There are other theories as well, although your is slightly more likely than the other two. Over the years I have chatted with Coast Guard officers who are knowledgeable about the sinking.
1. The ship caught a wave on the bow and a wave on the stern
and the bottom fell out.
2. The Coast Guard resounded the depths of water near the sinking. There is the possibility that the Fitz’s bottom actually scraped lake bottom.
3. My own personal belief is no matter what theory is correct, the Fitz was cut in half and lengthened; her hull
was not as strong after that.
Good post. The possibilities are intriguing.