The "Boating on Lough Ree" song is unrelated to Molly Bawn/Polly Vaughan etc etc. I think its a lament for a lost love, by John Keegan Casey (aka Leo). Tim Dennehy recorded it recently. I'll check out his version.

Regards

p.s. The Lough Ree in question is the one on the River Shannon, north of Athlone.