I checked Black Betty in the Digital Tradition and it's not Leadbelly's version. My dad learned the song from Leadbelly himself many years ago, this is what I remember of it:

Hey Black Betty Bam da lam

Hey Black Betty Bam da lam

Black Betty had a baby, Bam da lam

Black Betty had a baby, Bam da lam

Dat thing gone crazy (x2)

Dat thing gone crazy Dat thing gone blind

Was the captain's baby Warn't none of mine

Hey Black Betty (x4)