PORTLAND, Maine — Hundreds of employees at one of the U.S. Navy’s biggest shipbuilding contractors voted Saturday to approve a contract deal with Bath Iron Works, ending a weeklong strike. Members of the Bath Marine Draftsmen’s Association ratified a new four-year collective bargaining agreement that goes into effect immediately, the shipyard said. That followed an hourslong union meeting at a high school. “We look forward to working together once again to deliver the Navy’s ships on time to