I don't usually sail over in that area to begin with. We tend to stay away from areas where we know there is a lot of power boat traffic. We tend to go from the Clinton River down to the Lake St Clair Ligh/weather bouy or up in Anchor Bay. I try to avoid going to close to shore anywhere from 9mile up to the Clinton River if possible during the day.
I haven't tried to ever go to Gull Island so I have no idea what depth is like. But I know that over on the eastern side of Anchor Bay it tends to get shallow and especially at night I don't like going places that are questionable, depth wise.