Annual r eport 2002 Annual r eport 2002 - Boskalis
Annual r eport 2002 Annual r eport 2002 - Boskalis
Annual r eport 2002 Annual r eport 2002 - Boskalis
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Robert de Vlaming, Regional Manager<br />
<strong>Boskalis</strong> Offshore<br />
Precision dredging with high-tech equipment<br />
The fallpipe vessel Seahorse is equipped with a<br />
grab that can work at depths up to 1,000 meters<br />
below the surface. The state-of-the-art steering<br />
system means that the grab can be kept in position<br />
within tolerances of only a few centimeters.<br />
More and more often, oil and gas are being drilled for<br />
in deep waters. The Grand Banks near Newfoundland,<br />
Canada are a case in point. In order to protect the<br />
underwater oil and gas drilling installations against<br />
passing icebergs, <strong>Boskalis</strong> Offshore dredges ‘glory<br />
holes’ here. These are nine-meter-deep pits the size<br />
of a football field. They are located in the seabed at<br />
a depth of 120 meters. The new grab was specially<br />
developed for this purpose.<br />
“Development and production took more than a year,”<br />
explains Robert de Vlaming, Regional Manager for<br />
<strong>Boskalis</strong> Offshore. “A great deal of very high-grade<br />
technology was used. For example, the positioning<br />
system contains technology that is used in the<br />
aerospace technology. Nevertheless, the grab can<br />
be controlled by a single operator on the bridge.”<br />
The grab, with the remote system, weighs 80 tons<br />
and it is lifted on board by a hydraulic hoisting<br />
frame (an A frame). Furthermore, a second hoisting<br />
point was installed on the Seahorse so that the grab<br />
can be moved over the full length of the ship using<br />
a winch. And then there is the ‘umbilical cord’. This<br />
line feeds the grab with electricity, and with data in<br />
three dimensions about the position of the ship and<br />
its movements.<br />
The three links ensure that close steering of the grab<br />
remains possible, even at large depths. The active<br />
swell compensation also positions the grab with<br />
respect to the movements of the ship so that work<br />
is still possible in heavy seas.<br />
10 <strong>Annual</strong> R<strong>eport</strong> <strong>2002</strong>