There is also patriotic symbolism here through the use of the words “pennants” (from the line “steamers’ pennants of smoke”) and flag (from “Flaunting from many a spar the flag that I love”). Although there are sailors on the ship and the ships create smoke on the way to war or wherever, each ship carries the national symbolism of its country, America (which Whitman is absolutely proud of).

dilates: to become wide : swell

jibs: the small triangular headsail on a sloop

freighted: to load with goods for transportation

flag: a usually rectangular piece of fabric of distinctive design that is used as a symbol (as of a nation), as a signaling device, or as a decoration

***all definitions from merriam-webster.com***

“resumed upon myself” (line 1)–the narrator turns here to personal reminiscence.

“scenes ephemeral” (line 3)–see Specimen Days, 1876 onward. Remembrance of extensive time spent in nature in New Jersey.

(line 4)–see Specimen Days, War Memoranda

Centrifugal: proceeding or acting in a direction away from a center or axis

Rapport: relation marked by harmony, conformity, accord, or affinity

Sirius: a star of the constellation Canis Major that is the brightest star in the heavens —called also Dog Star

Capella: star of the first magnitude in Auriga (star found between Perseus and Gemini)

***All definitions found from merriam-webster.com***

He is speaking about the universe as if it were a ship with the forces of space. Centripetal and centrifugal are exactly the opposite of one another, signifying that Whitman is experiencing the opposite sensations within one event.

He also experiences that rapport of the sun, moon, earth, and constellations; that is the combination of all of these atrological factions together at one time.

Whitman continues to ask questions regarding the messages that constellations (specifically Sirius, the Dog Star, and Capella, the constellation found between Perseus and Gemini) are sending to him. He asks if there is a central “heart” to everything in the universe.

Perhaps Whitman believes that the ship is a representation of humankind and those that are on the ship are the central heart that keeps the ship sailing.

Centrigual: proceeding or acting in a direction away from a center or axis (merriam-webster.com)

Rapport: relation marked by harmony, conformity, accord, or affinity (merriam-webster.com)

Now, let’s look at the title Fancies at Navesink. This is literally Whitman’s thoughts as he looks out on the New York Bay. So far, we have a man metaphorically looking out on his approaching future and literally looking out on a bay.

I think we’re ready to look at the actual poem now. “Then last of all” (1) denotes finality, finale, end, conclusion, which I take to mean the conclusion of the day and this subsection of poems.“Caught from these shores, this hill” (1) refers to the sea-side mountain of Navesink, which is an entrance to New York Bay. “Of you O tides,” (2) the tides are the only “you” in the poem, and are the source of power, mystery, and are approaching the speaker, catching him “from these shores, this hill” (1). “The mystic human meaning:” (2) is a phrase modifying the “you” as in “O tides” and therefore defines the tides as a mystery, which the speaker doesn’t understand, but recognizes its meaning, its importance for him and all human kind. “Only by law of you,” (3) indicates human meaning comes from an inhuman, mystical, natural force. “Your swell and ebb,” (3) are traits of the tide and serve as further proof “you” is indeed the tides. “Enclosing me the same,” (3) is basically the speaker saying “I don’t understand it, but it’s unstoppable, so I might as well deal with it.” “The brain that shapes, the voice that chants this song” (4) closes the poem without trying to identify the “mystic[al] human meaning” (2).
Bottom line: Whitman is saying, “The mystical human meaning is part of my life. It has enclosed me, invaded my thoughts and inspired me to form and sing a song about it. My song doesn’t try to explain the meaning; I don’t understand it. I’m simply writing of its existence and inevitability.” This poem is a musing about unanswerable questions and the sense of awe those mysteries invoke in the poet. It fits perfectly in a section of poetry about a poet who is rapidly approaching his seventieth birthday–and, eventually, death–and has questions he can’t answer.