Family roots in Norway

I am trying to trace my father's family roots. I found my grandparents : Alexander and Hilma Andersen, listed in the Passenger Search files of the Ellis Island organization as passengers on the SS Norge arriving in NewYork on May 23,1893. From your Ship Index I found that the SS Norge departed Christania on May 8, 1893 en route to Christiansand and New York. Hoping to find more info in the Digitalarkivet, I paged thru the Emigration Registers for Oslo, Christania, and Christiansand for 1893 withou finding my grandparents listed. At this point, I don't know where to turn. Since my father was born on New Years Eve in 1893, I know that Hilma must have been pregnant when they left Norway. A cousin thought that they lived in Drummond (Drammen??). Any help would be appreciated. Unfortunately, I don't speak or read the language. Geoge Anderson