A bowling ball. Can change some of the script so he catches it before it rolls off the raft but he falls in the water with it. He's too heavy and weak to make it back to the raft so he has to let go and watch it immediately sink or he's taken under too (also a good reference how it's hard to save someone from drowning when you're near drowning yourself). Definitely thought of a dildo first till I saw everyone else put it up though.