The sack cushioned the line and he had found a way of leaning forward against the bow so that he was almost comfortable. The position actually was only somewhat less intolerable; but he thought of it as almost comfortable.
After the sun sets on his first night at sea, Santiago tries to get into a more comfortable position. He had not prepared to spend the night on the skiff and so uses the one option for a cushion, the sack that covered the bait box. He acknowledges his discomfort in the situation but finds the slight adjustment in his position to be a considerable improvement in relation to how he felt before. Santiago’s positive attitude comes into play in forgoing his own personal comfort for as long as necessary in order to catch the marlin.
He settled comfortably against the wood and took his suffering as it came and the fish swam steadily and the boat moved slowly through the dark water.
After Santiago sees the fish jump out of the water on his second day at sea, he sits and tries to relax. The narrator describes him simultaneously as sitting comfortably while resigning himself to suffering. Santiago seems to take for granted that suffering should go hand-in-hand with accomplishment, as if he must make a personal investment in exchange for catching such a large fish.
He did not truly feel good because the pain from the cord across his back had almost passed pain and gone into a dullness that he mistrusted. But I have had worse things than that, he thought.
Santiago privately takes stock of his true condition after he tells the marlin he feels fine and in control. He has gently warned the fish of his strength and challenged the fish to keep pulling the boat, but he has some doubts. Santiago acknowledges he feels pain, but he reassures himself that because he has experienced worse pain before, he can endure. Suffering, like other aspects of his profession, can be skillfully managed.
Now you are getting confused in the head, he thought. You must keep your head clear. Keep your head clear and know how to suffer like a man. Or a fish, he thought.
As Santiago struggles to reel in the marlin, he admires the fish as a worthy adversary, briefly envisioning that the marlin could as easily kill him as he the marlin. He quickly changes his thinking and encourages himself to endure the hardship the contest inflicts. He knows that the marlin, too, must be suffering from this experience, and he resolves to not let himself give in to the suffering before the marlin does.