The IJmuiden locks form the connection between the North Sea Canal and the North Sea at IJmuiden. The lock complex consists of the Zuidersluis from 1876, the Middensluis from 1896, the Noordersluis from 1929, the Spuisluis from 1940, and the Gemaal from 1975. To the west of the locks is the Fort Island, part of the Defense Line of Amsterdam. In 1859, the Water Management Board came up with a plan to make the large lock 140 meters long, 18 meters wide and 7.75 meters deep and the small lock 70 meters, 12 meters and 5 meters. Most ships of that time could pass the large lock without much problem. In 1868 the length of the large lock was reduced to 120 meters. Excavation work was completed in the spring of 1871 and the locks in the fall of 1872. The walls of the lock were brick, the floodgates of wrought iron and the ebony doors of pinewood. After the official opening, it soon became clear that the Zuidersluis was too tight. Ships of 150 meters and longer came into service and they did not fit in the lock. The pumping station on the other side of the canal, near Schellingwoude, also failed. During the discharge, the two locks could not be used for shipping, which reduced the capacity even more. In 1885, less than 10 years after its opening, a first design for a third, larger lock was submitted. This lock would be 205 meters long, 25 meters wide and 8.50 meters below NAP. On May 31, 1887, the government approved the construction and, learning from the first experience, it was decided to increase the length to 225 meters and the depth to 10 meters.
The Middensluis too soon no longer met the requirements of modern shipping, with increasingly larger ships. From 1909 onwards, solutions were sought for sailing to Amsterdamfor larger ships and in 1921 it was decided to build the Noordersluis, which was completed in 1928. This was – again – the largest lock in the world with dimensions of 400 meters long, 50 meters wide and 15 meters deep. The outer front of this lock was again located 680 meters further inland, in order not to hinder access to the harbor of the Hoogovens. A new access channel was dug in order to get large ships from the sea in front of the lock without much hindrance; the fort was thus placed on an island. The lock was closed with three roller doors, each 53.5 meters long, 7.3 meters wide and 20 meters high. Due to the high total weight of approximately 1,175 tons, the doors were transported by sea to IJmuiden from Rotterdamdragged. The first door arrived there in 1927. On April 29, 1930 the lock was officially opened by Queen Wilhelmina. It was not until 1960 that the lock could be used optimally after the North Sea Canal had been deepened and widened.
In June 2012, Minister Melanie Schultz van Haegen of Infrastructure and the Environment announced that the investigation into the new lock had been completed and that it was affordable and adaptable. The new sea lock will be located between the existing Noordersluis and the Middensluis and will be fitted with traditional straight roller doors. The top of the Velserver traffic tunnel at the deepest point of the vertical route is located at 17.34 meters below NAP and that of the railway tunnel at 16.38 meters below NAP. The new lock will be approximately 18 meters deep. The maximum draft on the North Sea Canaland in the locks is 13.72 meters. By making the new sea lock deeper than the Noordersluis, shipping will have less or no problems with low water, which will reduce waiting time. Completion was postponed from 2016 to 2019 and to 2022, but trial runs will probably be possible in 2021. After this new lock has been taken into use, the Noordersluis will be decommissioned and possibly used for maintenance and calamities. When the new sea lock is ready, it will be the largest sea lock in the world.
The new sea lock in Ijmuiden filmed from above