Explain how Whitman develops an extended metaphor in his poem

I just completed this one-- This is how I take it, and I hope you can build something off of it:

As metaphors are similes without like or as, the entire poem is a metaphor in the sense that it's representing the end of the Civil War, but describing it as a ship and it's captain.

He shows the ship returning to port, how people are excited and cheering for the victory and the end of the war, but how the narrator is mourning the loss of his captain.

This easily represents Lincoln's death, which is an important aspect of the war and poem.

Sample Response: Whitman begins by comparing Lincoln to the captain of a ship and his army to a boat. The metaphor honors Lincoln and the army for helping defend and win the idea of freedom. Whitman ends the poem by saying that Lincoln, the captain, has died. The army and the United States have lost an important leader.

Explanation:

the writer needs to avoid using abbreviations and check spelling before sharing.

what are the options?