In 1929, the United States Interocean Canal Board approved out a two-year detailed study for a ship canal route, known as the Sultan Report after its author, the United States Army engineer Colonel Daniel Sultan.
Amerikanska Interocean Canal Board godkände 1929 en tvåårig förstudie, senare kallad Sultan-rapporten efter upphovsmannen, den amerikanska arméingenjören. överste Daniel Sultan.