The U.S. Navy’s new stealth destroyer, the Zumwalt, slipped unannounced Thursday into Portland Harbor.

In keeping with its intended mission, the warship emerged from the fog just off Cape Elizabeth shortly before 3 p.m. and caught Maine’s largest city by complete surprise.

The 610-foot ship sailed past Portland Head Light and docked at the Ocean Gateway terminal on Portland’s eastern waterfront. It was expected to leave at midnight and continue sea trials after dropping off and picking up personnel and supplies.

Annie Seuffert, 39, of Portland, was playing with her 2-year-old son, Julian, at the pebble beach at Fort Williams Park when she looked up and saw the warship. As the Zumwalt passed by Portland Head Light, a ray of afternoon sunlight poked through the overcast skies and bathed the ship in a yellow glow.

“I know it’s a boat, but what is it?” Seuffert asked.

“It’s creeping me out,” said her friend, Sara Heeley, who was at the beach with her 4-year-old daughter.

Up on Munjoy Hill, Lynne Panico, a retired engineer from Bath Iron Works, saw what looked like a cloud on the horizon. Then she realized it was the Zumwalt, which she had helped design, and ran down to the Ocean Gateway terminal to greet it.

“I came running down here on my brand new hip,” she said.

“I call it the ghost ship,” said Ernest Bowie, 79, a retired BIW electrician who lives in Portland, as he joined the small crowd near the terminal. “It’s a weird-looking thing.”

Built by Bath Iron Works, the Zumwalt cost the U.S. Treasury $4.3 billion – more than half the assessed value of all the homes and commercial buildings in Portland combined.

The Zumwalt is the first ship of a new class of high-tech destroyers. Its deckhouse is entirely enclosed atop the angular ship, which sits low in the water, like the iron-hulled steamship the USS Monitor, the first ironclad warship commissioned by the Union Navy.

UNUSUAL LOOK, ADVANCED TECHNOLOGY

For many, the ship looks like a prop for a science fiction movie. For others, the pyramid design evokes a floating temple from the Aztec empire.

The antennas, dishes and other pieces of the ship’s communication and surveillance systems are tucked away, as are the “small boats” used to ferry special operations forces ashore.

On radar, the ship looks more like a small fishing boat than a 600-foot warship.

The Navy is considering arming it with a rail gun – which forgoes the gunpowder in the shells of conventional naval guns and instead uses high-powered electromagnetic pulses along a set of rails to shoot a projectile at supersonic speeds. It maintains enough kinetic energy that it doesn’t require any kind of high-explosive payload when it reaches its target.

The Zumwalt is the Navy’s first surface warship to feature all-electric propulsion, which is powered by two gas turbines capable of generating 78 megawatts – enough electricity to light 780,000 100-watt light bulbs. That’s sufficient to handle the ship’s propulsion, weaponry and other electricity needs.

SECRET SCHEDULE, NOT FULLY NAMED

The DDG-1000 is the largest destroyer ever built for the Navy, at 15,000 tons based on the weight of the water it displaces.

With the help of two tugs, the ship docked at the Ocean Gateway in the same berth previously used by the Nova Star. A crane placed a temporary gangway between the Zumwalt and the ramp that vehicles had used to get on the ferry.

The shiphad drawn large crowds as it steamed out of Bath on Monday, and the first video images of the vessel underway have been watched by millions of people around the globe.

The Navy and BIW won’t disclose the schedule or route of the ship, citing security concerns. In 2000, terrorists bombed the USS Cole, a Navy guided-missile destroyer, while it was being refueled in the Yemeni port of Aden. Seventeen American sailors were killed.

BIW still retains possession of the Zumwalt. Once the Navy accepts possession and commissions the ship at a ceremony, it will be called the USS Zumwalt.

CORRECTION: This story was updated at 9:01 a.m. on Friday, Dec. 11 to correct the number of sailors killed aboard the USS Cole.