Self-driving tech is all the rage these days, with companies looking to , taxis and . But the tech isn’t limited to dry land, and companies around the world are looking at new ways to remove the need for crews on container ships. work that experts are undertaking to make “safe and secure” autonomous vessels to haul freight across the waves.

According to the report, a fertilizer company in Norway is working to slowly remove the crews that operate one of its 80-meter (260-foot) container ships. Currently the Yara Birkeland, which can carry up to 100 containers, operates with a crew of five on journeys along the Frier Fjord in southern Norway. But by the end of this year, the crew will be cut down to two, with aims of removing the bridge entirely over the next two years.

When that happens, the ship’s captain will be based at an on-shore operations center, where they will remotely oversee the voyages undertaken by several ships at once. There, they will be able to intervene if necessary but, on the whole, .

In order to make the vessel capable of sailing itself, the ship’s owner Yara has fitted it that scan the route it takes up the Frier Fjord. On the journey, which the Yara Birkeland makes twice a week, it collects data about the voyage, conditions and its surroundings.

Repetitive journeys like this, the BBC says, offer a perfect way to introduce autonomous ships to the system. In Norway, the BBC report uncovered this Yara voyage, as well as similar projects involving two in the Oslo Fjord, each operated by Nordic grocer Asko, and a fourth container ship that operates near Ålesund. All of these vessels use technology from autonomous vehicle expert Kongsberg.

“You can use autonomy to limit tasks that are dangerous or boring,” Marius Tannum, an Associate Professor of Applied Autonomy at the University of South-Eastern Norway, told the BBC.

“The Yara Birkeland project and the Asko barge project are pushing the technology out into the real world, and not just in research labs, like we have been doing for many years.”

Slowly, this technology is being scaled up to work on much larger vessels, including a pilot project that saw a 730-foot car ferry navigate and dock itself using autonomous technology provided by Mitsubishi Shipbuilding Company.

But while the technology continues to advance, experts the BBC spoke with warned that there’s one big hurdle autonomous ships have yet to overcome: legislation. :

“Current legislation has been developed based on the presumption that the equipment onboard a ship is fully manually controlled,” says Sinikka Hartonen, adding that the International Maritime Organization is now working towards a framework.

“The regulation is totally new territory for the marine authorities and politicians in Norway. What they do will have consequences internationally,” says Yara project manager Jon Sletten.

Once a legal framework is in place for ships to sail autonomously across the ocean, experts predict the technology will move forward at a rapid pace. The next step will be to develop “robust” propulsion systems that won’t require maintenance from crew mid-journey.

Finally, engineers will need to prove that autonomous ships “” a vessel with an on-board crew. Once that happens, the technology could become widespread much faster than self-driving cars or trucks.