Final answer:
The stranger Captain Walton brings aboard his ship seems to be in a vulnerable state, with little explicit information given. Maritime themes are present in the provided excerpts, but they do not directly reveal details about the stranger's identity or backstory in connection with Captain Walton.
Step-by-step explanation:
The information known about the stranger Captain Walton brings aboard his ship is pieced together from various excerpts. In one situation, the captain provides the stranger with whiskey and water to help steady his chills. This indicates the stranger was in a vulnerable state when found.
In another text, it is noted that the captain observed someone on shore through gestures, hinting at the mystery surrounding the character's past. While not explicitly connected to Captain Walton, references to captains and their ships, such as the poem "O Captain! My Captain!" and the captain in another narrative calling out for someone to come to the boat, paint a broader maritime-themed context.
These passages, however, do not directly inform us about Captain Walton's stranger apart from suggesting a maritime connection. Without additional explicit details, it's challenging to construct a more comprehensive understanding of the stranger's identity or story as related to Captain Walton.