The sea looms large in this poem, and shows up in almost every couplet. The lover is closely related to the sea. In fact, she seems to be powerful, terrifying, and beautiful—just like a stormy sea that can swallow up even the bravest sailors. The sea is a big deal for Neruda in almost all of his poetry, so it's good to get acquainted with it here.
Line 2: This is part of the first couplet , and sets the stage for the rest of the sea metaphors that will follow. The river is lamenting… and so is the speaker! And we know all rivers lead to the sea, so we will see which sea this river leads to. (Oh, the suspense!)
Lines 3: The wharves are, like the river, a place where the sea begins. he speaker compares himself, this time, to the abandoned, lonely wharves. He's always approaching the sea, but never seems to dive in.
Line 6: Okay, them's fighting words! The speaker can be seen calling his lover a pit of debris and the cave of the shipwrecked. She's like a mighty force that destroys the brave sailors who decide to take her on. (Of course, if we want to give him the benefit of the doubt, he could be referring to his own heart. What do you think?)
Lines 9-10: And the hits keep coming. Now the speaker lays it out. The woman was such a gigantic figure in his life that metaphorically she seemed to swallow up everything. (Just like the sea, get it?)
Line 12: The love the two characters in this poem shared was hot, and the speaker compares it to a lighthouse using a simile. And where do lighthouses live? On the shore, where the rocks are dangerous for sailors. What does this say about their relationship? Hmm?
Lines 13-16: Our speaker's still stuck on this whole sinking idea. Through metaphor, the poem compares himself to two figures, both of which brave the sea and, unfortunately lose: the pilot, and the blind diver. The speaker is like one of these conquistadors who end up sunk at the bottom of the sea, or, in this case, brokenhearted.
Line 43-46: Here we go again! The pit of debris is back, sucking up everything in its path and drowning it. The woman is strong, like a sailor, and could sing through the storms, but it seems as though our speaker had no such luck.
Line 49-50: The speaker seems to be comparing himself to the diver, the slinger, and the discoverer again, all of whom went down in the sea of love.
Lines 53: This image, of the sea being buckled to the shore, reminds us of those first lines of the speaker being like the river. Just as the sea can't be separated from the shore, it looks like he's unable to separate from his memories.
Line 55: The repetition of this lonely line, from way back in line 3, drives home the image of the loss and loneliness that the speaker feels as he looks out, or back, on the sea and his past.