Every concrete building block, or caisson, weighs 22,000 tons, is 58 meters long, 28 meters wide and between 23 and 32 meters high. The concrete blocks are transported from the port of Vlissingen, where they are being built, with four powerful tugs. That happens over the Westerschelde and the North Sea up to their final location, a distance of almost 100 kilometers.
Laying the caissons is done with the greatest precision, whereby the tides and weather conditions must also be taken into account. To lower the blocks and stable to the seabed, they are filled with water. The caissons will form the contours of the future island.