There also seems to have been occasional self-aware composition and subsequent memorization. That's how I account for the unique set of lyrics sing to Ivan Walton by Great Lakes sailors Harry and George Parmalee in 1932:
Oh, poor old Reuben Ranzo, Ranzo, boys, Ranzo! Oh, poor old Reuben Ranzo, Ranzo, boys, Ranzo!
Oh, Ranzo came up to the Lakes, Where sailors live on prime beefsteaks.
Now it's a widespread rumor, That he shipped aboard a schooner.
But Ranzo was no sailor, For Ranzo was a tailor.
The Old Man set him wheeling, For Ranzo was appealing.
But he could not rock or shake her, For Ranzo was no sailor.
His course was up Lake Erie, But he grounded on Point Pelee.
The Old Man loud did curse him, Oh, how the Old Man cursed him.
He kicked him to the galley, With pots and pans to dally.
When they came into a grain port, The Old Man cut his sailin' short.
But Old Ranzo became the owner, And the Old Man now works for him.