Hundreds of striking Steelworkers yesterday formed a 13-block picket line outside the Newport News Shipbuilding and Dry Dock Co. in a show of strength, but the company contended that the day's attendance by workers would probably add up to more than 60 percent.

The Steelworkers went on strike last week to protest the company's refusal to recognize the union as bargaining agent for the shipyard's 15,500 production and maintenance workers following a labor election a year ago. The company is seeking to have the election overturned in the 4th Circuit Court of Appeals in Richmond.

The company said that its head count showed that 58 percent of the yard's work force showed up Friday despite the strike, and a spokesman said work on Navy submarines was going well. He said attendance yesterday was even higher than Friday's.

Union spokesman Bill Edwards challenged the company's estimate. "It's obvious they're lying," he said. "It's the oldest trick in the book. Our strike's in good shape."

Meanwhile, police arrested three pickets, bringing the total number of arrests to 24. Two were charged with violating Virginia's right-to-work law by interfering with employes crossing the picket lines, and the third, a union organizer, was charged with disturbing the peace.

The company gave out paychecks yesterday to striking workers for the week before the strike began. Edwards said that thousands of employes showed up at a site outside the shipyard gates to pick up the checks -- a sign, he said, that the strike has widespread support. Police were called briefly to the site after a group of Steelworkers knocked down a gate in the rush to get their checks.