Whatever happened had to happen fast. No mayday or distress signal was given. The crew also gave no indication they were in any trouble other than taking on some water.
She rests in two pieces on the bottom, with a gigantic pile of taconite pellets in between them.
She sank in water that's about as deep as she was long.
rogue wave?
1. The deck hatches over the cargo hold of the ship were not properly secured, or may have been damaged in the storm.
2. As a result, the ship began taking on water almost from the time they left port.
3. The water itself probably wouldn't have caused a catastrophe, but it began to act as a "lubricant" on the taconite pellets in the cargo hold.
4. As the wind got stronger and the waves got bigger, the cargo began to shift in the hold. This was probably what caused the list in the ship when the captain made his last radio transmission.
5. One particularly large wave came upon the ship from the north/northwest (the wind direction), lifting the stern up as it approached from the rear.
6. The combination of the rising stern of the ship and the "lubricated" taconite pellets caused a sudden forward shift in the cargo, instantly pitching the bow down beneath the surface. The weight of the cargo drove the ship straight down to the bottom of the lake like a crashing airplane.
There's some question about whether the ship broke in half from its impact on the floor of the lake, or if the rear half separated in that brief moment after the wave had passed underneath it and the stern was elevated in the air without any support underneath it.