_Rise Up Singing_ correctly attributes it to Mackay, but gives a much abridged & somewhat changed version. It is interesting to compare two couplets that occur in both versions:

CM:
Twice a thousand miles behind us, and a thousand miles before,
Ancient Ocean heaves to bear us to the well-remembered shore;
New-born breezes swell to waft us to our childhood's balmy skies,
To the glow of friendly faces, to the light of loving eyes.

RUS:
Full 10,000 miles behind us & a thousand miles before
Ancient ocean waves to waft us to the well-remembered shore
Newborn breezes swell to send us to our childhood's welcome skies
To the glow of friendly faces and the glance of loving eyes.

I always wondered about that second line in RUS: Anyone waiting to be wafted by waves will have slow going. "Heaves to bear us" makes sense: It is as if the ocean were carrying us on its shoulders. On the other hand, I think the third & fourth lines have improved in the folk process: "Welcome" is more to the point than "balmy", and "glance" is more vivid & less hackneyed than "light".

On the whole it seems to me that that folk process has done well by this song; it has gotten rid of a lot of bombast, and added that wonderful couplet about the sails full of snow (missing from RUS as well).