The US Navy’s efforts to create a fleet of sea drones have hit significant obstacles following a series of unsuccessful tests.

Designed to showcase the Pentagon’s autonomous drone technology, trial runs off the California coast last month concluded with crashes and software malfunctions, raising doubts about the Navy’s ability to deploy this new technology effectively.

In one incident, while officials were working to resolve a software glitch, a drone vessel collided with a stationary support boat, launching over its deck and crashing back into the water.

This event, captured in videos obtained by Reuters, involved two vessels from US defense tech firms Saronic and BlackSea Technologies.

Weeks earlier, during a separate test, a support boat captain was thrown into the water when an autonomous BlackSea drone suddenly accelerated, causing the boat to capsize. The captain was rescued but declined medical attention. This incident was initially reported by Defense Scoop.

Both incidents were attributed to a combination of software failures and human error, including breakdowns in communication between onboard systems and external autonomous software, according to a source familiar with the matter who requested anonymity to discuss sensitive information.