(Above and Right): Strandjacks (individually controlled by computers) mounted on the tops of turrets are attached to chains (two per turret or a total of 24 chains) that pass under the hull and are fi xed to the port side of the wreck. This holdback system will be used for balancing purposes during the rotation and parbuckling of the wreck.
parbuckles, and will involve 60 strand jacks to tighten a series of cables that will be used to pull the wreck into an upright position.
Refl oating Sponsons, Part Two: An additional 15 sponsons will be attached to the starboard side of the wreck, along with the last 4 sponsons onto the portside, for use in the refl oating stage.
Refl oating: With the hull resting on the false bottom, water will be drained from the sponsons via a pneumatic system and the refl oating will commence.
It’s during the parbuckling stage—which is the most delicate and perhaps the most critical—that wire rope will play a pivotal role. “T ere are 36 strandjack wire bundles/machines, and each wire bundle has 18 x 19-millimeter smaller wires as a part of the bundle,” Sloane explains. “T ese are all fi tted from the off shore side of the fl otation sponsons to the outboard side of the platforms. T ere are also 24 strandjack wire bundles/machines that pull the hold- back chains underneath the Concordia, adding to the rotational forces. T ese are made up of 5 1/4-inch chain, into Dyneema Ropes (of 128-millimeter diameter), and then connected to the strandjacks themselves.” Given the placement of the cables on the side of the vessel, the installation must be performed slowly and carefully to ensure the utmost precision. “Once the fl otation sponsons have been welded onto the side
of the Concordia, the strandjacks are fi tted,” he continues. “First the strandjacks are fi tted to the top of the sponsons, then each individual ‘bitter end’ of the strand-bundles of wire, are moved off shore and attached to the outside of the platforms, onto pre-installed ‘Delta- plates.’ T e middle nine sponsons shall each have four strandjacks fi tted. T is process shall be extremely slow, as the length and weight of the wires/strandjacks and the distance and height between the
20 MARCH-APRIL 2013 WIRE ROPE EXCHANGE
Photos courtesy of project partners Costa Crociere and Titan Micoperi
connection points shall be challenging. We hope to be able to fi t four strandjacks per day.”
Each of the 36 cables being used is rated at 500 tons, but will be limited to 350 tons for the operation, according to Sloane. Each wire-rope bundle is 120 meters long, allowing for wire-slack in the system. T e off shore rotational forces will total 12,000 tons. Inshore, the 24 wire-rope/chain systems are characterized as 5 1/4-inch chain at 50 meters in length, with 50 meters of the 128-millimeter Dyneema ropes into 16-meter x 130-millimeter wire grommets connected into the 36-meter strandjack wire rope bundles. T ese strandjacks are more powerful, Sloane points out: each strandjack is rated at 750 tons but will be limited to 500-ton pull for the operation. T e total inshore rotational forces are also12,000 tons. T ese cables/ Dyneema/ Chain systems have been chosen
specifi cally for parbuckling the Costa Concordia, Sloane notes. “Each strandjack machine is able to measure the load and adjust
the forces on each individual wire in the wire-rope bundles. T is allows fi nite control of the whole system through computer programming and allows for the loads to be adjusted as the Concordia rolls over,” he says. “Because we expect there to be a lot of minor structural failure of the Concordia herself, there shall be ‘minor shock-loads’ to the systems—the 50% additional margins on strandjack capability shall allow for these shock-loads to be accommodated.” T e maintenance of the cables poses little to no challenge, since all of the wire ropes and chain components will be brand-new and installed just before the fi nal phase. T eir exposure to seawater will be a month to six weeks at most. “T e pulling capability of the strandjacks machines can allow for
some oxidation of the individual wires to occur, without compromising the systems, but the electronics do not like sea-water ” he concludes. If all goes according to plan, the Costa Concordia will embark on its
fi nal voyage by the end of this summer—thanks, in large part, to the reliable applications of wire rope, chain and synthetic marine lines that allow for this innovative approach of historic proportions. ❙ For more information, please visit
theparbucklingproject.com.
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