"hemp or cotton canvas used in making ships' sails," c. 1200, from sail (n.) + cloth (n.).
Entries linking to sail-cloth
sail n.
"piece of shaped cloth spread so as to catch the wind and cause a vessel to move in water," Old English segl "sail, veil, curtain," from Proto-Germanic *seglom (source also of Old Saxon, Swedish segel, Old Norse segl, Old Frisian seil, Dutch zeil, Old High German segal, German Segel), of obscure origin with no known cognates outside Germanic (Irish seol, Welsh hwyl "sail" are Germanic loan-words). In some sources (Klein, OED) referred to PIE root *sek- "to cut," as if meaning "a cut piece of cloth."
As "a single ship or vessel" by 1510s. To take the wind out of (someone's) sails (1888) is to deprive (someone) of the means of progress, especially by sudden and unexpected action, "as by one vessel sailing between the wind and another vessel" ["The Encyclopaedic Dictionary," 1888].
cloth n.
"woven fabric, pliable stuff made of intertexture of threads or fibers," Old English claþ "a cloth, sail, cloth covering, woven or felted material to wrap around one," hence, also, "garment," from Proto-Germanic *kalithaz (source also of Old Frisian klath "cloth," Middle Dutch cleet, Dutch kleed "garment, dress," Middle High German kleit, German Kleid "garment"), which is of obscure origin, perhaps a substratum word.
As an adjective, "made or consisting of cloth," from 1590s. Meaning "distinctive clothing worn by some group" (servants of one house, men of some profession or trade) is from 1590s, hence The cloth "the clerical profession" (1701).