St Clair River, those big ships fly down that river, seen em boot down that river many times. If you are underwater for like 10 minutes or longer you could easily not see that boat when you were on the surface before you dove down.
I think it's a cool underwater shot. Not seeing anything freak-out worthy though. If you are diving (as opposed to snorkeling), you are presumably going down farther than a boat hull/motor can reach you. And when you're ready to surface you should, you know, look up right?