Tracking down this copyright claim was quite a conundrum -- I don't think it's the artist we're searching for here, but I'm not sure. This will be a bit circuitous, but bear with me.

A fellow named Walter "Hats" McKay (pictured here - Experimental Musical Instruments, June 1995) published several songs from while living in San Francisco in the 1910s-1920s, but I couldn't find one by the name "Midnight on the Ocean." Texts I did find include Don't Send Me Back To Dublin, If Ireland Was Only Like Hawaii, and Samoa. [The Hawaiian theme is the connection to the man pictured]. I'm not sure if this is the same fellow GUEST refers to above.

The book which fhbals referenced in the original post, Fever, p. 198, by Peter Richmond, attests that the song in question was copyrighted in the 1932 edition of the US Copyright Catalog. I found no song by that name under either McClintock (H.K.) or McKay (or even a song attributed to a Hats McKay), though there were five other titles to his name, including Cheese Song, My Last Old Dollar, Sweet Betsy From Pike, When it's Time To Shear the Sheep, and a collection entitled "Mac's Songs of the Road and Range."

This last bit is the linchpin. Gavin also provides the teaser that the song was actually published by Sterling Sherwin. Sherwin's name was also featured on the song book (and in the copyright catalog), and upon finding a list of titles in the songbook (link), "It was midnight on the ocean" was included in the collection. I haven't found a version of the book available to read online.

Further confirmation aside, that is indeed the same Haywire Mac McClintock as the folksinger. Where the appellation "Hats" comes in is to be determined.