The 90 foot long ferry Huron became stuck in ice off the harbor at Mackinaw Island, Michigan.  The ferry had departed St. Ignace with 68 passengers on a regular run when it became stuck in a field of brush ice.   The ferry contacted the Coast Guard for help.  They dispatched the cutter Biscayne Bay who freed the ferry and escorted it back to St. Ignace.  Reports state the ferry are not designed to operate in ice and can easily become stuck.  No reports of injuries, damage or pollution being released.