Having read Ferber's novel and seen both the 1936 and 1951 cinema versions, as well as the live theater revival of the late 1990s (saw it in Boston) I can say that the 1936 film has captured the true spirit of Ferber's original intention. She was trying to illustrate, through the vehicle of "show-biz" as reflected in the circa 1885-1927 biographies of players and owners of a river showboat, the changing American scene, including race relations, the institution of marriage, unemployment, alcoholism, paternal/spousal obligations, etc. The most glaring change from the novel, is that in Ferber's book, Gaylord deserts Nolie in Chicago and never surfaces again. Hammerstein's libretto has the two reconcile. The 1936 film is more true to Ferber's intention, since it is uncertain regarding the effects of Gaylord re-entry into Nolie and Kim's life. The 1951 film has Gaylord fully integrated with the life aboard the Cotton Blossom, though the time frame is quite fuzzy in this version. We might assume that Gaylord and Nolie somehow resume their relationship, but in 1936, the re-union aboard the Cotton Blossom is left up in the air.
I believe that Edna Ferber was still around to have some in-put or oversight for the 1936 film, but it is unlikely she would have approved of the liberties taken in 1951---including the absurdly huge Titanic-proportioned Cotton Blossom of the later film. The showboat in the novel was barely large enough to contain some crew cabins for family and cast and a central theater seating perhaps a couple of hundred guests per night at most.
I believe that Edna Ferber was still around to have some in-put or oversight for the 1936 film, but it is unlikely she would have approved of the liberties taken in 1951---including the absurdly huge Titanic-proportioned Cotton Blossom of the later film. The showboat in the novel was barely large enough to contain some crew cabins for family and cast and a central theater seating perhaps a couple of hundred guests per night at most.