It's one of the Clancy's doing the Intro - probably Liam (definitely not Tommy Makem). The Clancy's are from the border of Waterford and Tipperary and would have spent a lot more time in New York than they ever spent in Dublin, so may be a bit challenged when it comes to Dublin geography. Liam always did a good line in patter between songs and I'd say he was never one to let the truth get in the way of a good story. Anyway Kilmainham is nowhere near the Royal Canal, so Liam got it wrong.