Yes those words are by Hugh. S. Roberton.. it is a copyright work, but people assume trad. on the whole thing. The words and story of the song are well known on this site and reproduced elsewhere, Hugh S. Roberton died in 1952, so in UK law it will be fully out of copyright anyway, at the end of next year.

My late father recorded it as a single, with seagulls and waves on the intro and outro for Grampian records in 1965. Godawful version really, with an accordion, plinky plonk piano and barely audible snare.