I take your point, Dead Horse. But perhaps originally some shantyman, looking for a new refrain the crew could work to for a shanty tune which had just come into his head, might echo an order he had just heard the bosun [or on a merchamtman more probably the mate] yell out, of 'Go down below, you bloody red-roses", to be taken up by the hauling or heaving crew as their chorus: I mean, all shanty words have to come originally into the shantyman's head from somewhere, don't they? Like I say: just [another] thought...