But surely no one is suggesting changing the spelling
Oh no, I don't mean in our discussion, I meant re: the act of RR Terry back in 1915, and the subsequent similar decision of Joanna Colcord. As discussed above, though there was no "standard" spelling, "ch" had emerged by that time as the most common -- common enough that they were worried about mispronunciation.

Even though sailor-commentators had earlier spelled it most often with "ch", these authors decided to change it. Mind you, I do understand that if it was not completely standardized, it was not a "change" per se. But we've enough references with "ch" to argue that "ch" had indeed been customary.

Now, the point that "However you spell it, it's still the same word" is well taken, naturally -- though I don't think we need to resort to characterizing sailors as illiterates or people who never cared about any such things.

But the question still remains, one where spelling IS relevant: why did the early writers spell it with "CH"? There must have been some reason. Either:

1) It was at first pronounced with the affricate sound (as in "church")
or
2) It was pronounced (always) with the fricative sound ("shut"), but...for unknown reasons, they felt this sound should be represented by /ch/.
If #2, what were those reasons? Possibilities:

-- There really was some French influence going on. The setting in the French-Creole areas of the South has been cited.
-- It was done to mark off the word as somehow belonging to a special class, be it "foreign," "special" or whatever. Like the way "Chandigarh" (mistakenly) fits into such a "class" of words in my mother's mind!
-- There was some existing term, the same or similar, that already favored that spelling. I have already mentioned the way "chaunt" was used as a way to label songs of a perceived AFrican-American style, while admitting I have no knowledge about why that was so.
-- Visually , they wanted to maintain the connection to "chant," even though it may have been diff
-- Something to do with the backgrounds of the people who were writing
-- ???

1855 Nordhoff: "chanty-man", "chants"
1867 Clarke : "chanty-man"
1869 Alden: "shanties"
1883 Luce: "chanty-song"
1886 Davis and Tozer: "chanties"
1888 Smith: "chanties"
1893 Hill: "shantier" "from French chanteur"
1903 Webb: "chanties"
1904 Bradford and Fagge: "chanties"
1906 Bernard: "Chanties"
1906 Hutchinson: "chanties"
1906 Masefield: "chanties"
1909 Whidden: "chanties"
1909 Williams: "chanties"
1910 Whall : "shanties"
1914 Beckett: "shanties"
1914 Bullen: "chanties"
1914 Sharp: "chanteys"
1915 Terry: "shanties"
1915 Derby: "chanties"
1915 Lubbock: "chanty"
1915 Meloney : "chanty man"
1916 Sharp et al : "chanties"
1917 Brown : "shanties"
1917 Robinson: "chantey man"
1918 King: "chanties"
1920 Wood: "chantey"
1920/1 Terry: "shanties"
1924 Colcord: "shanties"
1924 Frothingham: "chanteys"
etc.
I realize they are a little meaningless without full context cited.