DesertFox is right about this. All the boaters I've ever known either took their trash ashore or made sure that what went over the side sank stright to the bottom. I've seen plenty of boaters toss beercans over, but not a one that was not ripped open like an empty banana peel. I'd note that almost all of those who I saw do this did so because the local authorities did not apporve of them drinking at all, in part because they were under 21. Boaters take floating trash back ashore with them.