The family of an 18-year-old Maryland boater who vanished on the Susquehanna River is refusing to give up hope as a national volunteer rescue organization joins the search.
Mark Everett Coates III, of Havre de Grace, has been missing since Wednesday, Nov. 4, when he was last known to be operating a 10-foot aluminum jon boat near the Hatem Memorial Bridge around 5 p.m., Maryland Natural Resources Police said. His boat was found capsized near Garrett Island the following morning, prompting a search involving multiple agencies…