ship, there were four /40 caliber guns in two twin turrets on the centerline. These guns were an Austro-Hungarian replica of the 24 cm/40 (9.4") Krupp C/94, which was used on the Habsburgs. The guns could be depressed to −5° and elevated to 30°. The arc of fire of the guns was 300°, or 150° in each direction. Each gun required a crew of twenty men. At maximum elevation, the gun could fire a shell . They could fire three to four armor-piercing shells per minute at a muzzle velocity of . Each of the guns weighed at least . Their secondary armament consisted of twelve /42 caliber guns, also made by Škoda, mounted in eight single casemates on either wing of the ship and two single midships turrets on the either wing of the ship. They could be depressed to −3° and elevated to 20°. They could fire a armor-piercing shell at maximum elevation with a muzzle velocity of . The gun weighed 12.1 tons and could fire three rounds per minute. The ships had a tertiary armament for protection against torpedo boats in the form of the /45 caliber gun, too manufactured by Škoda. They could be depressed to −10° and elevated to 20, and had an arc of fire of 360°, meaning that they could fire at any target within their range of fire. The guns could fire about ten to fifteen rounds per minute. At their maximum elevation, the guns could fire a high-explosive charge at a muzzle velocity of . Anti-aircraft and airship protection was covered by the four Vickers anti-aircraft guns on the ship. They could be depressed to −5° and elevated to 80°. They had an arc of fire of 360°, which meant that they also could engage any target within their range. Manually operated by only one crewman, they could fire a shell at maximum elevation with a muzzle velocity of . Designed in 1910, each of the guns weighed . After 1916-17 refits two Škoda 7 cm L/45 guns on anti-aircraft mounts were installed. The Erzherzog Karl class was also fitted with two above water torpedo tubes, although they were rarely used. Armor The armor plating of the battleships around the waterline belt, one of the more vulnerable areas of a ship, was , while their deck armor was . The turrets and casemates had and armor respectively. This was done