Crossing the Bar

I'm not sure if I just don't have a "poet's mind" (Well actually I am pretty sure I don't) or if I just don't quite see things the way these people do but I always have no idea how they would decide to write the poems they do. I mean really who is just sitting at home, writing some poetry, when they think, "hey I'll write about death but I'll use a sand bar to represent it." I mean I can understand a lot of kind of crazy comparisons to death but a sand bar? that one I don't really understand the thought process. Regardless of whether I would have thought to write about a sandbar or not the poem does, kind of, although I regret to say it, make sense. I mean he says that he's leaving (dying) and so he's going out to sea. Then to further represent dying he's going to cross some sand bar. The water gets shallower and all kinds of other symbolic stuff and it's kind of a long and involved process. Much like death can be. Overall this poem seems to me to be just another death comparison.