ast month, Le Thi Anh Phuong and 40 other Vietnamese set off from Rach Gia on the southwestern coast of Vietnam in a small wooden boat.

As they approached Thailand, they were attacked four times by pirates. Each time they were robbed, and each time the other vessel rammed their frail craft. Then on Nov. 30, with their boat foundering in heavy seas, a Thai fishing boat came to the rescue. The fishermen gave the Vietnamese food and water and began towing their boat. When it sank anyway, the fishermen took the refugees aboard their own vessel.

However, the fishermen were fearful of violating strict Thai immigration laws that impose harsh penalties on Thais who take Vietnamese refugees to shore or harbor them on Thai soil. So the fishermen built rafts for the Vietnamese and put them to sea about half a mile off the Thai fishing port of Songkhla.

Of the 41 boat people, 28 never made it to shore in the rough waters. Le Thi Anh Phuong, a 23-year-old student, was the only woman among the 13 survivors who reached Thailand.

In a way, this story reported by refugee officials is typical. Of the 21 Vietnamese refugee boats that made it to Thailand in November, 17 were attacked by pirates. The average number of attacks was 3.5 per boat.

This is consistent with U.N. statistics lately, which show that 80 to 90 percent of the refugee boats reaching Thailand have been attacked by pirates, many of them several times.

However, the more unusual account of the circumstances in which 28 persons drowned underscores a source of mounting U.N. concern about Thailand's policies toward refugees.

Some refugee officials say that tough Thai measures are responsible for the deaths of some refugees who might otherwise be saved. Moreover, the officials worry that the Thai policies, designed to deter Vietnamese boat people from coming here in the first place, are indirectly encouraging more frequent and more brutal attacks by Thai pirates.

In fact, according to U.N. officials, November has been the worst month on record for pirate attacks on Vietnamese boat people.

Usually, the number of confirmed Vietnamese refugee deaths directly attributable to pirate attacks averages one for every 100 boat people who arrive in Thailand safely, according to U.N. officials. But last month the rate was more than one for every 10. According to the officials, at least 101 persons were confirmed killed and an additional 43 were missing and presumed dead. About 950 Vietnamese arrived safely.

In one of the more brutal incidents reported last month, pirates robbed a boatload of 19 Vietnamese, sank the boat and threw all 12 men overboard to drown, according to refugee officials. The pirates abducted four women and three children, including a three-month-old baby, and repeatedly raped the women over a 10-day period before throwing all into the sea.

Two of the women were picked up by a fishing boat after clinging to plastic jugs for three days and nights, but were thrown overboard again the next day because the fishermen feared complications. Another fishing boat then picked them up, and they eventually managed to swim to shore.

"It seems that lately the attacks have become more vicious," one refugee official said. He said the rates of murder, abduction and rape were up.

One possible explanation, the official said, was the termination of a Thai antipiracy program at the end of September. The $2 million program, funded by the United States, ended when it ran out of money after six months and the Thai government rejected a U.S. offer of an additional $600,000 as too little to keep it going.

Now, however, the Thai government is considering a proposal by the office of the U.N. High Commissioner for Refugees to raise $3.6 million for a one-year antipiracy program. Although the Thais originally requested $34 million, U.N. officials said they expected a positive response to the proposal shortly.

Another explanation for the increasingly brutal incidents of piracy is that, despite Thailand's expressed concern about the problem, pirates find some sanction in the government's hardened attitude against boat people.

"One hopes it is not a percolating effect of the tougher government policy," a refugee official said. "But I think it would be better if the government promoted rescues." He noted that an increase in murders by pirates coincided with the harsher policy, under which Thailand said Vietnamese boat people arriving after Aug. 15 would no longer be eligible for resettlement in third countries but would be placed in austere camps.

Another aspect of the policy is that anyone caught bringing "illegal immigrants" to Thai territory faces criminal charges providing for stiff fines and jail sentences. According to Prasong Soonsiri, head of Thailand's National Security Council, harboring such a person in one's home is punishable by 10 years imprisonment.

Under the law, fishing boat captains have been arrested for helping Vietnamese refugees.

U.N. officials argue, however, that the Thai government and fishermen have an obligation to try to rescue Vietnamese boat people in distress under provisions of the international Convention on the High Seas, of which Thailand is a signatory.

"Here we have 28 people dead because Thai courts have seen fit to punish people for acting in accordance with international law," a refugee official said, referring to the incident reported this month.

Prasong said he was not aware of the high seas convention provisions, but that Thailand "can't help" such incidents as the recent drownings "because we have to respect our own laws."

Despite the way pirates may interpret their government's attitude toward Vietnamese boat people, Western diplomats say there is no evidence that the Thai government actively encourages them or regards them as a useful deterrent to refugees. In fact, Thai authorities have dealt firmly with pirates when they are caught.

In one recent case, a sailor in the Thai Navy was sentenced to 25 years in prison for raping a Vietnamese woman. So far this year, about two dozen other Thais have been charged with various offenses related to piracy.

However, some of the worst offenders are believed to go free. They are the ones who kill all the refugees and sink their boats, leaving no witnesses and no evidence.

According to the refugee officials, some of the pirates are Vietnamese or Malaysians, but most are Thais. Often, they are fishermen who attack refugee boats as a sideline.

Although only a small fraction of Thai fishing vessels are involved in piracy, the boats range widely, and some apparently go out of their way to find Vietnamese refugees.

While piracy has long been common in Southeast Asian waters, refugee officials say, the combination of thousands of usually defenseless boat people, long-standing enmity between Thais and Vietnamese and hard times for the fishing industry in the overworked gulf have seriously aggravated an age-old problem.

Despite the frequency and brutality of the pirate incidents, Western diplomats believe they have not significantly deterred Vietnamese from fleeing their homeland. Rather, the attacks have caused some boat people to change course in an effort to avoid Thailand.