Quote 55
Now they have beaten me, he thought. I am too old to club sharks to death. But I will try it as long as I have the oars and the short club and the tiller. (4.132)
Even when he admits defeat, the old man still continues to try, to struggle.
Quote 56
Now it is over, he thought. They will probably hit me again. But what can a man do against them in the dark without a weapon? (4.161)
The old man recognizes that "it is over" at several different points, yet continues to struggle. This raises the question, when is it actually over?
Quote 57
The wind is our friend, anyway, he thought. Then he added, sometimes. And the great sea with our friends and our enemies. And bed, he thought. Bed is my friend. Just bed, he thought. Bed will be a great thing. It is easy when you are beaten, he thought. I never knew how easy it was. And what beat you, he thought.
"Nothing," he said aloud. "I went out too far." (4.171, 4.172)
The old man seems to say that he was beaten by himself, by his own poor judgment, rather than any other force.