Final answer:
The author mentions fate in 'The Open Boat' to underline the Naturalistic themes of the indifference of nature, randomness of human predicament, and existential crisis when facing mortality.
Step-by-step explanation:
The repeated mention of fate in Stephen Crane's 'The Open Boat' highlights the Naturalistic themes of the story, emphasizing the indifference of nature to human struggles and the limitations of human understanding and control in the face of vast natural forces. The characters in the story recognize the randomness of their predicament and question the concept of a purposeful destiny that has led them to this point. This preoccupation with fate underlines the existential crisis faced by individuals when confronted with their own mortality and the arbitrary challenges posed by the natural world.