Is the Danube river navigable?
21209639#10
The Danube flows through many cities, including four national capitals (shown below in bold), more than any other river in the world. Ordered from the source to the mouth they are:
The Danube is navigable by ocean ships from the Black Sea to Brăila in Romania and by river ships to Kelheim, Bavaria, Germany; smaller craft can navigate further upstream to Ulm, Württemberg, Germany. About 60 of its tributaries are also navigable.
Danube
297809#115
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.
Socialist Federal Republic of Yugoslavia
21209639#42
Apart from a couple of secondary navigable branches, the only major navigable rivers linked to the Danube are the Drava, Sava and Tisa. In Serbia, a canal network also connects to the river; the network, known as the Danube–Tisa–Danube Canals, links sections downstream.
Danube
34375#14
There are 1,716 kilometers of navigable inland waterways (1,043 km of navigable rivers and 673 km of navigable canals), which are almost all located in northern third of the country. The most important inland waterway is the Danube (part of Pan-European Corridor VII). Other navigable rivers include Sava, Tisza, Begej and Timiş River, all of which connect Serbia with Northern and Western Europe through the Rhine–Main–Danube Canal and North Sea route, to Eastern Europe via the Tisza, Begej and Danube Black Sea routes, and to Southern Europe via the Sava river. The largest river port is Novi Sad (1.18 million tons of cargo tonnage in 2016), while other river ports include Belgrade, Smederevo, Pančevo, Prahovo, Apatin, Bačka Palanka (all on Danube), Šabac (on Sava), and Senta (on Tisza).
Transport in Serbia
23612531#2
Postwar discussion of the Danube River was begun by the United States in 1945 when President Truman proposed at the Potsdam Conference that freedom of navigation should be assured on Europe's inland waterways. Britain and France were concerned with reestablishing their prewar positions as members of the European Commission of the Danube.
In 1947, the Paris peace treaties signed with Romania, Hungary, and Bulgaria guaranteed free navigation.The foreign ministers of Britain, France, the USSR, and the United States stipulated that:
Navigation on the Danube shall be free and open for the nationals, vessels of commerce and goods of all states, on a footing of equality in regard to port and navigation charges and conditions for merchant shipping. The foregoing shall not apply to traffic between ports of the same state.
Danube River Conference of 1948
25637#16
The Danube is by far Romania's most important river, not only for transportation, but also for the production of hydroelectric power. One of Europe's largest hydroelectric stations is located at the Iron Gates, where the Danube surges through the Carpathian gorges. The Danube is an important water route for domestic shipping, as well as international trade. It is navigable for river vessels along its entire Romanian course and for seagoing ships as far as the port of Brăila. An obvious problem with the use of the Danube for inland transportation is its remoteness from most of the major industrial centers. Moreover, marshy banks and perennial flooding impede navigation in some areas.
Geography of Romania
12484222#9
The Danube is by far Romania's most important river, not only for transportation, but also for the production of hydroelectric power. One of Europe's largest hydroelectric stations is located at the Iron Gates, where the Danube surges through the Carpathian gorges. The Danube is an important water route for domestic shipping, as well as international trade. It is navigable for river vessels along its entire Romanian course and for seagoing ships as far as the port of Brăila. An obvious problem with the use of the Danube for inland transportation is its remoteness from most of the major industrial centres. Moreover, marshy banks and perennial flooding impede navigation in some areas.
Topography of Romania
34287810#0
EAEMDR was established as an organization in 1935 under the name “Danube Hydrographical Service” within the structure of the Ministry of Railways. The headquarters were situated in the city of Lom and the responsibilities of the Service were related to the maintenance of the waterway, creation of maps of the Danube River, conduction of hydro meteorological surveys in the Bulgarian section of the river. In 1949, after the ratification of the “Convention for the sailing regime on the Danube River”, the Danube Hydrographical Service passed over to the Ministry of Defense – Danube Fleet. Four years later the service was reinstated as a part of the Ministry of Transport, information technology and communications and the Navigational Waterway Office was established in Ruse. In the year 1955 the organization passed over under the structure of the Bulgarian River Fleet and in the next year the Council of Ministers adopted a decree, by the force of which the Navigational Waterway Office was restructured into the “Administration for the Maintenance of the Navigational Waterway and Exploration of the Danube River” within the Ministry of Transport, Information technology and communications. 
In December 1999 the Administration was transformed into the Executive Agency for Exploration and Maintenance of the Danube River.
Executive Agency for Exploration and Maintenance of the Danube River
19745#4
The Main is navigable for shipping from its mouth at the Rhine close to Mainz for to Bamberg. Since 1992, the Main has been connected to the Danube via the Rhine-Main-Danube Canal and the highly regulated Altmühl river. The Main has been canalized with 34 large locks () to allow CEMT class V vessels () to navigate the total length of the river. The 16 locks in the adjacent Rhine-Main-Danube Canal and the Danube itself are of the same dimensions.
Main (river)
587845#29
The Sava is navigable to larger vessels for between its confluence with the Danube in Belgrade, Serbia and Galdovo Bridge in Sisak, Croatia, upstream from confluence of Sava and Kupa rivers. The confluence marks the westernmost point of the river course designated as a Class IV international waterway in compliance with the United Nations Economic Commission for Europe's European Agreement on Main Inland Waterways of International Importance (AGN). The classification means that the river course between Sisak and Belgrade is navigable to ships of the maximum length of , the maximum beam of , the maximum draught of and tonnage up to . The Sava River downstream of Sisak, is designated as European waterway E 80-12, branching off from the E 80 waterway spanning the Danube and Le Havre via the Rhine. The largest ports on the Sava River are Brčko and Šamac in Bosnia-Herzegovina, Sisak and Slavonski Brod in Croatia, and Šabac and Sremska Mitrovica in Serbia.
Sava