Sunset and evening star, And one clear call for me! (1-2)
This just might be one of the most mysterious moments in the poem. Having read the whole thing, we can see how the imagery might refer to death. But who's calling our speaker? And what are they calling him to? Is it the pilot, from the last stanza?
And may there be no moaning of the bar, When I put out to sea. (3-4)
The speaker says he will put out to sea, almost as if he will voluntarily cross the boundary between life and death. The speaker's active role here suggests that he accepts death, that he willingly "puts out to sea." Hey, maybe he's his own pilot.
Twilight and evening bell, And after that the dark! (9-10)
The word "dark" is a wee bit worrisome here. The poem's last stanza talks about something resembling an afterlife—the speaker hopes he will meet God (the "Pilot")—but here it kind of seems like there is nothing after death but dark, a big giant blank.