PORTLAND, Maine (AP) - Growing costs and vulnerability to anti-ship missiles sank the Navy's once-heralded "stealth destroyer," a highly advanced warship designed to slip close to the shore unnoticed and pummel targets with big guns.

Faced with cost estimates upward of $5 billion per ship, the Navy had no choice but to let its prized DDG-1000 Zumwalt destroyer program end after the first two ships are built, analysts said Wednesday.

Congressional investigators long had been concerned that the Navy tried to incorporate too many new technologies on an untested platform. The originally envisioned 32 ships dipped to 12 and then seven as costs grew.

"I don't think this thing was a shock because fundamentally the whole program was a big fat target for many years," said Jay Korman, defense analyst at The Avascent Group.

Sen. Susan Collins, a member of the Armed Services Committee, said Wednesday that the Navy instead plans to build nine more of its current Arleigh Burke destroyers, possibly with some added capabilities that went into the newer warship.

The DDG-1000's growing cost came as the Navy is trying to expand to a 313-ship fleet. Officially, the new ships are to cost roughly double the $1.3 billion price of a Burke destroyer. But estimates for the first two run as high as $5 billion.

Loren Thompson, a defense analyst with the Lexington Institute, said the Navy can't afford the DDG-1000 but it can't afford to stop building ships, either, if it wants to achieve its shipbuilding goals and maintain a shipbuilding infrastructure.

Another problem with the DDG-1000 design was its potential vulnerability. Bombarding the shore with guns is cheaper than using missiles, but the ship would be vulnerable to attack if it came within 100 miles of shore to use its 155-millimeter guns, Thompson said.

"The Navy should have understood a long time ago that putting a $3 billion destroyer off the coast of a hostile country so that it could use gunfire was a dangerous proposition," he said.

Finally, there was no known threat to justify the warship, experts said.

"Please tell me what this thing would do today, if it were available in Iraq or Afghanistan?" said Winslow Wheeler from the Center for Defense Information. "Talk about something that's totally out of control. This thing is a national embarrassment, that's what it is."

For years, the Zumwalt has been one of the Navy's prized programs. It has a low profile and composites in its superstructure for stealth. It also features a form of electric drive propulsion, new combat systems and a new hull form.

Displacing about 14,500 tons, the ship is 50 percent larger than a Burke destroyer but will have half the crew thanks to automated systems.

"I still believe that the ship offers capabilities that the Navy lacks and needs, but it's up to the Navy to determine its military requirement," said Collins, a Maine Republican

Maine's Bath Iron Works, a General Dynamics subsidiary, is building one of the ships. Northrop Grumman's Ingalls shipyard in Mississippi is building the other.