Local S6 union members vote this weekend to decide whether to accept the contract proposed by the shipyard, as well as whether to strike for the first time in 20 years.

With the help of the BIW-built machines, Guilford-based Puritan Medical Group will double its monthly swab production from 20 million to 40 million.

BIW’s final three-year contract offer includes an annual 3% pay increase, maintains current premiums on benefits including 401(k) and life insurance but would increase health plan co-pays. A union committee has rejected the proposal, putting negotiations in flux.

Workers held a demonstration Wednesday morning to show solidarity as union officials negotiate for higher wages, among other demands.

While a strike hasn’t been declared yet, the union plans to hold a rally outside the union hall on Washington Street in Bath on Wednesday at 6 a.m.

“If BIW doesn’t cease its union-busting tactics and come back to the table with a suitable offer, our membership will likely have no other option but to strike,” Chris Weirs, president of Local S6, BIW’s largest union, wrote Monday. “The last thing we want is a strike, but we are prepared to do so if needed.”