USCGC Mackinaw (WLBB-30) is a vessel built as a heavy icebreaker for operations on the North American Great Lakes for the United States Coast Guard. IMO number: 9271054. She should not be confused with a namesake ship, the USCGC Mackinaw (WAGB-83), IMO number: IMO 6119534, which was decommissioned on June 10, 2006. The Mackinaw can be seen and toured at Grand Haven's Coast Guard Festival every summer. The ship was also featured on the television series Modern Marvels.