BATH, Maine — Two weeks after the largest union at Bath Iron Works sued the shipyard alleging it violated its contract with workers by seeking to modify job descriptions outside a formal contract negotiation, the company Tuesday asked a federal judge to dismiss the suit and allow arbitration scheduled for the end of May to resolve the dispute.

The International Association of Machinists Union Local S6 filed suit April 22 in U.S. District Court, asking a federal judge to rule on its objection to the company’s plan to implement what Jay Wadleigh, president of Local S6, said were “more than 100 changes and additions to people’s jobs and tasks.”

BIW claims the changes would make the yard more efficient, affordable and competitive for Navy contracts, as well as a new line of Coast Guard cutters. But union leadership says the proposed job changes will have the opposite effect and that a similar job reclassification led to chaos before the “cross training” was eliminated in a 2001 memorandum of understand.

The union also contests the company’s broader effort to change job descriptions and tasks falls outside that agreement and instead should be the subject of negotiations leading into the 2016 contract.

The motion to dismiss, filed by BIW attorneys Peter J. DeTroy III of Portland and Daniel P. Bordoni and Thomas E. Reinert Jr., both of Washington, D.C., calls the disagreement “a routine contractual dispute,” arguing, “Local S6 nonetheless asks this court to interpret the meaning, scope and purpose of the 2001 [memorandum of understanding] and to rule that employee job function changes proposed by BIW are not covered by the 2001 MOU. In essence, the union’s action for declaratory judgment before this court seeks both to evade the union’s obligation to resolve this contractual dispute in arbitration — which is already scheduled for May 29, 2015 — and to obtain a favorable court ruling on the merits of an issue of contract interpretation.”

A hearing before the American Arbitration Association is scheduled for May 29 in Bath.

“We think these issues we’re raising, these proposals, should be absolutely and fully discussed in the appropriate venue,” shipyard spokesman Matt Wickenheiser said. “If it’s not at a table across from each other, then with a third-party arbitrator.”

But Wadleigh said that under the collective bargaining agreement, the company can only call for accelerated arbitration like this after the union has filed a grievance about the action, but the union has filed no such grievance.

“The company hasn’t implemented [the proposed changes], and until they implement them, we won’t grieve it,” Wadleigh said. “They want to have the benefit of getting a decision without actually risking anything. They’re trying to apply the memorandum of understanding out of context.”

Tensions between management and the union markedly have increased in recent months, and Wadleigh said in March the conflict was the worst since a strike 15 years ago.

In 2000, Local S6 workers went out on strike for 55 days, fighting to eliminate the cross-training policy then proposed.

On March 24 of this year, nearly 1,000 members of Local S6, which represents about 3,000 shipyard workers, marched the length of the shipyard to protest changes now proposed by the company, including a return to the policy of cross-training.

Another rally along Washington Street outside the shipyard is scheduled for 11:35 a.m. Thursday, May 21.

In a newsletter published Friday, union leaders wrote that before the 2001 memorandum of understanding, “cross-training was outright abused” by the company.

The newsletter states that at a recent meeting, company management indicated “the company’s intent was not to abuse these new ‘rights’ that they have self-proclaimed; it was simply to reduce handoffs and prevent needless stand-around time so mechanics could finish their jobs. … [But] the company routinely violates the contract now and grievances are being filed on a weekly basis. How can anyone with even a little common sense believe that this is how the ‘proposed changes’ would work out?”

Wickenheiser declined to comment on the union newsletter.

In other news, the union said it has filed for accelerated arbitration regarding a decision by the company to outsource powder-coated electrical boxes and filed a grievance on subcontracting dressers.

In November, the company announced it would subcontract 11 items currently produced by members of Local S6. The union opposed that decision. In February, the company said it would not subcontract two of the items, according to the union.

In April, with no agreement on the other items, BIW filed for accelerated arbitration, asking to have all nine items heard together. The union opposed combining the items. Attorneys from both sides were expected to meet with the assigned arbitrator by phone Friday to determine how the arbitration would proceed.