These lines signify the victory in the civil war of the Union.
These lines by Walt Whitman were eulogizing Abraham Lincoln after his death.
These lines start by relating that the battle that they were fighting in his leadership is now won,
The battle here is the civil war.
This is described by the narrative strategy of metaphor in which the ship is the Union force and the sea is the war and the war was now won but the captain of the ship who is supposed to be Lincoln is no longer there so the victory does not seem to him complete.
under his wing Eliza Doolittle away from the streets. Her job when she was on
the streets is to peddle her wares as a flower girl. After taking Eliza under
his wing, he taught her how to speak English accurately coupled with a
civilized accent and also taught her how to behave in a sophisticated manner.</span>