July 23, 2022

Temperature 81 Degrees, Abundant Sunshine and Clear Blue Skies

Coast Guard Cutter Icebreaker Mackinaw Museum Ship

This is the last attraction that we visited while in St. Ignace while we were staying at the Lakeshore RV Park and Campground.

The USCG Cutter Mackinaw is located in Mackinaw City and is easy to find. If you miss the sign there is no way that you are going to miss the huge propeller that was one of three that was once used by the ship.

The USCG Cutter Mackinaw was launched in 1944. It was built to keep the Great Lakes shipping lanes open so that iron ore and copper from the Upper Peninsula of Michigan could be transported to wartime factories in the Lower Great Lakes.

For 62 years the Mackinaw plowed through the Great Lake ice keeping important shipping lanes in the Great Lakes open to commercial traffic.

It was taken out of service in 2006, however, the ship is as ready to be returned to service today expect for one detail. We’ll talk about that a little later.

Come on, let’s take tour of this remarkable ship. There is too much to see and discover in a simple blog so I’ll try and cover at least some of the more interesting things about the ship.

One of the details I was most curious about was, how in the world did the ship actually break a path through the ice? The first thing I learned is that it was designed to break ice that was between 3 and 5 feet thick. This is the norm for ice on the Great Lakes. OK, but that still begs the question How did it actually do it?

What I discovered is that the ship broke through the ice in several ways.

It all begins with its cut back bow which allows it to ride up on the ice and slice down through it.

It also had a bow propeller that was 12 feet in diameter. This propeller would if necessary chew through the ice. Most of the time, however, it was used to hurl the broken pieces of ice back under the hull creating a water wash down the sides of the hull. The water wash lubricated the hull and made it easily slip through the broken ice.

The ship was also designed with no keel to keep the ship steady. Instead, the hull is rounded so that it could be rolled from side to side. To do so there were ballast tanks to port and starboard that could be flooded with about 500 tons of water within 90 seconds. When the tanks on one side were full the process would be reversed automatically sending the water back to the other side effectively rocking the ship from side to side. This rocking from side to side would help with ice breaking. There were also ballast tanks in the bow and stern allowing the boat to be rocked back and forth helping it to climb up on the ice and then slice down through it.

Finally, it always tried to take the path of least resistance. Meaning, it would look for the lightest ice, or ice that is already well broken up and loose, or better still, ice that is formed in patches leaving some open water between them.

I was told that never once in its 62 years of service did it ever become stuck. It was the heavy weight of ice breakers and there is none like it today.

There is more to see and discover so lets keep moving.

Then, the all important area for me

OK. Time to go down a deck to

the engine room. And here is the reason the ship was taken out of service. The ship has a total of six Fairbanks Morse opposed piston engines for which parts are no longer available. Since no parts are available the engines can no longer be serviced. It was for this reason alone that the ship was taken out of service.

I found it very interesting that the diesel engines don’t actually drive the propellers. Rather,

the diesel engines drive generators, which in turn power DC motors which in turn power the propellers. A really neat arrangement, indeed.

And now to finish up our tour we’re going topside.

to the pilot house. This is where most of the navigation and piloting of the ship took place.

The view over the bow from the pilot house. Note, the view of the bow itself is somewhat restricted because of the steel wall around the front of the ship. Because of this,

And finally,

The view out over the stern to Lake Michigan. We’ve now gone from bow to stern, top to bottom in our our tour of the USCG Cutter Mackinaw. I found it to be absolutely fascinating to tour this great ship and to gain an understanding of how it accomplished its mission, of what life on board must have been like, and to see the engines that drove it for some 62 years. I’m definitely glad we took the time just before we left to take the tour.

Thanks again for spending some time with us.  It’s always great to be able to share our story with family and friends. Comments? Feel free to share them with me. And always remember, cherish every moment of every day that God gives you and live those moments to the fullest. 

Our continuing mission remains the same: to explore as many new states as possible, to seek out new acquaintances and make new friends, to boldly go where we have not been before


  1. Bill, this was so interesting! I didn’t know or ever think about an icebreaker ship! This is a tour I would like to take! And I have to say, your pictures are beautiful!! So clear and crisp!! So, if this ship is out of commission, what do they do about the ice now? Another ship? Thanks for your post!


    1. Thank you! I would encourage you to definitely take the tour. They replaced this ship with four new Coast Guard Cutters, each smaller and lighter. I sort of laughed when I read that, it took four to replace the one. And they call that progress!

      Liked by 1 person

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