IIRC, the radar operator at Whitefish Bay said the Edmund Fitz’s blip looked normal on one sweep, and on the next sweep ten seconds later it was gone.
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.
I worked on ore boats on the lakes for about five years.
And yes the Lakers are called ore boats not ships.
The Fitz’s was fully loaded with iron ore pellets. It is very possible she sank in just a few seconds. There certainly was no time to launch the lifeboats or life rafts. The ore boats do not have water tight compartments to speak of.