Please explain the following quote, "But I must get him close, close, close," he thought. "I mustn't try for the head. I must get the heart. Be...

Santiago has been battling this marlin in the heat of the day for a while now. He is tired and beginning to get weak from the fight. He needs to harpoon the fish and get it off his line, but a head shot would not guarantee death and he cannot risk not killing it. If he only injures it, he would then have lost his harpoon and still be battling the marlin. He knows if...

Santiago has been battling this marlin in the heat of the day for a while now. He is tired and beginning to get weak from the fight. He needs to harpoon the fish and get it off his line, but a head shot would not guarantee death and he cannot risk not killing it. If he only injures it, he would then have lost his harpoon and still be battling the marlin. He knows if he is going to kill it, he needs a sure shot, and that is a shot to the heart.

By saying, "Be calm and strong old man," he is essentially talking himself up...giving himself confidence to make the shot. He can "only see in flashes now" and his hand are "all mushy" because he is so tired and weak. He is trying to gather himself so that he can do what needs to be done, otherwise this battle has been for nothing.