Our final day on the Lake Superior Diver dawned early. We left Windigo and had a five hour or so ride down the northwestern side of the island to the southern edge where we were scheduled to do two dives on the Chisholm engine.
The Henry Chisholm was a 265 foot wooden freighter built in 1880. In 1898, after surviving a storm, she plowed full steam into the Rock of Ages reef off the southern tip of Isle Royale. She was badly damaged and not salvageable. When the Chisholm sank, the stern section, including the engine, separated from the remainder of the wreck. While most of the Chisholm wreck lies on top of the wreck of the Cumberland, another ship who met the same fate on the same reef, the engine and a portion of the stern lie a little ways away, fairly intact. The engine was a double expansion steam engine capable of producing just over 1700 HP.
Today, the top of the engine is at roughly 120 feet and is approximately 30 feet tall. This was, perhaps, our second favorite dive site, but it really is hard to rank them. The expert craftsmanship in the form of details cast into the engine are still visible. This engine is massive! And deep, not to mention cold. By the end of the second dive on the engine, I was freezing.
After the long descent to the wreck - it took about three minutes just to get there - the first dive started a little rocky. I had slightly over-breathed my regulator and it had started a light free flow. Having that happen at 150 feet it a little unnerving, but is the exact reason we were diving with pony bottles on this trip. Thankfully, slowing my breathing using long, slow exhales, and dialing back the venturi switch, my regulator stopped and we were able to continue on our dive. Unfortunately, this ate up quite a bit of our no-decompression time limits (NDLs) meaning the first dive was on the shorter side.
The second dive went off without a hitch, and after an hour long surface interval. Since Captain Ryan had oxygen hanging for using on our safety stop, we were able to flush out more nitrogen and still have a decently long NDL. Still, at 130 feet, this is only about 13 minutes, give or take a few minutes. This dive we were really able to explore the engine a little more and a little more the stern section that was there. A few feet away from the engine was the propeller, still in excellent, albeit submerged, condition. We were able to see the detail on the engine and see how it was put together and connected to the drive train. Basically, an scuba-diving-engineer's fantasy.
After the dives, it was a two hour boat ride back to Grand Portage. We were sad to see the week come to an end, but so incredibly grateful that we were able to experience it. There are so few people in the world who dive, and even fewer who will brave the icy waters of Lake Superior, we count ourselves among the lucky few who do.
The drive home from Minnesota was long - 16 hours to be exact - and we pulled in to our driveway Saturday evening. While the past two weeks were awesome and relaxing, it was back to reality for us. After all, in two days time, Aaron was set to leave for our next adventure, this time on a different continent.