Yesterday marked the 30th anniversary of the sinking of the Edmund Fitzgerald, a 729-ft. freighter that was caught in a catastrophic gale on Lake Superior. The cause of the sinking is still debated, but the official Coast Guard report blamed improperly fastened hatch covers. Others speculate that the Fitzgerald ventured too close to the Caribou Island shoal and scraped the bottom. So why did this mammoth ship take on so much water and dive to the bottom so quickly? We may never know for sure.