Bad weather prevented the Bly from following its intended path up the west coast of Denmark. Instead, it took a shortcut through Germany’s Kiel Canal, sailed around the Danish islands in the Baltic Sea, cruised past Copenhagen, and then sailed along the east coast of the Jutland peninsula, a path that covered the same distance as the original route.

Two mariners were on board the ship in case human intervention was needed. In addition, the Bly could be remotely controlled from Sea Machines’ Boston headquarters. The ship stayed within 11 miles of the Danish coast and stayed in touch with the company through a Danish 4G wireless network.

However, Johnson said the ship steered itself for almost the entire voyage, using radar, radio beacons, and cameras to automatically detect and avoid navigational hazards, including other ships.

At the Boston control center, the voyage was overseen by sailors belonging to the American Maritime Officers, a union representing officers working on US merchant ships. The partnership between Sea Machines and the AMO is aimed at ensuring that human sailors still will have roles to play even if seagoing craft become increasingly automated.

“We want to have an understanding of the technology, rather than read about it in a newspaper,” said T. Christian Spain, AMO’s vice president of government relations.

A typical freighter of the 1970s would have crews of around 35 people, while today’s ships are operated by about 20 people. Despite this trend, Spain predicted that seagoing ships will rely on human crews well into the future.

“Will there be less people on ships traveling the oceans once this technology matures?” said Spain. “Probably. But that’s a long way off.”

“We all recognize that this is not about robots taking jobs away,” Johnson said. “It’s about a retooling of the industry to do more and do it better, do it faster.”

Johnson said that automated cargo ships could reduce the risk of massive backlogs at US ports. Instead of building huge cargo ships that can only be offloaded at a handful of major seaports, smaller, automated ships could run frequent direct trips to smaller terminals, like those in Boston or Portland, Ore.

Read the story on Boston Globe here.