Although the wreck was discovered and surveyed several years ago, the causes of the sinking of the ore carrier Edmund Fitzgerald were not solved until recently. The wreck was extensively investigated by remote cameras in the last year or so by members of the National Transportation Safety Board (yes, they do ship wrecks as well as planes and trains). They solved the mystery of her loss quite easily.
The ship was carrying taconite, a type of small iron ore pellets. These pellets are porous, so a cargo of them will easily absorb water and gain weight at an incredible rate if they are allowed to get wet. The wreck of the ship was found, as expected, with her cargo dumped out. Ore carriers usually capsize when they sink, unless the water is too shallow to allow them to roll over. They flip, dump the heavy cargo, and then roll back upright from the residual buoyancy in the hull. The weight of the cargo made the ship flip over, dumping the taconite out the hatch covers. Once free of the cargo, the ship then at least partially righted herself, struck the bottom bow-first and broke in half. The front half settled upright, the stern is upside down.
The clue that gave away the cause of the sinking was the clamps that hold down the hatch covers. They are universally missing from wrecked ore carriers, as they are ripped off with the hatch covers by the weight of the cargo as the ship flips. In the case of the Edmund Fitzgerald, the clamps were not only still on the ship, but they were in perfect condition, even though the hatch covers were gone. The obvious conclusion from this finding is that the clamps were not securing the hatch covers when the ship sank but were instead left unlocked.
Ore carriers sit very low in the water when filled to capacity and, in a gale, water often washes over the main deck. With the hatch covers not secured (remember, the ship left port in clear weather and the storm blew up rather quickly), the waves breaking over the Edmund Fitzgerald saturated the cargo. As the cargo got heavier and heavier, the ship sank lower and lower. The now dangerously overloaded ship, without a bit of reserve buoyancy, was hit by a large wave (reported by a nearby vessel that was also hit by it), and the vessel was swamped. She sank like a rock. It is hard to accept that the crew did not notice the vessel becoming waterlogged and sinking, but this is a fairly common occurrence in bad weather. Without a steady waterline to go by, no one on board notices the gradual settling of the vessel.
What prompted the reassessment of the sinking is that a few years back the Atlantic Gypsum Conveyor, a conveyer ship full of gypsum, was sailing up the East Coast. A conveyer ship is similar to a tanker, but with onboard conveyer belts below the main deck to self-load dry cargo like chalk, gypsum, talc, etc. A door at the side of the stern allows the ship to offload herself to train cars or hoppers on the dock. The crew of this particular conveyor ship had failed to properly secure this door. In only slightly rough seas, each wave dumped a little more water into the conveyer passage and on into the holds. The gypsum quickly absorbed it, thus becoming very heavy. A Coast Guard plane happened by, and noticed that the ship was very low in the water. It started to video tape the ship, and radioed the crew to offer assistance. The crew responded, basically saying "Help? Why would we need help? Things couldn't be better." The Coast Guard pointed out that the ship was about to sink, which the ship's master did not believe until it was too late. About 10 minutes later the ship dipped her bows into a trough, and never came back up. She rolled over and was on the bottom of the ocean inside of a minute. I don't recall the number of casualties. Had that Coast Guard plane not happened along and alerted the captain and crew, they might have all disappeared without a trace, creating yet another mysterious ship loss.
As a result of this incident, the NTSB decided to re-examine the Edmund Fitzgerald with new video technology which was not available the last time they looked at her wreck. The NTSB also had the Coast Guard revoke the operating certificate of the conveyer ship's sistership until the door was modified to prevent a repeat accident.
The Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin–Madison has background information on the loss of the Edmund Fitzgerald.
Of course, no essay about the Edmund Fitzgerald would be complete without Gordon Lightfoot's song about her.
- 21 October 2001