I was the person who made the original query. The song I am looking for a tune for is not the Thomas Moore one, but one claimed to have been translated from Scots Gaelic, although more probably written by some Scots poet.

I have the complete words and some history, but do not know if there is a tune for it.

It begins thus:

Fair these broad meads - these hoary woods are grand; But we are exiles from our fathers' land.

Listen to me, as when ye heard our father Sing long ago the song of other shores - Listen to me, and then in chorus gather All your deep voices, as ye pull your oars.