King Willem-Alexander opened the largest sea sluice in the world at IJmuiden on Wednesday afternoon, concluding a project that finished over time and over budget.

The new sluice replaces the smaller Noordersluis which was built in 1929. The construction of the new sluice, which was started in 2016 and expected to be finished in 2019, was plagued by mishaps, causing delays and rising costs.

A construction error made by builders BAM and VolkerWessels cost the companies hundreds of millions of euros to rectify.

A public contest to name the new landmark sparked hilarity online when Velsen municipality sifted through 5,000 entries before opting for the prosaic ‘Zeesluis IJmuiden’. Infrastructure minister Cora van Nieuwenhuizen said: ‘The name Zeesluis IJmuiden is exactly what it is.’

Alternative suggestions included De Irma Sluis, after the sign language interpreter who became a household name during the coronavirus press conferences, but the idea was rejected because public infrastructure projects cannot be named after living people, except for royalty.

The sluice, which is 500 metres long, 70 metres wide and 18 metres deep, has been put through its paces since the summer and is now ready to accommodate today’s ever-larger sea vessels, waterways agency Rijkswaterstaat said.

‘Amsterdam has just been given a bigger front door,’ Jaap Zeilmaker of Rijkswaterstaat said. ‘The new sluice will not just benefit the economy but thanks to the technical expertise involved sea level rise and the influx of salt water have also been taken into account.’