The floating dry dock, 165 x 35 meter in dimension, broke loose from its mooring at the southern quay of Oresund DryDocks premises in Landskrona Sweden on the 27th of November 2011. The dock drifted in an eastern direction towards bay of Lundåkra, due to the high sea water level occurring at that day it passed over the very shallow waters and stranded approximately 3 kilometres from its original position. The floating dock then came to a stop in a sensitive Natura 2000 area. Unconventional method Because of the very shallow water depth of 0.5 meter and the protected nature area, Koole Maritiem developed an unconventional method for re-floating. With a little help from an old friend called Archimedes, thinking out-of-the-box, actually resulted into thinking inside-the-basin. Preparations At the end of January 2012 and with the use of 200 cranemats and 175 steel beams, the Dutch company built an artificial basin with an area of approximately 28.000 m² around the dock, while at the same time three excavators were digging a 2 meter deep channel with a length of 1,8 km. When the basin was finished, a gully with a depth of 2 meter was excavated as well inside of the basin, where the dock could stay afloat. All the preparations, operated during a very cold month, were finished at the end of February. Then it was time to wake up the sleeping giant, to return home. First movement When the basin was filled with about 60 million litres of water, the dock was refloated. At that point it was repositioned with the use of winches, anchors and cranes, and pointed in the direction of the newly formed channel, just above the deep gully. Moving through the channel With an alive, floating and repositioned dock, the basin was emptied and, the water level lowered to sea level again. At this point only the weather stood in the way of returning the dock. When the wind and tidal conditions were optimal, the dock was slowly but steady moving in the direction of open sea. Returning home When the dock left the temporary channel, it was towed with the use of two tugboats and assisted by a third tugboat, back to the original location at Oresund Drydocks on the 14th of March 2012. This was a sight to be seen and a crowd of spectators were witness of this unusual transport. Operations Koole Maritiem executed these operations with the utmost precision and care, minimalizing the impact on the environment and respecting the protected nature area. The operations were finished well within the required time schedule and with the dock returned, the environment is now being restored to the original state.

• published: 03 Sep 2014
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