lyrics by Peter Mayer
tune ("Hyfrydol") by Rowland Prichard.
Peter Mayer's tune differs from the traditional hymn in that the last three notes are drawn out to three beats apiece; traditionally they get only one. Additionally, in the last verse during the words "sky my sailor song" he holds the Em chord while singing G for the entire line.
I play this in C or D because it's easier for me to sing. Your harp may sing it better in G. Here is a video of me performing it in D.