A U.S. District Court judge has ruled in favor of Bath Iron Works by dismissing a claim filed by the shipyard’s union that was trying to stop arbitration on job classification issues at the yard.

Judge George Singal ruled Friday that a dispute between BIW and its union over plans to change and expand job functions belongs in arbitration and not in the courts. BIW, which is owned by General Dynamics, has argued that the matter properly belongs in arbitration, which started in late May.

“We appreciate the court’s prompt consideration in its handling of the lawsuit. We’re pleased the court agreed the dispute between the company and the union belongs in front of an arbitrator,” said Matt Wickenheiser, a spokesman for BIW.

In January, the company said it wanted more flexibility in assigning work to improve its efficiency in order to compete on what could be $10 billion in new work on Coast Guard cutters. The yard has historically built warships for the Navy.

On April 2, BIW informed the union that it planned to go ahead with its plan to reclassify workers over the union’s opposition and demanded arbitration.

Local S6 of the International Association of Machinist and Aerospace Workers filed its suit April 22 to try to stop the arbitration process. The union’s president, Jay Wadleigh, said at the time that management was inappropriately trying to change the rules while there was an agreed-upon labor contract in place.

“The company filed for an arbitration on this. They are trying to force our hand,” Wadleigh said. “You can’t just – in the middle of it – try to change the rules.”

BIW employs 5,600 people, making it one of the state’s largest employers.