A ferry slips out of thick sea fog into moonlight, and the speaker, watching from among the passengers, wonders which of them will make love tonight. The question sets up two answers. On the deck, young, lean, brown-skinned lovers kiss, their hair blowing together. They are the obvious, picture-perfect answer, the sort of couple we expect to see in a poem about desire.
Then the poem turns to a heavier, older pair in the snack bar: a fat grey man and his shabby wife, eating potato chips. Nothing glamorous happens, yet their feet touch under the table, he brings her coffee, she smiles and strokes his hand with a rough finger. The speaker doesn't say it outright, but the small gestures suggest that intimacy is just as alive here, and perhaps deeper.
The mood is quiet, tender, and a little wistful. The fog lifting and the phrase "We're all coming ashore" give a sense of arrival, with everyone, young or old, heading toward the same human need for closeness.