The tunnel elements, 135m long, 9.8m high and 18m wide, were constructed in a dock about 5km from the tunnel location at the Oude Maas and 17 km from the Dordste Kil tunnel location.

After the 14 elements had been constructed, the construction dock was flooded and the dyke removed to allow the units to be towed slowly by tugs and multicats to their locations.

A week before the operation to submerge the tunnels started, Stemat began moving its anchor pontoons equipped with winches into positions where they would not obstruct shipping. The anchor cables were positioned so that when an element arrived, it could be connected to the cables. Consultation with the waterway manager (RWS) was very important because the operations were being carried out on two of the most commercially busy rivers in Europe.

Regular shipping was stopped and as each tunnel element arrived on site, it was connected to the 57 mm winch cables. The crane barge Dina M then came alongside to hoist equipment, including the measurement tower for the survey and the access shaft, onto the top of the element, the tunnel roof. The element could then be moved to its final position.

When the current slowed to 30 cm/sec, the ballast tanks were opened and the element sunk slowly into place in a pre-made trench. Computers monitored the entire operation until completion. Stemat's ships and crew contributed to a flawless operation in which all 14 elements were sunk into position on schedule.

MJ Information No: 19527