Read the passage. A 40-ton creature was coming right at my boat, spinning round and round. We could hear his fins slapping the water with each revolution. The brute exhaled and salty water sprayed us before he dove again. The sight of his tail revolving around, barely missing the boat, sent shivers down my spine. When he came to the surface again, we could have counted the barnacles on his enormous head. What did the writer hear slapping the water?
the boat
the anchor
the barnacles
the fins