Finbar and Eddie Fury have an album [which I possess somewhere in my chaotic music library}which contains 'the Curragh". Perhaps you may be lucky and get a pointer. Meantime check Robert Burns "the Winter it is Past". Maybe Michael can point to the facts, but this is obviously either a Burns original from which "the Currach' has arisen, or conversely is Burns' adaptation of the Irish song; not unusual for Burns---he did "doctor' quite a few old songs for publishing.