Modern-day pirates with rifles and swift fishing boats continue to rob, rape and murder Vietnamese refugees sailing across the Gulf of Thailand, Prosecution of Pirates in court and programs to increase naval patrols on the gulf appear to have had only minor effect in quelling the attacks.

Recently, a United Nations refugee worker chartered a boat and rescued 36 Vietnamese from Kra Island, lying off Southern Thailand. Since last year pirates have repeatedly deposited refugee victims on the uninhabited island, often returning later to rape and torture them at will.

The lastest rescued group reported pirates had robbed their vessel three separate times during the voyage from Vietnam. On Aug. 12, they were towed to Kra Island, and their boat was stolen. It was not known if women among the group were physically assualted, though one foreigner who works closely with boat people commented, "I'd be surprised if they weren't."

We've had reports of women raped 30 times over the course of three or four days," he said. "We've had cases of women being raped to death."

Since 1975, over 350,000 Vietnamese have completed long and dangerous boat journeys to the shores of adjacent countries. For them, piracy is only one of many harzards to evade.

Though last year Hanoi clamped down on the boat traffic, refugees continue to reach neighboring shores in a steady stream. In June this year, about 10,000 Vietnamese successfully fled their country by sea. In July, the figure was 7,800.

Boat people have not reported cases of mass murder in recent months. Last December, witnesses said 80 people drowned when a boat was deliberately capsized and abandoned by a pirate launch. However, reports of smaller pirate attacks continue unabated.

Diplomatic sources report that of the 71 boats that reached Malaysia in June and July of this year, 21 had been boarded and robbed by armed pirates. Altogether, 13 women were raped and two people killed. Figures for arrivals in Thailand were not available, but sources said they were probably comparable.

One such group of refugees landed in the southern Thai province of Songkhla on June 23, reporting that during nine days at sea their boat was boarded 48 separate times. Small fleets of trawlers, many flying Thai flags and crewed by Thai-speaking men, surrounded the vessel. One by one, they sent armed men aboard.

Three young women, aged 15, 16 and 19, were forcibly taken onto some of the pirate boats and repeatedly raped. One boat of eight pirates that attacked on June 22 fired on the Vietnamese, killing a 2-year-old boy and a 26-year-old man.

Other pirates wanted only to search and rob. The refugees lost gold, foreign currency, watches, clothing and all their navigation equipment.

The fight of Vietnamese refugees has given new life to a centuries-old tradition of piracy and lawlessness in the Gulf of Thailand.

Some pirates are professionals, who even before the advent of the "boat people" preyed on fishing trawlers, hijacking and reselling catchs or capturing and holding for ransom boats and their crews.

But often the men who piliage the Vietnamese boats are "amateurs," ordinary fishermen who happen upon gold and women virtually there for the taking. Rising fuel costs and depletion of fish stocks in the gulf have driven many boat owners toward bankruptcy, making a refugee catch even more attractive.

The past year's recurrent reports of pillage and rape on the high seas have brought Thailand and Malaysia under pressure for action from the U.N. High Commissioner for Refugees and the U.S. government.

Thai officials say they have formed a special committee to deal with piracy.

But with almost 10,000 Thai fishing boats on the seas, long coastline and the pirate practice of attacking in international waters, they stress that their power is limited. "We don't have the strength to be everywhere all of the time," remarked a Foreign Ministry official.

Earlier this year, Washington and the United Nations pooled funds to buy the Royal Thai Navy an unarmed, 38-foot reconnaissance launch to monitor the routes from Vietnam and specifically around Kra Island.

However, after three sorties on the high seas, its cooling system blew out, requiring $10,000 in repairs, diplomatic sources reported. The launch now remains in port, with questions remaining unanswered as to who will pay for the repairs.

Stories like this lead many refugee workers to conclude that the Thai government, while bringing some captured pirates to trial, does not rank piracy as a pressing concern. The navy, it is alleged, has in practical terms done almost nothing to increase patrols of its coastline.

Some diplomats in Bangkok were dismayed to learn recently that a meeting Thailand. Malaysia and Singapore had scheduled to discuss technical aspects of cooperation against piracy had been postponed indefinitely. According to a Foreign Ministry official in Bangkok, the three countries decided such a meeting was "not a necessity" at this time.

For its part, Thailand appears to consider foreign press reports of piracy as an affront to its national dignity. For instance, despite detailed reports from refugees indicating the pirates are almost always Thai, Bangkok officials maintain the attackers' nationality cannot be known.

Moreover, Thai officials often complain the Western world is slow to recognize Thailand's own sufferings. When the pirates' victims were Thai fishermen, no one made a fuss. But when Vietnamese refugees began dying, suddenly there was great international interest.

Some Vietnamese believe the Thai government deliberately lets piracy continue unchecked as a deterrent against the unwanted boat people. Other theories hold the government is wary of a confrontation with the highly organized fishing industry, which can field demonstrators in Bangkok overnight.

There is no direct evidence to support either of these contentions. However, it appears certain that word of the pirates' cruelty and seeming omnipresence has filtered back to Vietnam and changed the minds of at least some potential boat people.

If Thai and Malaysian forces cannot do the job, the U.S. 7th Fleet should be called in, some Western diplomats have suggested. However most refugee officials appear to feel the fleet's presence would offend both Vietnam and the two countries across the gulf.

However, American long-range reconnaissance planes operating out of the Philippines have begun to provide intelligence on pirate attacks.

Prop-driven P-3 Orions make special detours over the gulf and radio word on boat movements' to the U.S. mission in Bangkok. It was an Orion that first spotted the 36 Vietnamese who were rescued from Kra Island this weekend.

Some refugee workers pin their hopes on the dissuasive effect of bringing pirates to trial in Thai and Malaysian courts. U.N. officials question victims for registration numbers of attacking vessels, descriptions of individual pirates and other evidence admissible in court.