Blocked lock takes its toll on St. Lawrence Seaway. Shippers may lose patience, with 54-year-old system

Canadian farmers, US businessmen, and economic planners in Moscow are among many people paying close attention to 125 feet of concrete. The concrete, a collapsed segment of a lock along the St. Lawrence Seaway, has halted waterborne shipments into and out of much of the Great Lakes. Unless repairs are swift, the damage, which occurred Oct. 14, is likely to undermine confidence in a system designed to give the United States and Canadian interiors a cheaper, more direct link to oceangoing commerce.

Over the short run, a temporary shutdown of the Seaway, which links the Great Lakes to the Atlantic Ocean, is far tougher on Canada than the United States. Canadian companies account for the majority of seaway traffic.

By the weekend some Canadian shipowners were speculating that the shutdown might last as long as six weeks. And a few officials of companies with ships on either side of Welland Canal, where the damaged lock is located, started laying off crew members and making alternate plans to transport cargo.

Canadian authorities responsible for operating the Welland Canal's locks said it might be a week before they know how long repairs will take. Steel beams were stretched Saturday across the lock to brace it during repairs.

Ships awaiting passage though the canal, which links Lakes Erie and Ontario, are carrying everything from westbound factory equipment and imported steel to eastbound grain, the first shipments in a $1 billion grain contract between Canada and the Soviet Union.

Canadian grain generally travels by rail from western Canada to Thunder Bay on Lake Superior, where it is loaded on ships. Though the grain could be sent to the East Coast by truck or rail, there were some early reports that Canada's rail capacity was too limited.

That prompted an offer from across the border. Association of American Railroads spokesman Frank Wilner says the US has 16,000 surplus grain cars readily available for rent. ``We have tremendous excess capacity.''

But Angus Laidlaw of the Dominion Marine Association, a trade association representing Canadian ships, says: ``We're not short of rail cars for transporting grains -- what happens is they're sometimes in the wrong place at the wrong time.''

As a result, says Joseph Hartley, a professor of business administration at Indiana University, prices for Canadian grain -- the prime product moved through the seaway at this time of year -- can be expected to rise. Amid speculation that the US might now somehow fill some of the Soviet contract, grain prices in this country rose on the futures markets immediately after the Welland Canal closed.

The US traditionally uses the seaway for less than 15 percent of its grain shipments. The balance goes either by rail to East Coast ports or by barge down the Mississippi River to the Gulf Coast. Barge traffic to Gulf ports is expected to increase if the seaway crisis persists.

Howard VanderMeer, president of the Rail to Water Transfer Corporation, a Chicago dock company that transfers bulk commodities from trucks and rail cars to ships and barges, says some of his customers are already diverting their cargo to these alternate routes.

For example, shipments of clay bound for Europe are now headed down the Mississippi rather than out the seaway. ``People will ultimately have to look at alternative modes of transport,'' he says.

Although the lock wall collapsed just two months before the seaway usually closes down for the three worst winter months, fall is an important season for shippers. In December, the seaway closes for three months because it ices up in the winter. As a result, fall represents the last chance to ship the harvests out and stock up on the raw materials that represent the bulk of the cargo moving through the seaway. Ship owners and port officials are expected to press for at least a one-month extension of the

navigation season.

``If the weather enables us to extend it, I'm sure we will,'' says John Adams, a deputy chief engineer with the St. Lawrence Seaway Development Corporation, which operates the US portion of the Seaway. Though the Seaway itself is less than half the age of the 54-year-old Welland Canal, the latest incident has sparked calls to check the whole system.

``If any one of these locks shows a failure like that, you can suspect that others might be ready to go, too,'' notes Harry Benford, a professor of naval architecture at the University of Michigan.

By most assessments the wall collapse is so far only a modest setback. But those concerned about the seaway's future, where traffic has been declining since 1979, say they hope the incident won't further erode confidence in the system.