One of the biggest and most technologically advanced warships based at Pearl Harbor remained aground today in 17 to 22 feet of water a half-mile off Honolulu International Airport's Reef Runway.

No one was injured in the incident, which was reported around 9 last night, the Navy said.

Navy tugs tried early in the morning to nudge the 9,600-ton and 567-foot guided missile cruiser USS Port Royal off the sandy and rocky bottom, but were unsuccessful, officials said.

Crew members on the Clean Islands, an oil recovery vessel that was positioned behind the Port Royal as a precaution, said the water was so shallow they could see the bottom.

The Navy said divers from Mobile Diving and Salvage Unit One from Pearl Harbor and the salvage ship USS Salvor would try to tow the warship.

An initial attempt to free the Port Royal between 11 p.m. Thursday and high tide at 2 a.m. Friday was not successful, the Navy said.

Officials said the guided missile cruiser left port yesterday for several days of sea trials after leaving drydock about a month ago for routine maintenance. Shore-based Navy officials were being transferred to Hickam harbor by small boat when the grounding occurred, the Navy said.

Navy officials said a high tide that could float the cruiser off the bottom is expected at 2:45 a.m. tomorrow morning.

"We're certainly working on bringing to bear the resources we have to move her off the current position. We're still putting that plan together," Navy Capt. W. Scott Gureck, a spokesman for U.S. Pacific Fleet, said this morning. "Obviously, the high tide gives us an opportunity to do that."

The cause of the grounding is under investigation, but the highly-visible stranding is an embarrassment to the Navy, which does not take such incidents lightly.

"I'm not going to speculate on what happened," Gureck said.

Ship captains, who bear ultimate responsibility for the vessel under their command, are typically relieved of duty during such an investigation. Often, a grounding is a career-ender.

The Port Royal has been under the command of Capt. John Carroll since October. Carroll commanded the frigate Rodney M. Davis out of Everett, Wash., in 2002, and deployed to the Arabian Gulf as part of the Nimitz strike group in support of operations Iraqi Freedom and Enduring Freedom.

He was the reactor officer on the aircraft carrier George Washington, and more recently graduated from the Industrial College of the Armed Forces.

Officials said the crew was still aboard, along with other Navy officials, including Rear Adm. Dixon R. Smith, commander, Navy Region Hawai'i and Naval Surface Group Middle Pacific.

Gureck said state Adjutant Maj. Gen. Robert G.F. Lee and other state officials were notified of the stranding.

Lee said he was informed by the Navy that the bow of the ship was stuck on

the reef.

Asked if the Navy explained how the ship ran aground, Lee said, "Just coming

into Pearl Harbor at night and it got a little too close to the reef, is what was explained to me."

Gureck said, "We're keeping everyone informed. We're very mindful of the fact that we don't want any fuel leak if we can possibly avoid it."

He added this morning that, "So, far, there's no leak that we're aware of."

Coast Guard Lt. John Titchen said the grounding was being monitored, and three overflights had been made as of this morning in HH-65 Dolphin helicopters.

The Navy has jurisdiction over the stranding because it involves a Navy vessel and because it took place in the channel leading to Pearl Harbor, Titchen said.

Titchen said there was no oil sheen that would indicate an oil spill.

"We know that there is no oil spill at this point, and we're confident the Navy is doing everything it can," he said.

It was unclear today when the last Navy ship grounding occurred off Hawai'i's shores.

In July, the skipper of the San Diego-based amphibious landing ship Pearl Harbor was relieved of command after the ship ran aground in the Persian Gulf, the San Diego Union-Tribune reported.

The newspaper said Cmdr. Xavier Valverde had been reassigned to the staff of the Naval Forces Central Command in Bahrain while the incident was investigated.

Commissioned in 1994 and costing $1 billion, the Port Royal has a crew of about 360.

The Port Royal is one of three cruisers home ported at Pearl Harbor, along with six destroyers, two frigates and about 15 Los Angeles-class nuclear attack submarines.

Officials said there could be damage to the Port Royal's sonar dome, which is encased in an eight-inch thick rubber housing protruding under the front of the bow.

There also could be damage to the shaft and propeller and twin sets of struts that stabilize them at the stern. If there is serious damage, repairs could take up to six months, including the possible need to find a replacement rubber sonar housing for a cruiser, officials said.

Port Royal is the 27th and final Ticonderoga-class cruiser, and has been retrofitted with theater ballistic missile shoot-down capability.