ABOARD THE USS KITTY HAWK -- A whistle blows an alert over the shipwide intercom: "Snoopy team, starboard bow!" Spotters with powerful binoculars rush to catch sight of whatever is approaching the aircraft carrier's safe zone: a plane? a ship? a tiny sailing dhow?
If it's hostile -- an incoming missile, an enemy warship, a suspicious boat -- the Kitty Hawk can activate its defense system of missiles, automatic cannon and machine guns within seconds.
This time, the object looming on the horizon is a friend -- the USS Abraham Lincoln, one of three American aircraft carriers and dozens of other warships crowded into the northern Persian Gulf for the war in Iraq.
The ship's radar, electronic sensors and human eyes are constantly on watch for threats among the oil tankers, fishing boats and warships crowding the Gulf. "We are locked and loaded and ready to go," said Cmdr. Bob Hahn, head of the Command Directions Center, which handles the Kitty Hawk's tactical defense.
The carrier's on-board defenses include Sea Sparrow and Rolling Airframe missiles, radar-directed Gatling guns and .50-caliber and M-60 machine guns.
But the most lethal force is the air wing -- about 75 warplanes including F/A-18 Hornet and F-14 Tomcat fighters armed with a variety of missiles and several Seahawk helicopters that can carry MK-46 anti-submarine torpedoes and Hellfire missiles.
"We can get something up in a matter of seconds" if a threat is detected, Hahn said.
The three carriers in the Gulf are sending warplanes on bombing missions over Iraq. But mostly they are providing air support for U.S. and British troops, officers say. Smaller ships have been firing cruise missiles at Iraqi targets.
Although Iraq has fired several missiles at Kuwait since the war started, the Navy doesn't consider the threat from the air to be as worrisome as that from the sea.
U.S. officials have expressed concern about small boats loaded with explosives, such as the one used in the terrorist attack that nearly sank the USS Cole in Yemen in 2000. U.S. officials blamed that attack, which killed 17 U.S. sailors, on al-Qaida.
On Friday, U.S. and British forces said they had seized two tugboats carrying 68 mines in an estuary in southern Iraq.
"I'd like to think we have kept a fairly good lid on the Iraqi navy and I would say that we are pretty well prepared for any sort of terrorist evolution as well," Capt. Thomas A. Parker, the Kitty Hawk's commander, told reporters last week.
Big merchant ships and dhows, the small, wooden boats used by fishermen and traders in the Gulf for centuries, are a common sight, sometimes passing within a few hundred yards of Navy ships.
"We are in international waters, so nobody has a right to tell anybody where to go," Hahn said. "But we do expect them to keep a safe distance. A competent and reasonable seaman would give way to an aircraft carrier."
In a dimly lighted room known as "The Pit," Cmdr. Carol Prather has her finger on the trigger of the ship's defenses.
Along with Parker, she is one of just seven people among the more than 5,000 sailors aboard the Kitty Hawk who is authorized to order the firing of its weapons. The tactical action officers get a year's special training on top of their normal Navy roles.
"It is and intense environment," said Prather, 33, from San Diego, who is also a pilot of the P-3C Orion long-range patrol plane.
The Command Directions Center, a series of rooms that include the Pit, is among the most secretive places on the ship.
Journalists who visited Sunday had to wait outside while it was "sanitized," with radar and computer screens were covered or switched to an innocuous signal. Tape recorders were banned in case they picked up radio transmissions with sensitive information, and photographs were reviewed by Hahn to make sure they didn't show sensitive equipment or data.
The center is behind a door entered with a code punched into a keypad lock. A sign on the door warns away unauthorized personnel, while a sticker above announces: "Eyes of the Hawk."
Inside, rows of cabinets stand locked with safe-style tumblers. Farther in, about a dozen people sit hunched over radar and computer screens that can display the positions of aircraft over Iraq and ships in the Gulf.
The center is the ship's key link to the outside, receiving and sending information via satellite and radio to dozens of ships and land points. Its tracking and communications systems can see the battles unfolding in Iraq and troop and ship movements elsewhere, but it is not involved in planning or coordinating them, Hahn said.
"We can see the whole world," he said. "But we're worried about the current situation, what is happening right now around the ship."
The center, and those aboard the Navy's other ships in the Gulf, carefully monitor each others' movements because of the amount of traffic.
"It's like being in a cramped room at a party," Hahn said. "But as long as you are polite and accommodating to your neighbor, it works OK."
