Socialist Federal Republic of Yugoslavia
Regarding rivers, the Danube was navigable throughout its entire course in Yugoslavia, linking the ports of Belgrade, Novi Sad, and Vukovar with Central Europe and the Black sea. Long stretches of rivers Sava, Drava and Tisza were also navigable.
Commissions of the Danube River
In 1938, a committee of experts inspected the Sulina and found it was almost impassable by that time. And in August of that same year, the regime of the two commissions was swept away by rise of German power on the river. A series of treaties put control in the hands of the Germans, who maintained it until the Nazi retreat in 1944 and ultimate defeat in 1945. In 1948 a Danube river conference was held, and a new treaty was adopted, putting governance of the river under commissions composed only of the riparian powers, ending more than four decades of Western European presence in the control of the important waterway.