I don't have a lot of experience on the Great Lakes, but I do remember with fondness a project that involved diving on shipwrecks within Isle Royale National Park.

The standard, typical shipwreck tale started with, "trying to make one more voyage before the onset of winter and freeze up, the SS XYZ set out", encountering a storm that overwhelmed the vessel. Don't try and beat Mother Nature. This probably isn't as much an issue now, with more accurate weather forecasts.

If you are going out on the water, especially in kayaks and small craft, you must be prepared to be in the water. This means appropriate clothing, which on the Great Lakes should be some sort of a dry suit most of the time. Your survival gear must be prepped to withstand immersion. You may be in the water or some time before reaching shore.

These in general are the precautions I have taken when kayaking around the Channel Islands, where the water is rather cool (45-55F) most of the time.
Geezer in Chief