Blue Danube:
Felix Austria
By Mike Bennighof, Ph.D.
January 2022

Note: The Second Great War is our alternative history setting in which the First World War ended with a negotiated peace that allowed the great empires – Austria-Hungary, Germany, Russia and Ottoman Turkey – to survive for another generation’s war. Our Second Great War at Sea books tell the story and present new scenarios from this war that never happened waged by fleets that never were. River Battleships: Blue Danube is a unique crossover: a special Gold-Club-exclusive expansion for Panzer Grenadier: River Battleships that extends the Second Great War story line into the heart of southeastern Europe, and adds more river battles to Panzer Grenadier.

Austrian warships first patrolled the Danube River in the 16th century, and during the years that followed the Habsburg fleet maintained a powerful presence on the big river. The oar-powered gunboats and “river-frigates” assisted the land forces in the series of wars against the Turks, convoying supplies up and down the river and protecting river crossings.

After the 1848 Hungarian revolution had been crushed, the Danube flotilla seemed redundant and the force was dissolved in 1850. Most of its crewmen transferred to the growing blue-water Navy, while others transferred to the Army. Within a few years, this was seen to have been a serious mistake: the Austrians badly missed the power of a river flotilla to seal the Danube against potential Prussian crossings near Vienna in 1866, and the withdrawal of Belgrade’s Turkish garrison a year later opened another potential arena of conflict along the river.

The "Danube Frigate" Theresia, launched 1768.

In response, the newly-renamed Imperial and Royal Navy re-founded its Danube Flotilla, drawing personnel from the disbanded gunboat flotilla on Lake Garda and the blue-water fleet. The Navy’s chief constructor, Josef von Romako, designed a new steam-powered armored river warship drawing many concepts from American monitors, and the Austrians adopted the term as well. His design had an armored deck, an armored gun turret and a pair of high-revolution steam engines.

By 1914, the Danube Flotilla had eight armored monitors, and in the early morning hours of 29 July the flotilla fired the first shots of the Great War, bombarding the Serbian capital of Belgrade and in particular targeting Prime Minister Nikola Pasic’s office (Pasic, who had authorized the assassination of Archduke Franz Ferdinand, had already fled the city).

The flotilla performed well throughout the First Great War, and when peace came in December 1916 the flotilla had grown to 10 monitors, while two very large new monitors planned for construction in 1917 were cancelled instead. Wilson’s Peace mandated free navigation on the lower Danube where it formed an international boundary, and the river became a very busy commercial artery. Strings of heavily-laden barges head up or down the river almost hourly; as Serbs watch from the river’s south bank, their neighbors’ prosperity literally passes them by. When Serbia began building a powerful flotilla with Russian assistance, the Austrians scrapped their now-aged monitors to replace them with modern river warships of their own.

The last monitor designs of the Great War emphasized shore bombardment, with large guns and a copious store of ammunition. That required much greater size than previous monitors; the 1917 type would have displaced over 1,200 tons. The new-generation monitors are half that size at most, opting for better protection and naval guns. Their primary mission is to engage enemy monitors, something with which the flotilla did not have to be concerned in the First Great War.

The oldest boats (anything that navigates a river or lake is a “boat,” no matter what its size) in the Austrian river fleet are the monitors of the Dnistr class. They carry a single 150mm (5.9-inch) naval rifle mounted in a turret forward, and a 105mm gun in a turret aft. As with all the Austrian monitors, these are capable of high-elevation fire to allow them to engage in long-range artillery fire missions to support troops assure.

Built in the late 1920’s, they are no larger than the monitors built for the Great War, though they have better protection than the older generation and oil-fueled boilers adapted from those fitted in the blue-water fleet’s torpedo boats. They’re really intended to support Imperial and Royal troops along the riverbanks, but are well capable of fighting enemy monitors when needed.

The flotilla forms part of the Imperial and Royal Navy, though it often comes under Army command during wartime in a special bureaucratic relationship (something in which the Empire still specializes). As word came of Russian plans to build and supply modern monitors to the Serbs, the Navy commissioned a new design maximized for surface warfare,

Needing to keep the monitors’ draft reasonably shallow, the architects found it impossible to fit their designs with the armor protection they wished. The Hron class resembles a small coast-defense ship more than a traditional monitor, with a pair of 150mm guns mounted in single turrets fore and aft and a strong suite of 25mm anti-aircraft guns in open shielded mounts. Like the old monitors, their armament also has the elevation and optics for artillery missions. They carry as much protection as the designers could manage without creating a craft that drew too much water for the unpredictable depths of the Danube tributaries where the monitors might be called to serve.

Photographs and details of the big Zmaj-class monitors under construction by the Russians at Nikolayev for Serbia prompted an Austrian response. The Kupa class is an enlarged version of the preceding Hron class (all Austrian monitors are named for rivers of the monarchy, in keeping with tradition, though no longer solely for tributaries of the Danube). Kupa and her sisters are maximized for surface combat, with three 150mm guns mounted in a dual turret forward and a single turret aft. Like the earlier boats they have as much armor as can be fitted without excessively deepening their draft. And like the Hron class, they’re also fitted with special armored bays to transport Marines for assault landings. Marine detachments are also prepared to repel enemy boarders, or storm stranded enemy vessels.

Supplementing the big monitors are smaller patrol craft, used not only for patrols but for liaison duties, gunnery spotting and scouting in wartime and customs inspections during peace. The standard Austrian patrol boat is armored against small-arms fire and carries 25mm anti-aircraft guns fore and aft. Some are fitted for mine warfare, with equipment for laying or sweeping mines at the cost of reduced armament.

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Mike Bennighof is president of Avalanche Press and holds a doctorate in history from Emory University. A Fulbright Scholar and NASA Journalist in Space finalist, he has published an unknowable number of books, games and articles on historical subjects. He lives in Birmingham, Alabama with his wife, three children and his dog, Leopold.

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