"Crossing the Bar" and "Dover Beach" are two basically unlike poems that have something in common. Both poems have different themes, but they both use the same metaphor. The ocean is metaphorically used in the two poems.
In "Crossing the Bar", Tennyson uses the metaphor or the ocean to describe the barrier between life and death. In the poem, the speaker heralds the setting of the sun and the rise of the evening star, and hears that he is being called. he hopes that the ocean will not make the mournful sound of waves beating against a sand bar when he sets out to sea. Rather, he wishes for a tide that is so full that it cannot contain sound or foam and therefor seems asleep when all that has been carried from the boundless depths of the ocean returns back out to the depths. The speaker announces the close of the day and the evening bell, which will be followed by darkness. He hopes that no one will cry when de departs, because although he may be carried beyond the limits of time and space as we know them, he retains the hope that he will look upon the face of his pilot when he has crossed the sand bar.
In "Dover Beach", Arnold uses the ocean as a metaphor of the sea and faith. This is a poem about sea and a beach that is truely beautiful, but hold much deeper meaning than what meets the eye. When the sea retreats, so does faith, and leaves us with nothing. In the last nine lines, Arnold wants his love and himself to be true to one another. The land, which he thought was so beautiful and new, is actually nothing. "Neither joy, nor love, nor light." In reality, Arnold is expressing that nothing is certain, because where there is light there is dark and where there is happiness there is sadness.
The ocean is used as a metaphor in "Crossing the Bar" and "Dover Beach". The two poems are unlike but have something in common. The ocean represents something great and represents even greater in the two peoms.