Harold Augustin Calahan (November 7, 1889 – November 25, 1965) or H. A. Calahan was a lieutenant commander in the United States Navy and an author on sailing.
[1][2] He was born in Brooklyn and attended Columbia University for his B.S., M.S.
In 1917 he was working at an advertising agency, and he later married Gladys Britton.
[3] He died of a heart attack in 1965 in Port Chester, New York, and was buried in Arlington National Cemetery on November 30, 1965.
He strongly argued that Stevenson had in mind to write such a story.