ELBLAG, POLAND -- Edmund Krasowski, an astronomer by training, a subversive by necessity and a lawmaker by the vote of the people of his home district, voyaged in forbidden Soviet waters twice this year to reclaim the seafaring birthright of his constituents.

In a sailing yacht in May and then in a seagoing barge in July, the Polish legislator ventured north. He braved a Soviet submarine net, stared down a Soviet navy patrol boat and ignored two spying Soviet soldiers who were thinly disguised as fishermen.

In so doing, he shattered a Communist-enforced taboo that for 45 years had prevented the people of Elblag from going to the sea in ships.

He also forced into the open a long secret Polish-Soviet treaty that during times of peace guarantees access to the sea for trading ships from Elblag. To prevent Poles from snooping on its huge Baltic naval bases, Moscow had muscled its Communist puppet governments in Warsaw into ignoring the 1945 free-passage treaty.

The unlocking of Elblag is a lesson in how an imaginative local legislator in a suddenly democratic state can bring extraordinary pressure to bear on his own government, as well as on a democratizing Big Brother to the east.

Under the previous Communist-controlled Polish governments, local residents say they were encouraged to forget that Elblag had ever been a gateway to the sea.

"The idea to open -- or rather reopen -- the waterway into the Baltic came to me when I was running for election," explained Krasowski, who won his seat in the Sejm, the lower house of Poland's national legislature, last year in voting that led to the collapse of Communist rule.

"Elblag had great traditions of a seaport connected by regular lines with all major trading centers and ports of the Baltic and North Sea. . . . I decided to try to revive the merchant and sea traditions," Krasowski said.

For the better part of seven centuries, this red-brick city in the fertile flatlands of the Vistula River delta was a thriving and prosperous port. Access to the sea was via the Elblag River, northeast across Vistula Bay and then into the Baltic through a 437-yard-wide outlet called the Pilawa Straits.

The city's major export was wheat from the Polish and Lithuanian hinterlands. Its major import was cloth from England. Its major language was German.

Teutonic knights were invited here in 1237 by a Polish prince who wanted to spread Christianity among pagan Prussians. The German-speaking knights used the city as a base from which they raped and pillaged, terrorized and taxed the people of the Vistula delta, saying they were doing so in the name of the Lord.

Elblag, then called Elbing, evolved into a major port for German burghers of the Prussian Federation, a cluster of trading cities in the eastern Baltic. The federation retained its German culture but allied itself -- for reasons of economic expediency -- with the Polish king.

Throughout most of the Middle Ages, Baltic trade helped ensure that Poland, an East European kingdom that stood shoulder to shoulder with Russia, was firmly anchored in the culture and economy of the West.

Elblag lost its lifeline to the sea during World War II. The Soviet army stormed in from the east and defeated the Nazis, who were using the city's factories to manufacture weapons. In the fighting, Elblag was all but flattened -- more than 60 percent of its buildings were destroyed.

As for the sea outlet, the Soviets seized both sides of the Pilawa Straits. At nearby Baltijsk, the Soviet navy built one of its largest naval bases. Although Moscow had signed a treaty promising free passage, the Soviet government made clear to Warsaw that no Polish vessels were to pass through the straits.

That unwritten rule stood from 1945 until 8 p.m. on May 27, when Krasowski ran the straits in a sailboat.

Krasowski chose to press the issue after having a chat in April in a corridor of the Polish parliament with Foreign Minister Krzysztof Skubiszewski.

The lawmaker from Elblag had earlier asked the foreign minister, in a public question on the floor of parliament, to explain the niceties of the Polish-Soviet sea treaty.

"His answer was very misty. In the corridors he told me, 'This is regulated by a secret treaty. . . . This is a delicate issue.' When I heard this, I decided to set sail," Krasowski said.

The Soviets apparently had heard Krasowski was coming. The steel-mesh submarine net that seals the entrance to Vistula Bay was opened, allowing him to pass into the Baltic.

When Krasowski showed up again on July 31, this time in a sea-going barge loaded with 90 tons of turbine-engine parts from a factory in Elblag, the Soviets again opened the passage.

"I think the Soviets well knew that a deputy of the Polish parliament was aboard the two successful attempts," Krasowski said.

The lawmaker complains, however, that enforcement of the free-passage treaty remains spotty. In August, two yachts attempting to sail into Vistula Bay were prevented from doing so by the Soviets. Regular sea trade has not yet begun between Elblag and the Baltic.

A spokesman for the Polish Foreign Ministry said there is no legal reason for the Soviets to block shipping. The director of sea administration at the Ministry of Transport and Navigation has proposed talks with Moscow over the technicalities of navigating through the heavily guarded straits.

Indeed, diplomatic questions related to the rebirth of the port of Elblag appear more easily solved than logistical ones.

The port has silted up over the past four decades. It would have to be dredged before large, ocean-going vessels could reach the city. Railway bridges, now blocking passage of large ships, would have to be knocked down. New docks are needed.

Feasibility studies have been commissioned to determine if reopening the port would save money for the city's factories. Krasowski, however, says he is thinking about more than economics.

"This port can awaken the conscience and understanding of the people of this region," he said. "People living here were never told."