West Coast dockworkers and some of the world's largest shipping lines said Monday that they tentatively agreed to a new six-year contract.

If approved, the deal covering more than 26,000 workers would avert a dispute like the one that paralyzed West Coast ports for 10 days in 2002, costing the U.S. economy as much as $15 billion.

The Pacific Maritime Assn. and the International Longshore and Warehouse Union issued a brief joint statement Monday night that paraphrased the words of union President Bob McEllrath and PMA President Jim McKenna, noting that the tentative deal "meets the needs of both workers and the industry. It allows West Coast ports to be competitive and provides the good jobs that workers and communities need."

Details of the agreement weren't disclosed, although both sides said last month that they had crossed a significant hurdle by reaching an agreement on healthcare costs.

They continued to haggle over productivity issues, meeting over the weekend in "marathon negotiations" in San Francisco, the union and employers said.

Neither could afford to rock the boat, labor experts said.

The U.S. economy has been sinking, worsened by the collapse of the housing market and record fuel prices. Import cargo is down at all West Coast ports as a result.

"Any kind of a work stoppage would have reverberated through the U.S. economy, and it would not have accomplished anything for either side," said Harley Shaiken, a UC Berkeley professor who specializes in labor issues. "It's certainly a welcome conclusion, given the overall state of the economy."

It may be several days before terms of the contract agreement are known.

PMA negotiators have to clear the deal with their 71 member companies, which include Maersk Inc. of Copenhagen, Evergreen Marine Corp. of Taiwan and SSA Terminals of Seattle.

For the union, the proposed agreement first goes to the Longshore Caucus -- 100 union officials elected by rank-and-file members. If the Longshore Caucus approves the deal, it then goes to the full union membership for a vote.

There are 15,068 workers registered with the union. The agreement would also cover 11,000 nonunion dockworkers known as casuals.

Union and company negotiators took a different tack from the start in these con- tract talks, beginning their negotiations March 17 even though the old six-year contract wasn't due to expire until July 1.

The talks were disturbed only by relatively mild disputes.

The PMA issued statements complaining of work slowdowns at the two biggest West Coast ports, Los Angeles and Long Beach. The union responded with mild chiding, saying it was better to focus on the talks, not dockworkers' coffee breaks.

Their tone was far removed, however, from the rancor of the last contract negotiation in 2002, which resulted in a 10-day employer lockout at all 29 West Coast ports. That ended only after President Bush invoked the Taft-Hartley Act to reopen the docks.

Both sides had been urged to reach an amicable agreement as quickly as possible by some of the nation's largest retailers, who said that they could ill afford a repeat of the 2002 debacle. That dispute delayed the delivery of holiday shopping season goods for several weeks.

By: Ronald D. White, Los Angeles Times Staff Writer