1918        Howard, Henry. "Manning the New Merchant Marine." _Pacific Marine Review_ 15 (August 1918).

By the Director of Recruiting, U.S. Shipping Board.

Section on "Training Merchant Crews" gives the daily schedule on training (steam) ships. 6-9pm included recreation, about which it says,

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Recreation includes singing, for each ship is supplied with a piano. The musical program includes old-time chanties, in which the young men are instructed by a veteran deep-water chantie man.
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I would guess that the "veteran" was Stanton King – though it seems like more than one "veteran" would need to have been recruited.