In poetry, there is usually one controlling metaphor and a tension that is set up between two ideas. Alfred Lord Tennyson's poem, "Break, break, break," sets up such a tension between the permanence of Nature and the transitory quality of human life.
In his typically melancholic tone, Tennyson recounts his grief for the loss of a loved one, set against the permanent and lasting images of the sea's waves that eternally "break, break, break." Yet, with the images of "cold gray stones" against which the sea breaks, there is a metaphoric connection between the speaker's heartbeat and grief with the sea's waves against the stone.
However, as the speaker watches the activities on the sea, he perceives more permanence in the fisherman's boy, the sailor, and the stately ships that will continue their activities though his friend has died. Notice that Tennyson uses common nouns for these people, thus indicating that another boy will replace the "fisherman's boy," another sailor will replace "the sailor." But, in contrast, there is no replacement for the "vanished hand/And the sound of a voice that is still!"
Interestingly, while there is a clear anapestic meter, which is predominately trimeter, (two weak stresses followed by one strong stress as in the phrase in a car, written 3 times) to this poem, some lines vary in meter. These departures from a strict metrical norm contribute to the meaning by pointing to the sharp pangs of anguish that the speaker experiences. In fact, the refrain, "Break, break, break," can be interpreted both as the sound of the waves and the sound of the speaker's broken heart.