As of 3 p.m. Saturday, the boat was traveling at seven knots, which is equivalent to roughly eight miles per hour.

The U.S. Coast Guard owns nine of these icebreakers. The Mackinaw is the only icebreaker in the U.S. fleet capable of leaving a wide enough path for large freighters to pass through. The new ...

As ice coverage expands, U.S. Coast Guard officials will assign additional icebreakers as needed. The Mackinaw has a crew of nine officers and 41 enlisted personnel, the Coast Guard said.

The U.S. Coast Guard Cutter Mackinaw is assigned to manage western Lake Superior ... As ice coverage expands, U.S. Coast Guard officials will assign additional icebreakers as needed.