The cruel murder ballad Pretty Polly is a shortened version of The Cruel Ship's Carpenter / The Gosport Tragedy (Laws P36A). Although no clear line between both ballads can be drawn, the Traditional Ballad Index tends to call the piece The Cruel Ship's Carpenter if it includes the ghost and Pretty Polly if it doesn't.

“Polly, pretty Polly, come go along with me,
Polly, pretty Polly, come go along with me,
Before we get married some pleasure to see.”

Thanks to Mainly Norfolk.