IMO Authenticity with Shanties is only achieved, if they are sung in a nmanner that they can be worked to...

No. It's not "can," would, could or should. Authenticity, is actually leaving in the actual work that the verse is leading and the chorus is working. Grunts, groans and all the rest. Metrology, eg.: a tape measure, stop watch, strain gauge, data recorder &c shall also be considered sporting.

It's not why folk go to the club or buy song books.