I have never been able to make it in 13 to 14 hours. I usually spend a few hours anchored in a small cove off Wyandotte near a small island I don't have the name of at the moment. Not the most comfortable place, but out of everyone elses way. I got there around 11:30 PM after leaving at 11 in the morning. You may make better time as I am not so much into speed when I sail. I also solo most of the time and prefer not to sail when I am tired, prefering instead to stop and head back out after resting.
The shoaling near the Detroit light appears to me to be 2 or 3 shallow spots south and west of the light. There seems to always be a lot of vegetation growing in the area. Also my charts are kind of old, and the shoaling my be nonexistant today. As I said I have not had a problem there, only a minor concern.
Again I have never made the run from Wyandotte to the St Clair river without getting later into the day. You may have better luck as stated earlier, it doesn't take a great deal of speed to do a horizon job on me generally. Good Luck and have a good safe trip Wes Carroll