Boab, if the original Mingulay Boat song was written by Hugh Roberton, then he must have been a few hundred years old when he did it.
Na it's one of these songs which has been taken from the tradition and sort of sanitised for choral use, probably in this case by Marjory Kennedy Fraser.
MJF maintained that she was saving songs which would otherwise be lost but it is interesting to note that none of the original songs that she changed have been lost to the tradition in their original form.