Machinists at Bath Iron Works would get signing bonuses, raises and pension gains under a tentative four-year contract, the union said Friday.

The International Association of Machinists and Aerospace Workers, which represents about 3,200 mechanics, fitters, welders, painters and electricians, will vote on the tentative deal Sunday at the Augusta Civic Center.

Pending ratification of the contract, each union member would get a $3,000 signing bonus, said John Carr, a union spokesman. Raises, which take effect during the second year of the contract, would be in the range of 2.25 percent to 2.75 percent a year, he said.

Meanwhile, the union “held the line on health care costs and maintains the levels below the national norms,” Carr said. There would be no change to current health care coverage, and there would be no deductibles or co-pays until 2014, he said.

BIW also increased the amount it contributes to the union employees’ pension plan, Carr said.

The company, a unit of General Dynamics Corp., declined to comment. BIW employs 5,400 workers.

The tentative agreement was reached at midnight Wednesday. The Local S6 negotiating committee is unanimously endorsing the company’s offer to the membership.

If the contract proposal is rejected by union members, a strike authorization vote will be held. A strike could begin at 12:01 a.m. Monday if the proposal fails, Carr said. BIW has not had a strike since a 55-day walkout in 2000.

The company, one of Maine’s largest employers, depends on Navy defense contracts. The Navy is expected to decide later this year on contracts for nine destroyers. BIW is competing against Huntington Ingalls Industries for the DDG-51 destroyers the Navy will buy through fiscal 2017.

Staff Writer Jessica Hall can be contacted at 791-6316 or at:

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