“THERE SELDOM IS A SINGLE WAVE”

Roskilde, 30 kilometres west of Copenhagen, is one of Denmark’s oldest cities, founded as a trading hub in the 980s by the Viking king Harald Bluetooth. For four centuries it served as the capital of Denmark. Its Gothic cathedral, housing 39 tombs of the Danish monarchs, and the annual Roskilde Rock Festival both attract hundreds of thousands of visitors annually. As does the Viking Ship Museum housing the remains of five 11th century Viking ships, extricated from the Roskilde Fjord in the late 1960s.

The Roskilde Marina, with 370 berths, is located at the bottom end of the shallow Roskilde Fjord. In 2021, when the marina owners were looking to expand, they enlisted SF Pontona ApS to install a 30-metre-long floating breakwater and a 205-metre-long concrete pontoon dock with fingers, providing 61 additional berths. The new breakwater has its work cut out, as it is exposed to the northern fetch of Roskilde Fjord, which can produce very choppy waters. The breakwater and pontoons are anchored using pile guides to accommodate water fluctuation. During winter storms, water levels on the Fjord, connected by a narrow entrance to the Kattegat, can increase by up to two metres. Before piles were driven in, the sea floor was examined for remains from the Viking age.