This song is entitled 'Mandela' and written by Danny Hannon who lives in the Bronx, NY. One of the people (maybe 'the' first) he gave it to & who recorded it with her band 'Morning Star' was Mary Courtney of Co. Kerry, now living in the Bronx. She sings it better than anyone I have ever heard. She always credits Danny Hannon, and tells everyone to visit him on MetroNorth where he works as a conductor!

Someone posted her recording to Youtube:
http://www.youtube.com/watch?v=tR4qklI9v_s

It is also on her solo album 'Sceil Eile':
http://www.cdbaby.com/cd/mcourtney

I think the name of the other song that MikeJC referred to about the sailor and the ring is 'No tengo Mas que Darte' which Mary sill sings regularly. Her schedule is on Facebook:
http://www.facebook.com/home.php?#!/profile.php?id=1690580722&ref=ts

    http://www.cdbaby.com/Artist/MaryCourtney1
    http://www.cdbaby.com/cd/mcourtney3
    http://www.sonicbids.com/marycourtneymorningstar