I think buoys used to have bells attached to them, or maybe still do. If the man is trying to reach a buoy and subsequently dies (drowning from exhaustion before reaching, likely), he was already in the water and was hoping to reach it in order to survive (surviving is a good thing).
So, was the man trying to reach a buoy that had a bell, in order to hold onto it for dear life?
When you said no to boats, do you mean no to all kinds of boats, rafts, and the like?