Can a manatee die as a result of being struck by the propeller of a boat?

There are as many chances of a manatee killing a human being than there is for you to die of a car accident 1 day, 4 hours, 10 minutes, and 45.67 seconds after winning five million dollars in a lottery (I made that up myself). That's because, except for teeth, they don't have any way to kill you, or even defend itself from you.