The yo-yo swings north: exports again surpass imports in the volatile container trades between the U.S. and South America. (Special report: Latin America shipping and ports).

The liner routes between the U.S. and South America are a "yo-yo trade," says Kim Kristensen, director of strategic management for Maersk Sealand in South America, with import and export volumes fluctuating strongly.

These days the yo-yo is headed north.

Imports from the east coast of South America in the first five months of 2002 totaled 164,344 TEUs, outstripping exports to the region, which received 124,644 TEUs from the U.S. That's a big reversal from the prior year, when exports of 167,764 TEUs exceeded imports of 144,545 TEUs.

The continuing strength of the dollar, the meltdown of Argentina's economy and economic problems in Brazil and Venezuela are some of the reasons cited for the big reversal in trade to and from the east coast of South America.

On the west coast of South America, where economies tend to be more stable, imports and exports are both growing, but trade to the U.S. is stronger, fed by strong, regular flows of fruit, forest products and seafood.

Containerized imports from Chile, Ecuador, Colombia and Peru to the U.S. totaled 134,419 TEUs in the first five months of the year, up 12.8 percent over the same period last year. Exports also grew, albeit by a more modest 6.2 percent. Exports to the west coast of South America totaled 79,651 TEUs in the first five months. "Everybody is full northbound," Kristensen said.

Because ships departing ports on the east coast of South America are filled to capacity, some cargo is being "rolled." That means there isn't enough room on the northbound ships and shippers have to wait several days or a week to get their cargoes on the next northbound ship.

"Trade between the east coast of South America and both North America and Europe has been relatively stable over the past six months." said Frank Larkin, senior vice president of Hamburg Sud, the parent company of Columbus Line, Alianca and Crowley American Transport. "But with that stability comes the usual challenges. Ships northbound are running at essentially full capacity when allowances are made for returns of empty equipment. The relative strength of the U.S. dollar against Latin American currencies, including Brazil, makes Southern Hemisphere goods relative bargains, while at the same time dampening the ability of those economies to boost purchases of North American goods."

Bob Gaffney, manager of industry and labor relations for the Port Authority of New York and New Jersey, noted that the economic engine of South America is Brazil. The numbers bear that out: In the first five months of the year, U.S. imports from Brazil jumped nearly 20 percent over 2001 to 121,487 TEUs, according to the Port Import/ Export Reporting Service of the Journal of Commerce. That represents about 75 percent of the containerized imports from the east coast of South America.

"Northbound, cargo volumes include auto parts and assemblies destined not only for the U.S. and …