For all the accolades that have been thrown at “CODA” this awards season, writer-director Sian Heder and her cast give full credit to the pre-shoot preparations — including two weeks spent on fishing boats in Gloucester, Massachusetts, learning the ropes with grizzled fishermen. “We literally went to sea together before we started filming,” Heder said during TheWrap’s Awards Screening Series panel on Thursday, where she was joined by by SAG Award-winning cast Emilia Jones, Marlee Matlin, Troy Kotsur and Daniel Durant.