As I was saying,

next brings in a couple of cliche' lines, and ends with something unrelated to anything that's gone before.

It's partly free improvisation, partly a "re-telling" of another song, and partly the importation of familiar lines from elsewhere.

The repeated lines (unlike the couplets of chantey books) are typical of field-recorded chantey singing; Carpenter's chanteymen, for example, rarely use couplets.