Nauerna sluice gate

Since the 17th century, the hamlet of Nauerna has been home to one of the most important locks in North Holland, known as the Nauernasche or Schermersluis. For centuries, it played a crucial role in the drainage and shipping of North Holland. This lock was the work of one of the most famous lock builders of the 17th century and takes its name from the reclamation project that commissioned it, the Schermer.

Aerial photo of the Schermersluis in Nauerna. Photo: Levi Borensztajn

The Schermersluis was part of the waterworks that were necessary when the Schermermeer was drained in 1633-1635. As a result, the so-called Schermerboezem lost 6349 hectares of water storage capacity. The reservoir manager, the Hoogheemraadschap van de Uitwaterende Sluizen (Water Board of the Drainage Locks), therefore demanded that wider drainage channels be constructed, to the Zuiderzee in the north and to the IJ in the south. To save costs, the Twisch watercourse, which ran between Assendelft and Westzaan, was further excavated to the north and widened into a canal. This canal carried the excess water from the Schermer ring canal near the hamlet of Nauerna into the IJ.

Map of the Schermeer, Lange Meer, Starnmeer, and Twisch, created in 1633 by surveyor Pieter Wils (c. 1600-1647). A possible extension of the Twisch to the Nauernase canal is already indicated. Collection: North Holland Archives, Image collection of the municipality of Haarlem 51989

The city of Alkmaar had a major interest in the reclamation of the Schermer and therefore took the initiative for this project. Many smaller and larger lakes around the city had already been drained, and the polder farmers preferred to sell their products at the markets of the nearest city. Purmerend benefited greatly from the reclaimed Beemster, and Alkmaar expected the same from a reclaimed Schermer.

The reclaimed and parceled Schermer in 1635 (north is on the left). The Heerhugowaard was reclaimed in 1629-1631, the Beemster in 1607-1612. The Schermer was the last of the large lakes in North Holland to be reclaimed. The smaller 'Ster Meer' or Starnmeer would follow in 1645. Only the Lange Meer remained. Collection: Rijksmuseum, RP-P-AO-9A-43-1

At the end of the canal, a large lock was built in the sea dike along the IJ. This not only served to drain excess water, but was also important for shipping traffic. The lock was designed by Willem Jansz Benning (1569/70-1636), an innkeeper and lock builder living in Alkmaar, who was a contemporary of the famous Jan Adriaensz Leeghwater. Benning was first a lock keeper in Edam and later a designer of locks at home and abroad. In Zijpe, he rebuilt the Grote of Oudesluis in 1631. The Schermersluis was built between 1633 and 1634, modeled on this sea lock.

The doors of the Schermersluis lock are closing. In the left door, just below the waterline, you can see the sluice gate, the slide that allows water to be let in and out to fill and empty the lock chamber when ships are passing through. Photo: Henk Looijesteijn

The Alkmaar city council hoped that the new lock and drainage canal would also open up a new trade route, similar to the North Holland Canal. However, Haarlem and Amsterdam opposed this, fearing for their trade. The land reclamation workers of the Schermeer were obliged to close the lock with a beam to prevent ships with fixed masts from passing through, forcing them to continue sailing via the Zuiderzee. Amsterdam and Haarlem kept a wary eye on the lock, which was thus 'covered'. When it became apparent in 1654 that the beam had been raised, they insisted that it be returned to its original height.

If it had been up to the city of Alkmaar, it would have had direct connections to the IJ and the Zuiderzee since 1634. Ultimately, Alkmaar had to wait another 190 years for the North Holland Canal to be built. Map by Diederik Aten, Als het gewelt comt, p. 75

The beam laid across the lock chamber was only removed shortly after 1800. Amsterdam and Haarlem were no longer able to prevent this due to political changes. The lock was so outdated that it was almost completely renovated in 1800, after the Schermer polder board had scraped together enough money with great difficulty. Two simple memorial stones in the lock, renovated in 1940, commemorate those who carried out the work and the administrators of the time. Once the lock was completed, the water board administrators were able to sail through it for the first time without having to lower their masts.

The memorial stones from 1800, unfortunately difficult to read nowadays. The large one contains the names of the water board administrators, the small one those of the executors. In the past, the lock keeper used to 'fish' for the lock fees owed by skippers with his clog, but nowadays the clog mainly serves a decorative purpose. Photo: Henk Looijesteijn

The lock was renovated several times after 1800. The current drawbridge dates from 1959. There is a capstan on both sides of the inner lock head. These open and close the lock gates. A third capstan once operated the ring. The 'guards' or 'tide guards', a kind of large floats on chains that can be lowered, prevent the lock gate from opening completely and disappearing into the gate chamber, so that when the direction of the current reverses, the lock gate will close.

Image 6: The memorial stones from 1800, unfortunately difficult to read nowadays. The large one contains the names of the water board administrators, the small one those of the executors. In the past, the lock keeper used to 'fish' for the lock fees owed by skippers with his clog; nowadays, the clog mainly serves a decorative purpose. Photo: Henk Looijesteijn

The Schermersluis has been operated by members of the local Schoone family for many years. The first lock keeper from the Schoone family was also a miller at the Pauw, an oil mill that was demolished in 1896 but rebuilt in 2017 as a hemp beater. Since 2021, the fifth generation has been working as lock keepers. Especially on summer weekends, many ships and boats are still being 'locked through' and the lock and bridge are constantly opening.

The Nauernasche Canal from the inner lock head of the Schermersluis. On the left is De Pauw windmill, and in the foreground is one of the capstans that the lock keeper used to manually open the lock gates. Photo: Henk Looijesteijn

Extra

  • The Schermersluis is located on the walking routes of, among others, the Nauernaroute and the Assendelftroute. 
  • Anyone cycling along the North Sea Canal Route will also pass over the Schermersluis lock.
  • This also applies to those cycling the Oer-IJ route. 

Schermer lock

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