The rescue missing for a missing teenage Portage boy in the waters of Indiana Dunes National Shoreline has turned into a recovery mission.  The National Park Service, U.S. Coast Guard, Indiana Department of Natural Resources and several local agencies are continuing to search Lake Michigan in the waters of Indiana Dunes National Lake shore off the national park's Portage Lakefront area.  Indiana Conservation officers say the teen, identified as 15-year-old Corey McFry, was swimming with 3 friends in 4 foot waves around 5:30 Sunday afternoon when he either stepped off of the sandbar they were on or was knocked off the bar and went under the water. Two of the friends continued to look for the teen while one friend went in to shore to call 911, authorities say. Lake Michigan in the area of the incident was under a rip current advisory at the time, and no life guards are on duty at the area where the incident occurred.