Kaiser Max-class ironclad (1862)

Following the launch of the French Gloire, the world's first ironclad warship, the Austrian Navy began a major ironclad construction program under the direction of Archduke Ferdinand Max, the Marinekommandant (naval commander) and brother of Kaiser Franz Josef I, the emperor of Austria.^[1][2] The first two ships, the Drache class, were ordered rather hastily in response to the construction of two similar vessels for the Royal Sardinian Navy in 1860, sparking the Austro-Italian ironclad arms race. The Kingdom of Sardinia soon unified most of Italy early the following year, and the expanded Italian Regia Marina (Royal Navy) became Austria's principal naval threat. But to secure funding for further expansion of the Austrian fleet to counter the growing strength of the Regia Marina, Ferdinand Max needed to convince the Reichsrat (Imperial Council) to authorize funds for more ships.^[3]

In early 1861, Ferdinand Max promulgated a memorandum laying out his construction proposal. In it, he argued that the advent of ironclad warships, which had rendered wooden ships obsolescent, had cleared the slate for the world's naval powers. By building a fleet of nine ironclads, Austria could achieve a fleet that was a third the size of the French Navy, then the second-largest fleet in the world. It would be more than capable of defeating the Regia Marina (under its known construction plans), and it would make Austria an attractive ally to Britain, France's traditional rival. For the 1862 fiscal year, Ferdinand Max requested funding for three new ironclads, and to convert the sail frigates SMS Novara and SMS Schwarzenberg to screw frigates. The Reichsrat rejected funding the proposal later in 1861, but in October, Franz Joseph intervened and authorized the navy to place orders for the new ships, which became the Kaiser Max class.^[4] These ships were designed by the Director of Naval Construction Josef von Romako; he based the design for the three new ships on the Drache class, but enlarged it and incorporated more powerful engines. The new ships also carried more guns.^[5]

The Kaiser Max-class ships were 70.78 meters (232 ft 3 in) long between perpendiculars; they had a beam of 10 m (32 ft 10 in) and an average draft of 6.32 m (20 ft 9 in). They displaced 3,588 long tons (3,646 t). Wooden hulled vessels, they proved to be very wet forward and had to have their bows rebuilt in 1867. Each ship originally had a bow figurehead, which was removed during the reconstruction. They were also very unstable ships, pitching badly and having very bad seakeeping. The ships had a crew of 386.^[6]

Their propulsion system consisted of one single-expansion, 2-cylinder, horizontal steam engine that drove a single screw propeller. The number and type of their coal-fired boilers have not survived, though they were trunked into a single funnel located amidships. The engines were rated 11 knots (20 km/h; 13 mph) from 1,900 indicated horsepower (1,400 kW); on trials, Kaiser Max slightly exceeded those figures, reaching 11.4 knots (21.1 km/h; 13.1 mph) from 1,926 ihp (1,436 kW).^[6] Don Juan d'Austria was capable of only 9 knots (17 km/h; 10 mph).^[7] They were fitted with a three-masted rig to supplement the steam engines.^[6]

The ships of the Kaiser Max class were broadside ironclads. Kaiser Max and Prinz Eugen were armed with a main battery of sixteen 48-pounder muzzle-loading guns, while Don Juan d'Austria received fourteen of the guns. The ships also carried fifteen 24-pounder 15 cm (5.9 in) rifled muzzle-loading guns manufactured by Wahrendorff. They also carried two smaller guns, one 12-pounder and one 6-pounder. In 1867, the ships were rearmed with a battery of twelve 7 in (178 mm) muzzle-loaders manufactured by Armstrong and two 3 in (76 mm) guns. The ships' hulls were sheathed with wrought iron armor that was 110 mm (4.3 in) thick.^[6][7]