A note from (arguably) pre-shanty days --

This is a supposedly true story, "My Adventures (Part VI)", by an "O.P.B." from Connecticut, aboard a ship the TRAVELER (slave ship disguised as merchant ship) out of New York and, at this point, at Rio, Brazil. It's in _The Rural Repository_ (Hudson, NY: William B. Stoddard) Vol. 12(23), 16 April 1836.

I believe the period described in the account is the late 1820s.

There is a section where work orders are given. They are being pursued by a schooner. Pg. 180:

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'Ship them then at once. Man the capstan bars, my men. Send up that drunken fifer, Tom, and let him play Yankee Doodle. That's it. Round with you men, round with you cheerily. Heave, and she must come. Walk her up, my lads, walk her up. What are you doing there you black rascal, leaning your whole weight on that bar. Cook, steward, come out of the cabin, you yellow, sneaking scoundrels and bear a hand on deck here. By the Lord, the schooner's hoisting her topsails. Do you mean to lose this fine land breeze, you long, lubberly villains. Do you mean to sleep in jail to night, you poor, good for nothing devils ?' This last exhortation seemed to have the desired effect, and in a few minutes the anchor was at the larboard cathead, and amid the general confusion Captain Talbot and his bo.us crew came aboard. 'Man the topsail halliards, hoist away' and up went the topsail yards to the inspiring tones of the fife, the sails catching the fresh breeze from the land, and the ship already beginning to feel its influence, and dashing the smooth water in mimic waves from her bows.
//

So, there is a conspicuous absence of singing mentioned. Only the fife is used.