Photo: Dr. Jean-Paul Rodrigue, 2006.
Dredging is a complex, expensive and time consuming activity. Specialized ships, like the one on the above photo, have been built for such a purpose. Using a large suction head, the sludge is pumped into the ship until capacity. The ship then sails to the designated dumping area to release the sludge and goes back to its designated dredging area. The above ship, the “Pallieter” (launched in 2004 and owned by the DEME group, the world’s third largest dredging company) has a carrying capacity of 7,800 tons. This modern computerized dredging ship can perform very precise dredging operations with a tolerance of 0.2 meters. This is very important as dredging contracts stipulate that the contractor must remove sediments up to a specified depth. If this depth is not serviced, then the contractor is bound to redo the dredging at his own expense until the contracted depth is met. Dredging beyond the specified depth is also done at the contractor’s expense since it will not been paid for. With a crew rotation, the above ship operates 24 hours per day.