SS Glenlyon Wreck

SS Glenlyon is a 328-foot steel freighter wreck scattered over a reef off Menagerie Island. It's an offshore Lake Superior dive, not a shore stop; the NPS depth range runs from about 15 to 60-plus feet. Keep it on your list if you're already equipped for remote, cold-water wreck diving. Every diver must register a dive permit at Rock Harbor, Windigo, or Houghton before going out, then return it after the trip.

Surface water rarely tops 55°F; below 50 feet it can be 34–37°F. NPS says a full wetsuit is necessary and recommends a drysuit. There are no air or gas fills on Isle Royale, and emergency care isn't close by. The wreck broke apart and is spread across the reef, with exposed machinery among the remaining pieces. For an underwater photo, include the exposed gear and engine assembly in one wide frame; it gives a better sense of the wreck than a tight detail. Federal law protects the site and its artifacts, so leave anything you find where it is.

Built in 1893 as William H. Gratwick, the ship became Minnekahta in 1911 and Glenlyon in 1918. On November 1, 1924, she was seeking shelter in Siskiwit Bay when a severe gale drove her onto a submerged reef off Menagerie Island. The crew survived, but the ship broke apart over the following winter.