And I mused on competing annotations for "weft" in the stanza
The Sun came up upon the right,
Out of the sea came he;
And broad as a weft upon the left
Went down into the sea.
I gave this one to Fry, with the proviso that I didn't have my copy of John Livingston Lowes's The Road to Xanadu on hand. Well – I guess I wrote too soon. (Still haven't found either of my copies of Road, by the way; one of the girls must have eaten them. The library copy, heaven knows, is half-eaten.) Lowes, whose book (published in 1927, mind you) tracks down the source of practically every word in the "Rime" & "Kubla Khan," has no fewer than nine pages on "weft," & makes it abundantly clear that the word, which STC could have come upon from any number of sources in any variety of forms (waffe, weffe, waif, waift, whiff, whift, wheft, wave, waft, weft), must be taken in the nautical distress sense.
Fry writes, "weft: Threads carried by a shuttle across the warp," while Richey & Robinson [of the New Riverside Editions Lyrical Ballads] give us "weft: a large flag used on ships for signaling distress."
So the next question: how did Paul Fry (William Lampson Professor of English and Master of Ezra Stiles College at Yale University) manage to so howlingly mis-gloss the word, when he had a voluminous commentary at hand in one of the foundational texts of Coleridge criticism? Let's face it, "Threads carried by a shuttle across the warp," which reads like the first definition of "weft" in a standard college dictionary, just doesn't cut it when you're annotating an 18th-century poem.