To me the term new shanty is a bit of a contradiction - a shanty, ie a song made for a job of work must have by definition a cut-off up to the point when sailing vessels were used for commercial shipping as opposed to sail training. Anything after this can only be a sea song written in the idiom of a working song. Even in the days of cpommercial sailing vessels there were contempory songs gthat were used for work, particulalry pumping songs.

Probably a subject for another thread - the boundary between popular songs being used at sea, and popular songs being parodied/sailorised sufficiently to be classed as a bona-fide shanty.