Dutch King Willen-Alexander on Wednesday opened what authorities say is the world's largest canal lock. 

The 500-meter (1,640-feet) long and 70-meter wide sluice replaces a smaller, nearly 100-year-old one at Ijmuiden, a small port city connecting the North Sea Canal to the port of Amsterdam. 

Construction on the massive infrastructure project began in 2016 and was meant to be done by 2019. It also went over the initially planned budget by around €300 million ($338 million).

'A bigger front door'

The Ijmuiden lock was designed to allow large, modern cargo ships to reach the port of Amsterdam.

"Amsterdam has just been given a bigger front door," said Jaap Zeilmaker of the Dutch waterways agency Rijkswaterstaat. 

The structure is also deep enough that ships will no longer have to wait for a favorable water level to enter the canal. 

"The new sluice will not just benefit the economy, but thanks to the technical expertise involved sea level rise and the influx of saltwater have also been taken into account," Zeilmaker added.

The older structure, Noordersluis (northern lock), was built in 1929 and had to be replaced.

Newspaper Het Parool quoted state harbormaster Milembe Mateyo as saying that several malfunctions at the Noordersluis were recorded in recent years. "It's an old beast," she said.

With almost nine meters above the sea leave, the structure is also a defense against the threat of flooding. 

Why did the project go over budget?

In 2018, then-Infrastructure Minister Cora van Nieuwenhuizen said that she had to increase the budget for the project owing to setbacks in construction. 

According to Dutch media reports, contractors BAM and VolkerWessels said there were about 200 improvements and changes to the design during the construction period.

The two construction companies blame Rijkswaterstaat for the ambitious initial design. Dutch trade magazine Cobouw reported that BAM and VolkerWessels were filing compensation claims against the waterways agency. 

Naming contest

Design flaws aside, Dutch authorities sought the people's opinions on what the world's largest canal lock should be named. 

The municipality of Velsen, where Ijmuiden is located, said it received 5,000 entries, including playful names such as "De Sluizenmoeder" (The locks' mother) and "De Irma Sluis," in reference to a sign-language interpreter who gained popularity through the government's coronavirus press conferences. 

However, the municipality settled on the name "Zeesluis" (sealock). 

"The name Zeesluis IJmuiden is exactly what it is: located in IJmuiden, the lock will be the gateway to the North Sea Canal area and the ports of Amsterdam for the next 100 years. An important lock, with a crystal-clear new name," said Nieuwenhuizen, the former infrastructure minister.

Edited by: Mark Hallam