TEQUESTA, Fla. — Families hoped for a miracle even as science nagged that one was improbable and rescue crews went into a seventh day of searches Thursday for two teens missing at sea.

Though it seemed unlikely a medley of agencies would continue their hunts much longer, the Coast Guard, which is leading the effort, insisted it remained an “active and open” case now focused off the Georgia and South Carolina coastline.

Chief Petty Officer Ryan Doss said crews would continue surveying waters from Florida up through South Carolina throughout the day Thursday and overnight into Friday. A determination on plans for beyond that had not been made, but Doss said there were no immediate plans to call the search off since it was believed there was a chance the 14-year-olds, Perry Cohen and Austin Stephanos, were still alive.