It's a one verse fragment of a shanty collected by Cecil Sharp in 1914. Don't ask what the shanty was because it is actually irrelevant. That's a stupid thing to say - people are bound to ask! OK, its Blow away the Morning Dew / Advertised in Boston / etc. - so that doesn't help at all! This particular shantyman had a habit of giving Sharp lyrical folk songs texts to otherwise familiar shanties - but I'm not going into why that was at this juncture.

It's certainly got me stumped as to where it comes from!