I believe the poem expresses a constrained sorrow at the loss of a friend and time. The lines referring to the ever breaking sea, the fisherman’s boy, the stately ships, ect… All show how thepermanence of the world around and how it remains unaffected by the poets personal grief. The touch of the hand etc is a reference to the speakers melancholy: he remembers someone who hasdied a and grieves.
The meter of the poem, I think the pattern of stresses and unstressed syllables is all over the place. Almost every line has three stressed syllables.
I agree with moriama, the poet Alfred Lord Tennyson is looking at the ocean and is looking for a way to express his grief. He sees his sister playing with a fisherman’s son and a sailor singing but it doesnt seem to help cheering him up. All he seems to remember is the voice of his dead friend, that he wishes was still alive so he could talk to. The ocean waves keep breaking on the ocean and time keeps moving on but the poet can never go back to when his friend was alive.