"Day after day, day after day,..."
See in text (The Rime of the Ancient Mariner in Seven Parts)
Coleridge uses two literary devices in this stanza to emphasize the length of time that the ship was without wind. First, the repetition of "day after day" gives the impression of a lot of time passing by. Second, the simile in the last two lines where the ship is compared to a painting also reinforces the idea that the ship is static and can't actually move at all.