Old captain symbol
The old captain symbolizes the supernatural, superstitious aspect. Mr. Barns insists that the reason the ship is not moving and it got struck by the disease is because of the late captain, or rather his spirit. At some point, even the narrator feels himself baffled and going insane which leads him to consider this possibility.
Motif of travel
The motif of travel is there alongside the search of self-discovery. To find himself, the narrator had to set out on this long unpredictable journey because the comfort of his life leads him to thoughts of nothingness and emptiness of life.
Ship as allegory of life
A ship is often portrayed as an allegory of life, and this case is no different. Life is a journey: it is unpredictable and dependent on the human interaction just like life on a ship is dependent on human cooperation which is crucial in dangerous situations. The ship's crew is working together and helping the captain despite their exhaustion, because that is the only way to get out of a crisis.
