Tennyson loved to talk about sailing the ocean. And Tennyson loved his perfect meter. Check out "Ulysses" and "The Lady of Shalott" for more watery, metered masterpieces.
"Crossing the Bar," a poem that at Tennyson's request has been the epitaph for his poetic output ever since he published the poem in 1889, is no exception. The poem is full of oceanic imagery like the bar (3, 16), the sea (4), the tide (5), the deep (7), the flood (14). In Tennyson's poetry, the ocean is associated with adventure, the unknown, and death, all three of which seem to be at play in this poem. In this case, the speaker embarks on his final journey; he leaves the harbor of life—crosses the bar—and heads out for the great, unknown ocean that is death.