Final answer:
The narrator of 'The Open Boat' sees the sea as hostile, as evident in descriptions of relentless waves that threaten to swamp the boat, likening the situation to navigating threats, and portraying the sea's indifference to their struggle.
Step-by-step explanation:
The parts of the excerpt from Stephen Crane's "The Open Boat" that describe the sea as a hostile entity include descriptions of the sea's relentless waves and their effect on the small dinghy. Phrases like "nervously anxious to do something effective in the way of swamping boats" and "each froth-top was a problem in small boat navigation" contribute to the depiction of the sea's hostility. Moreover, the analogy of the waves being "like rocks" and the sea's indifference toward the men's plight add to the interpretation of the sea as menacing and relentless.