Zack Selby, expecting to gloat over the loss of Nat’s ship, finds himself thoroughly humiliated—especially since Nat brought the
Putnam home through a combination of “book sailing”
and dead reckoning. Through a lifetime of hard work and perseverance, Nat has not only achieved his own success, but he has proven the worth of his system of navigation. As more and more people adopt it, he clearly expects, more lives and shipments will be saved. He’s repaid the debt he owes the men who helped and supported him by working to save and improve the lives of countless others, from the men he taught aboard ship on each of his voyages to the hundreds and thousands of people he’s never met but who have used his book. And as Nat and Polly embrace, Polly’s tears remind readers of the risks that Nat took on this voyage and the courage necessary for him—and her—to face those risks with equanimity.