Empty “ghost” ships have been reportedly cruising between the Atlantic and Pacific Oceans with no humans on board. But these uncrewed vessels aren't being commanded by a gang of undead pirates hellbent on revenge and treasure. Instead, they are the latest autonomous ships being tested out by the US military.

The Office of the Secretary of Defense Strategic Capabilities Office (SCO), together with the US Navy, has recently confirmed the success of a second long-range journey of an autonomous ship.

The uncrewed vessel, named NOMAD, traveled 8,187 kilometers (4,421 nautical miles) from the Gulf Coast, passing through the Panama Canal, to the Pacific Coast. Remarkably, 98 percent of the journey was completed in autonomous mode, free from human command except for the taxing arm of the passage through the Panama Canal. 

The vessel is part of the epically named Ghost Fleet Overlord program, which saw another autonomous vessel, RANGER, complete a similar transit in October 2020. While they’re keeping quiet on how the vessels actually work, it’s assumed they navigate using artificial intelligence (AI) and machine learning. According to the US Navy, they’re currently testing both NOMAD and RANGER in order to “mature the autonomy systems, demonstrate system reliability, and explore employment concepts for coordinated operations with manned combatants.” 

The words “autonomous vehicle” are usually associated with aerial drones and self-driving cars, but there is growing interest in the idea of autonomous ships cruising the oceans with little-to-no human input. Autonomous cargo ships, for instance, are considered by some to be the inevitable next step within maritime shipping.

There are several pros of autonomous ships. Firstly, most maritime accidents are caused by “human error” (just look at the recent blockage of the Suez Canal), so AI could prove to be a significantly safer captain compared to a human. Furthermore, the crewless ships could be built lighter, using less space for the crew, reducing fuel consumption, environmental impact, and costs. Without a crew to hold ransom, the ships may also become less attractive for pirates. 

Like any emerging technology, there have been hurdles — reliability, liability concerns, uncertain regulations, and the threat of cyberattacks — but it appears our oceans are fated to be filled with autonomous ships in the not too distant future. 

“This is happening. It’s not if, it’s when. The technologies needed to make remote and autonomous ships a reality exist," Oskar Levander, Rolls-Royce, Vice President of Innovation – Marine, said in 2016. “We will see a remote-controlled ship in commercial use by the end of the decade.”