated, the gradual ascent of the ship began, but this part of the operation was not without hurdles of its own.

If the cables had been attached rigidly to the barge, rough seas could have scuttled the lifting operation by creating uneven strain in the cables and attachments. Dangerous oscillations might have built up in the pendulous Kursk-Giant system, a potentially disastrous situation if the forces were to exceed safe limits. To avoid this possible problem, computer-controlled gas cylinders were installed on the Giant at the attachment points of the cables. This active shock-absorbing system compensated for wave action by constantly adjusting the tension in the cables, dampening any unwanted oscillations.

After a successful ascent, the Kursk was brought to a depth just below the pontoons of the Giant and secured to the barge with large clamps. The entire assembly then steamed towards drydock in Murmansk, where investigators officially determined the cause of the fatal explosion to be fuel leaking from a torpedo.
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3 pages: | 1 | 2 | 3 |


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