Five short lines tell the story of a navy's collapse, and they do it mostly through sound. The repeated f's and the clipped, clustered consonants of "fair fleet fell" and "frigates," "broke," "creeping" give the opening a slippery, tumbling feel, as if the words themselves are sliding downhill. A once-admirable fleet "fell into vice," and the poem never says exactly what that vice was.
The speaker says "us" and "did us in," so they seem to belong to the fleet, looking back on a ruin they were part of. The tone is rueful and a little wry rather than angry. The ending is the sharpest turn: the sea outdoes the crew "in business and in bed," which suggests that the ocean is greedier and more seductive than any sailor. Whether the vice is commerce, lust, or both is left open, and the "scuttle" (a hole cut in a ship, or the act of sinking one) hints at a self-inflicted wreck. The mood is compressed, mocking, and faintly doomed.