By JOHN RICE
  Associated Press

  HAVANA - As the tugboat El Jaguar towed the squat, green barge Helen III into Havana harbor on Friday, the U.S. flag waved in greeting from the fort at the bay's entrance for the first time in 42 years.

  The 323-foot-long barge -- resembling a floating, tarp-wrapped warehouse -- was the first U.S.-flagged commercial vessel to enter the harbor since the United States broke relations with Cuba in 1961. Raising a country's flag over the Moro castle at the harbor entrance is the traditional greeting for foreign vessels.

  ''When I saw the Cuban flag pass, I felt like it was the first day of class, I was so nervous in my stomach,'' said Charles Turner Fabian II, vice president for operations of Maybank Shipping of Charleston, S.C., onboard the Helen III.

  The United States ended relations with Cuba and imposed an embargo on shipping to Cuba in 1961 as Fidel Castro's government turned steadily toward socialism. One memory of those decades of hostility was the name of the dock complex where the ship docked: Haiphong, in honor of a North Vietnamese harbor bombed by the United States during the Vietnam War.

  Since the collapse of the Soviet block in 1991, however, Cuba has eagerly sought trade with the capitalist world while trying to maintain a communist system.

  Numerous ships have carried U.S. goods to Cuba since December 2001, when the U.S. government permitted cash-paid shipments of food and some other goods.

  Seventy-one percent of those were U.S.-owned, said Pedro Alvarez, leader of the Cuban government import company Alimport, which has signed contracts for about $480 million since the rules were eased.

  But the Helen III was the first to carry cargo under a U.S. flag and with a U.S. crew. It was also the first vessel from Mobile, Ala., to carry cargo under the recent rules.

  Fabian said the barge carried 1,614 metric tons of newsprint and about six tons of timber.

  As tugboats maneuvered the barge to the docks, Fabian stepped aside to make a phone call to check the company bank account. ''By law, the money has to be in our bank account before we can unload,'' Fabian said, referring to the U.S. regulations that set conditions on trade with Cuba.

  Fabian said the shipment, worth about $1.5 million, was part of a contract to ship a total of 10,000 tons, with another 5,000-ton deal in the works.