ABOARD THE USS PORTLAND, JAN. 27 -- The call from the USS Portland's combat information center jarred Cmdr. James B. Cook II late last night:

"Iraqi F1 fighter inbound."

Seconds later he ordered his crew -- making their maiden voyage into the Persian Gulf -- to battle stations. The amphibious landing ship's loudspeakers blared: "General quarters! General quarters! All hands, man your battle stations!"

Crewmen poured out of racks into darkened passageways and scrambled up ladders. Some raced to their posts at 50-caliber machine guns mounted behind sandbag barriers on the starlit decks, while others darted to stations in the bowels of the ship. Cryptic orders and tracking numbers crackled through the blackness of the crowded bridge.

"This is the TAO," tactical action officer Lt. Steve Roland announced calmly over the loudspeakers. "We have an Iraqi F1 inbound, 30 miles northwest. This is precautionary."

For the officers and crew of the Portland, it was the first taste of their mission in the gulf, where the ship, based in Little Creek, Va., will serve as mother vessel to six Navy mine sweepers. Despite the threat of mines, Iranian speedboats and Silkworm missiles, it is still the Iraqi pilots many U.S. ship commanders consider the greatest potential threat.

The path of the inbound Iraqi F1 Mirage -- the same type of plane that launched two Exocet missiles at the USS Stark last May, killing 37 sailors -- had been picked up over the central gulf off the coast of Iran through a high-technology tracking network connecting the U.S. naval vessels in the waterway. The southbound fighter's track was first relayed to sister ships by the guided missile destroyer USS Chandler, officers said.

"It came to the point that it was close enough {30 miles} to make us nervous," said Cook.

"It was closing pretty fast at 400 miles per hour," said Lt. j.g. Carlos Martinez, the combat information watch officer.

At 11:35 p.m., just as many crew members were preparing for the midnight watch change, Cook ordered the tactical action officer to sound general quarters.

Another U.S. warship made radio contact with the Iraqi pilot and the pilot responded via radio, Cook said.

Seconds after the initial alert, the ship's combat information center reported that the jet had turned northward and was moving away from the northbound convoy of two American warships and a chartered American military supply ship.

Commercial shipping officials reported that an F1 fighter fired one Exocet missile into the hull of the 228,688-ton Iranian-leased tanker Coral Cape in the northern gulf at about 1:35 a.m. today. The Cypriot tanker was traveling south from Iran's Kharg Island terminal, officials said.

Iraqi officials also said one of their fighters struck a second "large naval target" -- their term for a tanker -- in the northern gulf at 10:07 a.m. today, but the report was not confirmed by shipping authorities. It was the fourth attack reported by Iraq against Iranian naval targets in the past three days.

U.S. military officials said they could not determine whether the fighter they had tracked was associated with either of the attacks.

Cook said his crew's two months of training for the gulf operation paid off. They responded quickly and quietly, pulling on hoods, gloves and masks to protect against fire as they assumed battle stations. He said the ship's main defensive weapons, two Phalanx fast-firing gun systems, were ready for firing if needed.

At night, the ships involved in convoy operations here post three to four times the number of lookouts as in in most other areas of the world. A heightened alert status is the norm. Orders for general quarters are not uncommon.

Senior officers say the potential for accidental attacks concerns them the most. "We're looking for the errant, the unexpected," said Cmdr. John J. Kieley, captain of the guided missile frigate USS Reuben James, as it escorted the reflagged tanker Middletown south toward the Strait of Hormuz earlier in the day. "We're looking for the needle in the haystack."

Another senior officer was more blunt: "Our biggest fear is being sucker-punched like the Stark. She paid a price, but she helped the rest of us."

When the firefighters of the Reuben James conducted a practice drill simulating a fire in the engine room during the convoy this week, they were outfitted with more efficient and modern equipment than their counterparts on the Stark, thanks to $38 million appropriated by Congress after the incident.

Sailors on many Navy ships, particularly those assigned to the gulf, have been outfitted with new Kevlar helmets used by professional firefighters and with thick yellow fire-resistant suits, as well as with infrared thermal devices to detect hidden flames.