Crane's "Open Boat" has defied categorization. For instance, some critics feel it is a Naturalistic story in the point of view that an unsympathetic nature allows the men to be at the whim of the sea; others perceive it as an Existentialist narrative as the correspondent realizes the absurdity of the human condition; finally, some critics, such as James Nagel, who is in Stephen Crane and Literary Impressionism, contends that Crane's fiction mimicked the concepts of the Impressionist painters.
By emphasizing the flawed perspective of individuals, Crane did not simply attempt to reconstruct 'reality,' but rather showed that reality cannot be reduced to a single viewpoint.
Just as the Impressionists broke the painted object into its pieces as reflected in the light of "plein air" [the outdoors], so does Crane have the various characters in his short story view their fates as they interpret what happens with the natural forces.
Perhaps, then, you may wish to take this perspective of Impressionism and explain how the different characters have "flawed perspectives." If you choose to do so, research the ideas of Impressionists and the essay by Nagel.
Or, you can take the Existential approach, which is different from the norm, as well. Either of these approaches will make your analysis/interpretation of the story more intriguing. Good luck.