Joe,

From above-cited article:

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The spelling of chanty has not been standardized to date, but two spellings are very common and now offered by the online Oxford English Dictionary (“shanty | chant(e)y, n.2,” http://www.oed.com/view/Entry/177492). The first, shanty, appears to be the most common globally, and is now practically standardized in Commonwealth English. A large number, especially Americans, use chantey. Spellings with ch are maintained in the United States through its use by such archives and educational institutions as the Library of Congress, the Smithsonian Institution, and the Mystic Seaport Museum, [[to which we could add Peter's organization, San Francisco Maritime Park]] just as it was kept current through the works of related agents like Alan Lomax, Robert W. Gordon, and Folkways Records. The two communities of living singers that learned their traditions exclusively through oral tradition and in the context of labor, retired African American menhaden fishermen of Chesapeake Bay and whalermen of St. Vincent island, generally present their performances with the spellings chantey and shanty, respectively.
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