IJmuiden Sea Locks

The IJmuiden Sea Locks are the gateway between the North Sea and the port of Amsterdam, and they have been described as the largest sea locks in the world. They stand at the western end of the North Sea Canal, which was cut through the dunes and the low land of North Holland in the 1870s to give Amsterdam a direct and deep route to the sea. Before the canal, ships had to cross the shallow Zuiderzee, and the city's trade was suffering. The canal and the locks at IJmuiden made Amsterdam accessible to large steamships again, and the area developed rapidly into a harbour town and a centre for fishing and steel.

The need for locks is easy to explain. The canal is held at a stable level, close to that of the land around it, while the North Sea rises and falls with the tide, so ships pass through a lock in which the water level can be raised or lowered to match. The locks also keep the salt water of the sea from flowing inland. Over the years, as ships became larger, the locks have been enlarged and rebuilt several times. A complex of older locks, known by their positions as the Zuidersluis, the Middensluis and the Noordersluis, handled the traffic for decades, and the Noordersluis, opened in 1929, was for a long time the largest lock in the world.

In 2022 a new lock opened, which is larger still. It is about five hundred metres long and seventy metres wide, and it was built to allow the biggest modern cargo ships, tankers and cruise vessels to reach Amsterdam, and to ensure that traffic could continue when one of the older locks needed maintenance. Seen from the viewing areas, the scale is remarkable. Vessels that look enormous from a distance are dwarfed by the lock gates, and the slow movement of a large ship in and out of the chamber is hypnotic. The pumping and the water management associated with the complex are also important, because the locks must prevent salt water from reaching the freshwater canal and the farmland and water supply beyond.

The area has a raw, windswept character. Long piers extend into the North Sea, beaches and dunes lie on both sides of the harbour entrance, and concrete bunkers from the Second World War are scattered in the dunes. The Sea and Harbour Museum in Velsen tells more of the story of the port, and the Forteiland, an old fort, stands near the harbour mouth. The locks are not a conventional tourist site, since they are working infrastructure, but they draw visitors who enjoy engineering and ships.

They suit engineering enthusiasts, photographers and families. Allow an hour, and check which lock is in use for the best viewing. Bring a windproof jacket.