One way to go about analyzing this powerful short story is by examining its genre of Naturalism and how it goes about conveying Naturalist principles. Literary Naturalism began in the late nineteenth century as a sort of pessimistic offshoot of Realism: in a Naturalist story, characters are impacted by natural forces, and their decisions are determined by those forces. Often, such characters are portrayed as relatively insignificant in the face of a natural world that is indifferent to them. Nature does not adhere to our ideas about justice or fairness, so characters' fates often seem arbitrary or even unfair.
In this story, the insignificance of the characters is signified by the fact that all but one are unnamed. Billie, the oiler, is the most prepared for the kind of labor that being in a lifeboat demands—he is young, fit, and uninjured, and his usual work is likewise difficult—unlike the correspondent (who is not accustomed to hard labor), the captain (who is injured), or the cook (who is out of shape). The story's Naturalism is displayed when Billie is the one man who actually dies in the end. In naming Billie, and only Billie, Crane seems to encourage readers to grow even closer to him, which makes it all the more shocking when he, of all the others, dies.
In addition, the depiction of the sea as an uncaring force, doing what it does, completely oblivious to the men in the boat, further characterizes the story as a Naturalist text.
Many a man ought to have a bath-tub larger than the boat which here rode upon the sea. These waves were most wrongfully and barbarously abrupt and tall, and each froth-top was a problem in small boat navigation.
The waves keep coming and coming, regardless of the men and their feelings or the irony of the fact that they survived their ship sinking and might still die in their "life" boat. There is no fairness, and no God intercedes on the men's behalf; in the end, the story shows that we only have each other to rely on.