Monitors of the Danube Flotilla, 1870-1918

Map of the Danube

Maros - 1871    |    Körös - 1893    |    Temes - 1904    |    Enns - 1914    |    Links

The mighty Danube, 1,771 miles long (2,850 km) from its alpine source to its mouths at the Black Sea, is the second longest river in Europe and one of its most heavily traveled. Before railroads, before roads, it was the great thoroughfare of commerce in Eastern Europe, flowing through the heartlands of Austria and Hungary and the lands to the east, forming national borders, fostering the growth of towns. The great river had formed a defensible frontier since Roman times, and had been well-used by the Habsburgs from their early struggles against the Turks in the 1500s through the Napoleonic Wars. With the advent of Metternich's balance-of-power diplomacy after Waterloo, peace seemed assured. So the Danube defenses were neglected, to the sorrow of the Habsburg realm when Otto von Bismarck came a-knockin' in 1866 at the head of a Prussian army. After the Austrian defeat at Königgrätz, the invasion route lay open unopposed as far as Vienna, forcing Austria to sue for peace -- a peace that was consummated on July 21, 1866, the day after Austria's naval victory at Lissa; a peace that cost Austria her leadership position in the German Confederation and smoothed the way for Prussia's takeover of Germany. On the heels of the Königgrätz catastrophe, Vienna's military minds set out to rethink the imperial defenses. One expedient promptly adopted was the building of a floatilla of river ironclads. The Danube Patrol was born.

The Maros Class

SMS MAROS - pen-and-ink sketch

SMS Maros (seen above in a drawing by Aldo Cherini) was one of the original pair of monitors that founded the Danube monitor flotilla in 1871.

SMS LEITHA - pen-and-ink sketch

The Maros and Leitha of 1871 were the inaugural pair of Danube monitors. Designed by Josef von Romako (the navy's chief naval architect, and brother to the celebrated painter and Navy booster), these two ironclads were state-of-the-art for their day. They were steel vessels of some 425 tons, propelled by twin screw, and powered by vertical high-speed steam engines -- an innovation at the time. Higher revolutions permitted the use of smaller screws, essential in these shallow-draft river craft. The ships mounted two 6" muzzle-loading rifles (MLR) in an armored turret on the foredeck. Beginning a tradition, the ships were named for tributaries of the Danube. The monitors operated as the heavy guns of the flotilla, which included steam picket boats, tenders, and despatch carriers.

Above and at right, Leitha as rebuilt in the early 1890s. Rig was cut down; ships were re-engined and equipped with new 4.7" BLRs to match the new ships just added to the fleet. Leitha pioneeered the armored deck in the K.u.K. Kriegsmarine, with a 1" thick (25.4 mm) Bessemer steel surface added to her weather deck. Spark arrestor on funnel functions as similar contrivances did on western railroads in the U.S. (diamond and balloon stacks), preventing blowing cinders from causing fires along the riverbanks.

The Körös Class

SMS KOROS on the river: pink back lightTwenty years after the Maros class's debut, state of the art had shifted, as reflected in new construction. Körös and Szamos, commissioned 1893-4, were designed by Josef Thiel. The design was an update and improvement on the Maros class, with nickel-steel armor, 4.7"/35 cal Skoda rifles, and triple-expansion engines. Seen here at day's end on the Danube, the Körös shows the outward essentials: two beam turrets with one gun in each, cylindrical conning tower between and somewhat aft of the turrets; wireless antenna strung from bow to a midships mast. Just visible at the stern is an additional field piece, a 4.7" howitzer which could be fired at higher elevation than the turret guns. This class saw extensive action during World War I. In fact Körös went into action against Serbia within hours after war was declared in August 1914. On Aug. 4 she took 6 direct hits while flushing out a concealed Serb battery; in late September, in combination with Temes (below) and the minesweeper Andor, the Austrian vessels broke through a Serbian minefield and invaded the Save River. Leitha was mauled by shore artillery, having one of her turrets disabled and all its crew killed, and all her guns put out of action. She was sent to the Slavonic-Mitroviça yard for repairs and took no further part in combat.

The Temes Class

SMS TEMES at anchor: pen-and-ink drawing

Beginning in the 1890s, it was agreed to build a new pair of monitors every 10 years. The 1903/04 pair was Temes and Bodrog, built at the Danubius yard in Budapest. As can be appreciated from the excellent illustration above by Aldo Cherini, they employed a twin turret mounting updated 4.7" rifles. Temes struck a mine and sank in the Save River as part of the same operation described just above the picture, on October 23, 1914. The ship was salvaged and repaired, re-entering service in 1917. At bottom, the ship in later life as the Romanian monitor Mihail Kogalniceanu; in this guise she survived WWII to be scrapped in the 1950s.

The Enns Class

SMS ENNS, backlit shot w/smoke

Ten years later, the Enns (shown) and her sister Inn were built at a branch of STT in Linz, Austria, upriver from Vienna, commissioning in 1914. These 526-ton ships appear to be repeats of the Temes class in terms of design. An additional pair of monitors constructed at Linz for the K.u.K. Kriegsmarine were named Sava and Bosna, commissioned 1915. Yet another pair of monitors was laid down under the wartime budget of 1916. Assigned again to STT/Linz, these would have marked at significant increase in size and power at 1,270 tons and 7.5" armament; but they were never completed and their hulls were scrapped shortly after the War.

The Enns joined the other monitors in a hellish bombardment of Belgrade preceding the final assault on the Serb capital, which capitulated October 8, 1915. Before their surrender the Serbs returned the compliment with their artillery, their hits starting leaks on Enns, Bodrog, and Temes -- leaks so severe the vessels had to be evacuated after nightfall. After some time in the yard, the Danube fleet was in action again during the 1916-17 war against Romania, further downriver. Inn hit a mine and sank in October 1916 in an incident which claimed the life of her captain, Korvettenkapitän von Förster. The ship was salvaged the following month, but repairs were never completed owing to wartime shortages of materials.

In the final year of the War, following armistices with Russia and Romania, the entire surviving Danube flotilla journeyed to the river's mouth in the Black Sea and visited Ukrainian and Romanian ports -- rather a turn-about from the bellicose tone Austria had adopted in the last days of Franz Josef, leading directly to the calamity of WWI. The ships tied up at Budapest on Nov. 20, 1918 and paid off their crews, who departed into the baffling new Europe of toppled dynasties and jostling successor states. The ships of the Danube flotilla were doled out to the victors by an international commission whose reasoning was every bit as bewildering as the new map of Europe.

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