Writer, diver, and Northerner Jason Heaton took our new Preservation Vest along for a field test on a recent trip to dive the icy depths of Lake Michigan. Read his firsthand account:

The bottom of Lake Michigan is no place for the living. Both my dwindling air supply and the scene of destruction in front of me were reminders of this fact. With one final survey of the wrecked ship, I aimed for the sun above, ascending hand over hand up the mooring line. The sunken railroad car ferry, SS Milwaukee, had laid on the 120-foot muddy lake bed, for close to a century. The ship sank in a gale in November of 1929, taking all hands and a heavy load of railroad cars with her. The chaotic jumble—a shipwreck on top of a train wreck—is  grim evidence of the power of the Great Lakes. It’s also a privilege to witness once in a while, when the lake allows it. I’d be back, but not today.

Only half an hour earlier, I had been on the rear deck of a small boat bobbing on the light chop, zipping shut my drysuit, pulling on my fins, and wiping my dive mask. Dives in the Great Lakes are short. The water is cold, very cold—my dive computer would read 41 degrees Fahrenheit at the lake bed. The depths of most of the wrecks found there mean limited bottom times. Diving in any of the lakes requires specialized skills and equipment and some measure of cold tolerance. But it is worth it. The cold, fresh water preserves the steel and wood of shipwrecks so that many of them look much as they did on the day they went down. And there are a lot of shipwrecks in the Great Lakes—over 10,000 by some estimates. The short frequency waves and fickle weather have brought many vessels, big and small, to their untimely ends. Most have been cargo freighters that plied the lakes from Duluth to Detroit, but others were international ships from Europe that came to the lakes through the St. Lawrence Seaway and the Soo Locks.

While the shipwrecks often seem suspended in time, one thing has changed over their histories. Invasive mussels—quagga and zebra—were introduced to the lakes in the ballast tanks of oceangoing vessels and have since coated almost every shipwreck in four of the five Great Lakes. Only Superior remains mussel-free, and despite various theories—depth, cold, lack of extensive agricultural runoff—no one knows exactly why. Regardless, the largest freshwater lake in the world is the last bastion of pristine shipwrecks in the United States.

I have dived all over the world, from the Caribbean to the Indian Ocean, but the Great Lakes remain my favorite place. Part of it is the sheer number of shipwrecks to explore, part of it the challenge of it, but also the sense of adventure. I can load up my truck with tanks, dive gear, and warm clothes, and set off for some corner of Huron, Michigan or Superior to dive a wreck only a few people have seen. It feels like a proper expedition. Every time I go, I am reminded of how special this region is and how precious these truly great lakes are. There is something about being in the cold depths that makes the sun seem that much warmer. And life just a little bit richer.