If we know one thing for sure about the speaker of "Crossing the Bar," it's that he's about to die. It's not clear if he's really old, or just sick, or some sort of old, kooky clairvoyant, but somehow he knows that death is just around the corner. He keeps talking about putting out to sea (4, 12, 14-16), which sure sounds like a metaphor for death if we ever saw one. All the images of sunset and evening (1, 9-10) and sleep (5) strengthen the impression that death is coming for the speaker.
Even though he's close to death, the speaker doesn't seem at all afraid. He doesn't want anybody to weep and moan (3, 11) because he's pretty confident that good stuff is waiting for him just around the bend. What good stuff? Well, in the poem's final stanza, he talks all about meeting his "Pilot face to face" (15), which tells us that he's a believer, and he's ready to meet his maker.
You've gotta hand it to our speaker. He's about to kick the bucket, and yet he still manages to look on the bright side.