A cutting-edge unmanned ship designed to hunt submarines was docked just south of the Tilikum Crossing on Thursday.

The Anti-Submarine Warfare Continuous Trail Unmanned Vessel, or ACTUV, is designed to track stealthy diesel electric submarines and operate without any onboard crew. The prototype is called Sea Hunter.

A project of the Defense Advanced Research Projects Agency, or DARPA, the vessel was developed with the Portland-based Vigor Industrial. The company in 2014 acquired Oregon Iron Works, a Clackamas manufacturer that's previously worked on secretive military vessels.

A Vigor spokesman said the company can't discuss the project. DARPA has said it's preparing to test the ship at sea this spring.

It says the ship is designed to operate at long range for months at the time, possibly without intervention from any humans. That could include, as DARPA puts it, "autonomous interactions with an intelligent adversary."

The ship is docked at Portland Spirit River Cruises. The company's owner, Dan Yates, said the ship would be christened there next month before it heads out to sea.

-- Elliot Njus

enjus@oregonian.com

503-294-5034

@enjus