Intended for the Ersatz Monarch (improved Tegetthoff) battleships, these guns were used as land artillery when those ships were cancelled.

The Austro-Hungarian Navy released the first specifications for these battleships on 3rd June 1911. The Marinetechnische Komitee or MTK (Naval Technical Committee) responded with two series of designs: A 22,000 mt (21,650 ton) warship armed with 30.5 cm (12") guns and a 23,400 mt (23,000 ton) ship with 34.5 cm (13.6") guns. Not satisfied with these, in February and March 1912 the Navy made a new series of displacement calculations with different armament and belt armor. Beside looking at the 34.5 cm (13.6") caliber, the Navy now also studied the possibility of introducing a 35.5 cm (14") caliber and asked Škoda to work on designs for turrets of this caliber with any-angle loading, similar in concept to contemporary British designs. Using their calculations as a basis, on 11th March 1912 the Navy released new specifications for a battleship armed with either 34.5 cm (13.6") or 35.5 cm (14") caliber guns. Based upon these specifications, Škoda on 1 April 1912 submitted drawings for 34.5 cm (13.6") twin and triple gun turrets to three shipyards and to the MTK, but their 35.5 cm (14") drawings were not yet finished at this time. These 34.5 cm (13.6") turrets were poorly protected and they had a complicated design, primarily due to their any-angle loading system which was more complex than those on British battleships. Utilizing these turret drawings, the shipyards and MTK then presented a total of 25 battleship designs back to the Navy. These designs ranged from 23,400 to 27,000 mt (23,000 to 26,600 tons) and were armed with eight to thirteen 34.5 cm (13.6") guns using the Škoda twin and triple turret designs.

On 25th June 1912 a board headed by Vice-Admiral Karl Kailer von Kaltenfels reviewed these designs and found them unsatisfactory. The board decided to instead pursue a new design for a battleship of about 24,500 mt (24,100 tons) armed with ten heavy guns. The board decided that these guns would be yet another new caliber, 35 cm (13.8"), and that they would have a simpler, fixed loading angle. The Navy placed an order with Škoda for guns of this caliber in July 1912 and asked Škoda to work out the designs for mounting them in twin and triple turrets.

The initial order to Škoda was for eleven guns; a prototype and then ten more guns to arm the first ship. The initial tests with the prototype, Rohr Nr. 1 (Barrel No 1), were performed at Pilsen on 20-21 November 1914. During these tests, the gun fired eight 1,400 lbs (635 kg) projectiles at muzzle velocities between 2,687 and 2,700 fps (819 to 823 mps). The test committee recommended reducing the muzzle velocity down to 2,625 fps (800 mps) in order to reduce wear and improve barrel life.

As the battleships would take years to construct, they were were cancelled soon after these tests but Škoda continued to build the guns which were now intended for use as Land artillery. These were slightly modified from the initial design and then designated as 35 cm L/45 M.16 (M.16 = Modell 1916). Including the prototype, a total of four of these guns were completed. The second gun was delivered to Trieste on 16 June 1916 and the third gun was delivered to Trieste on 31 December 1917. These three guns served mainly on the Italian front during the war. The fourth gun had not yet left the factory at the time of the Armistice and was later taken over by the French company Schneider-Creusot when they became the majority owners of the Škoda Pisen Works after the war. At this time, the remaining seven guns were in various stages of completion at the Pilsen works. None of these were finished and they were probably cut up for scrap a short time later.

The design of these guns was of built up construction and used a horizontal wedge breech. Actual bore size was 349.5 mm (13.76"). The data below is primarily for the Naval guns, see the Note below the Ammunition section for data on the Land guns.

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  Recoiling mass was 166,000 lbs. (75,300 kg).

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  Actual designations for Austro-Hungarian Projectiles

  APCBC	35 cm Panzergranate
  SAPCBC	35 cm Zündergranate
  CPCBC	35 cm Einheitsgranate

  
  These shells were sometimes called "bekappte Panzergranate" (AP shell with an AP Cap) and "bekappte Zündergranate" (SAP shell with an AP Cap).
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  Projectiles were all 5.25crh and all projectiles used both armor piercing and ballistic caps.
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  There were two proposed versions of the Zündergranate projectile. See photograph below.
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  The Einheitsgranate (AKA Einheitsgeschoß) was an APC design with a larger burster cavity, somewhat similar to a CPC type of projectile. The K.u.K. Kriegsmarine ultimately decided not to build this kind of projectile as it was something in-between an APC and a SAPC and and offered little advantage over those types.
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  Unlike previous Austro-Hungarian guns, this weapon split the propellant into a fore and rear section, similar to German large-caliber guns. It is noted that the propellant tubes for these charges were longer and thicker than those used for the 30.5 cm guns. As noted above, this charge weight produced new gun muzzle velocities of 2,687 to 2,700 fps (819 to 823 mps), so the charge weight would have been reduced slightly to meet the desired average gun MV of 2,625 fps (800 mps).
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  The rear cartridge had a 250 gm igniter.
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  The forward charge was in a thin brass casing about 0.5 mm (0.2") thick and which burned during firing. This had a 50 gm igniter at both ends.
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  The prototype gun used as land artillery fired 122 rounds before being returned to the factory. When examined it was reported that, despite minor chamber damages, the gun was still serviceable and "good for plenty more rounds". In the 1917 documents on 42 cm guns there is speculation on the causes of the shorter barrel life of the Škoda heavy guns compared to the Krupp ones. It was decided that the problem was the poor quality of the Austro-Hungarian propellant compared to the German RP C/12 propellant.
• ^

  12 practice rounds per gun were to be carried.
• When these Naval guns were converted to Land guns they were provided with a heavier shell, designated as 35 cm M.16 Granate, which was a Common type with a base fuze. This shell weighed 1,543 lbs. (700 kg) and used a propellant charge of 425.5 lbs. (193 kg) M/97f. This propellant type was more powerful and hotter burning than the newer M/97h which had been planned for the naval guns. The combination of heavier shell and stronger propellant gave a muzzle velocity of 2,525 fps. (770 mps) and a maximum range of 34,450 yards (31,500 m). See photographs and sketches below.

  A Note on Sources: "Naval Weapons of World War One" uses the above figures for this gun but does not mention that these were the values only for the Land guns and were not those for the Naval guns.

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  These turrets were to be fitted with a coupling device (Rohrkupplung) similar to the ones used on the Tegetthoff class which allowed the guns to be elevated as either coupled together or individually. It is believed that when they were coupled that their maximum elevation would have been +16 degrees.
• The turrets would have been all-electric operated, fed by 6×250 KW turbine-driven dynamos. On the evidence of the few existing drawings and documents, it seems that the ammunition supply would have been similar to the contemporary German turrets.
• Turret Armor Protection:

  Area	Twin Turret	Triple Turret
  Face, Vertical	340 mm KC	340 mm KC
  Face, Inclined	340 mm KC	340 mm KC
  Sides, Vertical	250 mm KC	300 mm KC
  Sides, Inclined	230 mm KC	230 mm KC
  Rear	300 mm KC	300 mm KC
  Roof	80 mm SP	80 mm SP

  KC = Krupp Cemented, SP = Speziatstahl - "Special Steel." This was also the material used for deck armor and torpedo bulkheads.

Kriegsarchiv, Vienna: MS/PK I-4/12 ex 191
Archive of the Hungarian Museum of Science, Technology and Transport, Budapest: Mladiáta-collection
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Original research by Mihály Krámli, author of "A Használhatatlan Lövegtornony Mítosza: Legenda Vagy Valóság?" [The Myth of the Useless Turret: Legend or Reality?] and "Az Osztrák-Magyar Monarchia Csatahajói: 1904-1914" [Austro-Hungarian Battleships and Battleship Designs: 1904-1914]
{Link - Hungarian to complete book in pdf form and Link - English}. Paperback copies printed on A4 paper and shipped from Hungary are available. Contact NavWeaps by clicking on the Contact link above or below.
Original research by Erwin F. Sieche

29 May 2004 - Benchmark
18 July 2010 - Updated with information supplied by Mihály Krámli
21 August 2010 - Added projectile pictures and information supplied by Mihály Krámli
07 April 2020 - Converted to HTML 5 format
17 July 2020 - Added mounting sketch and link to Mihály Krámli book
22 February 2024 - Added comment about the four completed guns
04 June 2025 - Reworked ammunition section, added data about Land guns
21 September 2025 - Added armor protection note
13 November 2025 - Added model photograph
13 January 2026 - Added drawings of Land gun ammunition