How did the Fitzgerald sink?

Answer 1

Nobody knows...

There were no survivors and the ships in the area didn't see anything.

The Edmund Fitzgerald disappeared during a severe winter storm with hurricane force wind gusts. A few weeks later, the wreck was found in two pieces on the lake floor.

It was originally assumed that the ship snapped in half while on the lake surface, due to the storm activity. The Coast Guard investigation sited ineffective hatch coverings, which allowed water to flood the cargo hold. An investigation done by the Discovery Channel claimed the ship was sunk by a rogue wave.

The original theory was seeming debunked, because if the Edmund Fitzgerald had broken up on the surface, the two halves would be miles apart (they are yards away from each other). Many people didn't accept the conclusion made by the Coast Guard because they placed the blame on the crew and failed to consider all the evidence. The investigation done by the Discovery Channel found that some of the hatch covers were bowed inward, meaning they were in place and crushed.

So the official cause is faulty hatch coverings.