HOISTING THE COLORS. Navy deploys powerful convoy as Gulf tanker escorts begin

The United States Navy fleet now on escort duty in the Persian Gulf has enough muscle to scare off any straightforward military attack, Pentagon-based officers believe. Sabotage or suicide-terrorist strikes cannot be ruled out, however. In any case, a perfect defense in military operations can never be guaranteed.

``It's a dangerous business,'' noted Vice-Adm. Joseph Metcalf III, deputy chief of naval operations for surface warfare, in a recent interview.

Two Kuwaiti oil tankers, the Bridgeton and the Gas Prince (formerly the Al-Rekkah and Gas Al-Minagish), hoisted US flags yesterday as a small group of reporters flown out by the Pentagon watched. The tankers were expected to enter the Persian Gulf by early today as they begin a 2-day trip to Kuwaiti oil terminals in the northern Gulf. It is likely they will be escorted by three US warships - the cruiser Fox, the destroyer Kidd, and the frigate Crommelin - that have been moored near them in the Gulf of Oman south of the Strait of Hormuz.

The Fox and the Kidd are two of the Navy's prize ships, both more capable than the frigate Stark, which was struck by Iraqi Exocet missiles in May. They form the core of the current US Gulf force, and will work with the force's other types of warships to maximize the effectiveness of weapons and sensors.

Nine US warships have gathered to take part in actual escort operations. Four are frigates of the Oliver Hazard Perry class, similar to the Stark. Three are cruisers: the Leahy-class USS Reeves and USS Worden, and the older Fox. One, the Kidd, is a heavily armed guided-missile destroyer originally built for the Shah of Iran. The last is the LaSalle, the command ship of the US Middle East force. The battleship Missouri and its escorts are expected to arrive in the area and add to the flotilla's strength later in the summer.

When Navy ships pass through the narrow Strait of Hormuz into the Gulf, they will likely be covered by jets from the nearby aircraft carrier Constellation. Fighters will provide defense against attack from other planes and small ships; ground attack jets such as the A-6 will loiter overhead, ready to retaliate against Iranian Silkworm missile sites.

US AWACS radar planes based in Saudi Arabia will be watching carefully as the convoy steams toward Kuwait. All ships in the patrol have electronics that let them receive AWACS data at the same time the AWACS crew does, the Navy says.

Naval experts say the escort operation is likely to take a form largely unchanged since World War II. Two or more warships will sail with each tanker group, passing other Navy vessels loitering on duty at assigned Gulf locations.

Because the escort ships will be a mix of cruisers, frigates, and destroyers, the weaknesses of one type can be compensated for by the strengths of another.

The two Leahy cruisers, for instance, were designed to escort carriers and are best at defending against threats from the air. They have two long-range air search radars, including the SPS 48, which has three-dimensional capability. This means a Leahy ship can determine the altitude of an approaching plane or missile, as well as its distance and bearing.

They have two Phalanx air defense machine guns and can toss up a number of Standard surface-to-air missiles simultaneously, as if each one were a quarterback throwing to many receivers at once.

But the Leahy class was built at a time when the Navy felt missiles were all the weapons a ship needed. They do not have large guns useful against things that float.

``They wouldn't be all that good against a small surface threat like a speedboat,'' a congressional naval expert says.

Thus the Perry-class frigates are a good operational match for the Leahy ships.

The frigates do not have fancy air-defense radar, but they do have a good, modern three-inch gun, a weapon useful against the terrorist speedboat attacks Iran has employed lately.

The Navy's best surface combatants, the new Aegis-class cruisers, might well be able to defend a convoy all by themselves.

They are intended primarily to defend against a massive Soviet attack, but at more than $1 billion apiece, they are not the sort of resource the Pentagon wants to send into the Gulf's constricted waters.

``You put a very valuable ship in there and it's more at risk for an accident like we just had'' with the Stark, Admiral Metcalf said.

Metcalf said Navy ships in the Gulf are capable of handling whatever might come their way. ``You can bet your life we're not going to be putting them out where they can't defend themselves,'' he said.

Under the rules of engagement for the Gulf operation, US ships and planes will be allowed to defend themselves against any target that is displaying hostile intent.

The two Kuwaiti tankers are the first of 11 that will carry American captains and flags and be protected by the Navy in a policy laid down by President Reagan but criticized by congressional opponents who fear it will draw the US into the Gulf war.

Defense Secretary Caspar Weinberger's report to Congress on Gulf arrangements says that ``any aircraft or surface ship that maneuvers into a position where it could fire a missile, drop a bomb, or use gunfire on a ship is demonstrating evidence of hostile intent.''