Alden, Harper's Mag. (July, 1882):

"Quite as popular as Stormy was another mysterious person — Randso. Of this person it is 'alleged in an unusually coherent narrative song that 'he was no sailor"; that, nevertheless, 'he shipped on board of a whaler,' and as 'he could not do his duty,' he was brought to the
gangway, where 'they gave him nine-and-thirty.' Obviously Randso was not a model for sailors.

O Randso was no sailor,
Ah, Randso, boys, ah, Randso.
He shipped on board of a whaler,
Ah, Rando, boys, ah, Randso."

(Much like Adams, but the "Randso" spelling suggests an independent source. And the "ahs" might be the remnant of an earlier "Lorenzo" - or not.)

C. Fox Smith, "A Book of Shanties," (1927) is nearly identical to Davis & Tozer. She concludes (from nothing) that the "real" Ranzo "may have been a Russian or Polish Jew named Ronzoff."