BATH, Maine — The future USS Zumwalt and a crew of about 150 sailors will navigate the Kennebec River for the last time Wednesday afternoon as the first-in-class DDG 1000 leaves Bath Iron Works headed for training operations, commissioning in Baltimore and, eventually, a new homeport of San Diego.

At a cost of more than $4 billion, the “stealth” destroyer is the largest ever built by the Navy, at more than 610 feet long and 81 feet across. It boasts a flight deck nearly twice the size of the Navy’s Arleigh Burke-class destroyers, which the Zumwalt line was designed to replace until cost overruns spurred the Navy to end the line after three vessels.

Capt. James A. Kirk, who commands the vessel, wrote in a March 2016 U.S. Naval Institute article, that the new destroyer can carry two MH-60R helicopters.

The three destroyers, which cost an estimated $22 billion in total, are designed to deflect radar and provide missile and gun support for troops ashore.

The Zumwalt features new technologies, including a multifunction radar system designed to allow the ship to get closer to land without being detected, two advanced gun systems that fire Long-Range Land Attack Projectiles that can reach up to 63 nautical miles, an integrated undersea/anti-submarine warfare detection system and a vertical launching system.

Perhaps more importantly, the Zumwalt’s integrated electric power will allow the Navy to add advanced air missiles, radars, rail guns, lasers and other advanced tools that will be important as the combat environment — and potential threats — evolve, Navy spokesman Lt. Robert Myers said previously.

Once in San Diego, the Zumwalt will undergo mission systems activation and “post-delivery availability,” according to the release.

Kirk wrote that additional equipment would be installed after the destroyer reaches San Diego, and additional testing will take place at sea in 2017.

Named for Elmo “Bud” Zumwalt Jr., chief of naval operations from 1970 to 1974, the DDG 1000 was christened at BIW in April 2014.

Bruce Gagnon of Bath will not celebrate the ship’s sail-off on Wednesday afternoon. Instead, he and 11 others — the “Zumwalt 12” — will appear in West Bath District Court to face charges stemming from a June 18 protest that disrupted the June 2016 christening of the second Zumwalt destroyer, the future USS Michael Monsoor.

Twelve people, including Gagnon, were arrested outside the Bath shipyard after blocking traffic in front of the yard’s south gate, police said at the time.

“It’s a sad day because it means that the Zumwalt will be that much closer to heading into the Asia-Pacific where its job is not to defend the U.S., but to sneak up on China and blast them with the new electromagnetic rail guns,” Gagnon said Tuesday in an email. “It’s a forward deployed attack warship.”

On Aug. 2, all 12 pleaded not guilty to the misdemeanor charge of obstructing a public way.

Gagnon said Tuesday they would each “take it to trial.”

“We don’t think it is a crime to try to stop the ‘christening’ of a destroyer that will help usher in World War III,” Gagnon said.