Hugill was prone to assumptions which, on examination, do not stand up.
One of these is a statement, in "Shanties from the Seven Seas," in his discussion of "Good Morning, Ladies All," or "Roller Bowler."
Without foundation is: "The line 'Good morning, ladies all' brings us to two more shanties which include this fairly obvious Negro phrase, and I feel certain phrase, and I feel right in saying that any shanty including it can be said to be of Negro origin. His only reference is a minstrel song of the 1850s and the statement with it that Here is "a genuine Negro song given by a southern slave owner."

The phrase in known in both England and North America, used to greet a group of female students or other group of women. An example from England is found in a play for teenage girls by John Spurling, presented at Cheltenham Ladies College, "Racine at the Girls' School," where the young women are met with the greeting from Racine, "Good morning, ladies all!"
Other examples may be found in google search of literate English usage.

Robert C. Leslie, in "Old Sea Wings, Ways and Words in the Days of Oak and Hemp," , London, 1890, Chapman and Hall Ltd., describes the sailing of an American Black X ship from St. Katherine's Docks, bound for New York, p. 233: "Yankee seamen (almost an extinct race now) were then noted for their capstan chants, and the chorus of "Good Morning, Ladies All," swells quaintly up at intervals above the other sounds."" [Leslie was speaking of the 1880s]

Terry learned the song from "Northumbrian sailors" He speculated on a "more southerly" origin, but no more than that. In his version, the sailing is from London docks to New York town, the course of the sailing described by Leslie.
Perhaps the chantey is of Black X origin.

Leslie's book is reproduced in full here:
http://www.archive.org/stream/oldseaswingsways00leslrich/oldseaswingsways00leslrich_djvu.txt