Naval History Homepage and Site Search


World War 1 at Sea

Kaiserlich und Koniglich or k.u.k Kriegsmarine

by Gordon Smith, Naval-History.Net

Dreadnought Viribus Unitis (Photo Ships, click to enlarge)  


Naval War in Outline
Austrian ship titles
Warship numbers & losses, 1914-18
Losses by year
Key to main characteristics including Austrian torpedo and gun calibres
Main ship types - Dreadnoughts to Submarines




Apart from one major fleet sortie on the declaration of war between Austria and Italy on the 23rd May 1915, and an aborted one in June 1918 when dreadnought 'Szent Istvan' was lost, the Austrian heavy ships spent the entire war as a fleet-in-being within the Adriatic Sea, holding down a large portion of the Italian and French battle fleets as well as units of the Royal Navy. Most of the action in the Adriatic that took place involved the well-handled destroyers, submarines and to a lesser extent light cruisers of the Austrian Navy.

The initially small Austrian submarine force was unable to play a role outside the Adriatic, and by early 1915 the Germans were sending U-boats into the Mediterranean, in part to attack the Allied fleet off the Dardanelles. As Italy had declared war on Austro-Hungary but not Germany, the German boats operated under the Austrian ensign and were temporarily commissioned into the Austrian Navy. Once Germany and Italy had gone to war in August 1916, German U-boats operated under their own flag. Although the Austrian submarine fleet did not grow to large numbers it had an impressive record - damaging French dreadnought 'Jean Bart', and sinking:

Armoured cruisers - French 'Leon Gambetta', Italian 'Giuseppe Garibaldi'

Destroyers - British 'Phoenix', French 'Fourche' and 'Renaudin', Italian 'Impetuoso' and 'Nembo'

Submarines - French 'Circe', Italian 'Nereide'


Key to Austrian titles


Erzherzog - Archduke; Kaiser - Emperor; Kaiserin - Empress; Konigen - Queen; Kronprinz - Crown prince; Sankt - Saint




August 1914 Strength

Wartime additions

1914-18 losses













Pre-dreadnought battleships




Coast defence ships




Armoured cruisers




Protected cruisers




Light/scout cruisers




Aircraft and seaplane carriers

















LOSSES BY YEAR - (In date order within each year)

Year - Ships lost (all in Adriatic Sea, except 'Kaiserin Elisabeth' in Far East)
1914 - protected cruiser 'Kaiserin Elisabeth', light/scout cruiser 'Zenta'
1915 - submarines 'U.12', 'U.3', destroyers 'Lika', 'Triglav'
1916 - submarines 'U.6', 'U.16'
1917 - submarine 'U.30', destroyer 'Wildfang', coast defence ship 'Wien'
1918 - submarine 'U.23', destroyer 'Streiter', submarines 'U.20', 'U.10', dreadnoughts 'Szent Istvan', 'Viribus Unitis'

Key to Main Characteristics


Tonnage - standard displacement; Speed - designed speed at standard displacement, rarely attained in service; Main armament - sometimes changed as the war progressed; secondary armament usually changed; Complement - normal peace time. Exceeded in war with consequent reduction in living space and higher battle casualties; Year - year or years class completed and normally entered service. Only includes ships completed up to war's end; Loss Positions - estimated from location unless available from reliable sources; Casualties - totals of men lost, or survivors plus saved, will often exceed peacetime complements.


Austrian torpedo and gun calibres in inches:

Torpedoes: 53.3cm - 21in; 50cm - 19.7in; 45cm - 17.7in

Guns: 30.5cm - 12in; 24cm - 9.4in; 19cm - 7.5in; 15cm - 5.9in; 12cm - 4.7in; 10cm - 3.9in; 8.8cm - 3.5in; 7.5cm - 2.9in; 6.6cm - 2.6in



August 1914 Strength (3)

1. TEGETTHOFF class, PRINZ EUGEN, TEGETTHOFF, VIRIBUS UNITIS, class of four, 1 lost, 1 completed in 1915) - 20,000t, 20 knots, 12-30.5cm/12-15cm/20-6.6cm, 1912-14

SMS Viribus Unitis, believed firing a forward turret (Photo Ships)

In August 1914, the three completed 'Tegetthof' dreadnoughts and three 'Radetzky' pre-Dreadnoughts formed the First Battle Squadron, spending most of the war as a fleet-in-being

VIRIBUS UNITIS ('with joined forces'), 1st November 1918, northern Adriatic Sea at Pola (Pula) naval base (c 44-45’N, 13-45’E) - Italian 'Mignata' (or leech) self-propelled mines. With the fall of the Austro-Hungarian Empire, the state of Yugoslavia was formed by the southern Slavs and declared on the side of the Allies. 'Viribus Unitis' (Capt Janko Vukovic de Podkapelski, also provisional Yugoslav Fleet commander) was taken over on the 31st October by the Yugoslav National Council as flagship of the new navy. Apparently ignoring the new political situation, the Italians went ahead with a planned attack on Pola. Early in the morning of the 1st November and with few defensive precautions now being taken, two Italian frogmen, Maj of Naval Engineers Raffaele Rossetti and Doctor Lt Raffaele Paolucci, slipped into the naval base and attached mines to the dreadnought and liner 'Wien'. Both ships sank, 'Viribus Unitis' capsizing and going down around dawn. Several hundred men died including the new Captain.

Wartime Additions (1)

1. Last of Tegetthof class, SZENT ISTVAN, lost - as above

SZENT ISTVAN (King Stephen 1 of Hungary), 10th June 1918, northern Adriatic Sea, south east of Pola (Pula), nine miles southwest of Premuda island (c 44-15’N, 14-30’E) - 2 torpedoes from Italian motor boat 'Mas.15'. Leaving Pola on the 9th, she and the three other 'Tegetthof' dreadnoughts of the 1st Battle Division, First Battle Squadron sailed to support a planned cruiser raid on the Otranto Barrage, now believed by the Germans to be a serious obstacle to U-boat movements. Two Italian anti-submarine motor boats - 'Mas.15' and 'Mas.21', both 16 tons and armed with two-45cm torpedoes, happened to be out in the northern Adriatic, towed there for a minesweeping mission. 'Mas.15' (Cdr Luigi Rizzo, who sank the coast defence ship 'Wien' in December 1917 - below) hit the 'Szent Istvan' amidships at 03.30hrs on the 10th. She rolled over and sank at 06.00hrs with 89 men lost. 'Mas.21' missed the 'Tegetthoff', but both Italian boats escaped and the Austrian operation against the Otranto Barrage was called off.

(latest researchs shows the possibility that 'Szent Istvan' was hit by 3 torpedoes - twice by MAS 15 and once by MAS 21. Due to the conditions - twilight etc, MAS 21 probably attacked her and not 'Tegetthof' as noted above. The information has not been confirmed offically. More can be found at the bottom of  and Information is again courtesy of Danijel Zavratnik from Slovenia)  



August 1914 Strength (3)

2. RADETZKY class, ERZHERZOG FRANZ FERDINAND, RADETZKY, ZRINYI, 3 ships - 14,500t, 20 knots, 4-30.5cm/8-24cm/20-10cm, 890 crew, 1910/11

SMS Radetsky (Photo Ships)

In August 1914, the three 'Radetzky’s' and three completed 'Tegetthof' dreadnoughts formed the First Battle Squadron

All three ships, serving as the 2nd Battle Division, First Battle Squadron, took part in a May 1915 shore bombardment of the Italian coast with the three dreadnoughts, but thereafter remained inactive at Pola as a fleet-in-being



August 1914 Strength (6)

3. HABSBURG class, ARPAD, BABENBERG, HABSBURG, 3 ships - 8,230t, 18 knots, 3-24cm/12-15cm, 625 crew, launched 1900-02

In August 1914, all six pre-dreadnoughts formed the Second Battle Squadron. The three 'Habsburg’s' served as the 4th Battle Division, but were later decommissioned as harbour guardships

4. ERZHERZOG KARL class, ERZHERZOG FERDINAND MAX, ERZHERZOG FRIEDRICH, ERZHERZOG KARL, 3 ships - 10,500t, 19 knots, 4-24cm/12-19cm, 750 crew, launched 1903-05

In August 1914, the three 'Erzherzog Karl’s' formed the 3rd Battle Division of the Second Battle Squadron



August 1914 Strength (4)

5. KRONPRINZ ERZHERZOG RUDOLF, KRONPRINZ ERZHERZOG RUDOLF, Local defence ship, Cattaro (Kotor) Bay - 6,830t, 16 knots, 3 old 30.5cm/6-12cm, 455 crew, launched 1887

6. MONARCH class, BUDAPEST, MONARCH, WIEN, 3 ships, 1 lost - 5,500t, 17 knots, 4-24cm/6-15cm, 435 crew, 1897

All three ships formed the 5th Battle Division, but remained in reserve

WIEN (Vienna), 10th December 1917, northern Adriatic Sea, off Muggia in the Bay of Trieste (c 45-30’N, 13-45’E) - torpedoed by Italian motor boat 'Mas.9'. Based with the 'Budapest' at Trieste and used in support of the Austrian army fighting on the Italian front, the two old ships were preparing to carry out a shore bombardment. Two of the 16 ton, 2-45cm torpedo-armed motor boats, 'Mas.9' and 'Mas.13' were towed from Venice by torpedo boats 9PN and 11PN to within 10 miles of Trieste. Cutting through the heavy hawsers that protected the anchorage the two craft broke through and launched their torpedoes. 'Mas.9' (Lt Luigi Rizzo - see the 'Szent Istvan' above) hit the 'Wien' which went down rapidly, but 'Mas.13' missed 'Budapest'. They both returned safely to Venice. Most of 'Wien’s' crew was saved



August 1914 Strength (3)


These ships formed the 1st Cruiser Division, but Kaiserin und Konigen Maria Theresia spent 1914-16 as harbour guardship, Sebenico (Sibenik) and from 1917 as German U-boat accommodation ship, Pola



August 1914 Strength (3)

8. KAISER FRANZ JOSEPH I class, KAISER FRANZ JOSEPH I, KAISERIN ELISABETH, 2 ships, 1 lost - 4,000t, 6-15cm, 1892

Kaiser Franz Joseph I soon decommissioned as harbour defence ship

KAISERIN ELISABETH, 2nd November 1914, Chinese waters, off Tsingtao (Qingdao) in Kiaochow Bay (c 36-00’N, 120-15’E) - blown up and scuttled. Represented the Austrian Navy on the Far East Station at Tsingtao. Most of her guns and guns crews were landed as the 'Elisabeth' Battery for the defence of the German naval base during the Japanese siege. The largely disarmed old cruiser was scuttled five days before the final surrender on the 7th November



August 1914 Strength (4)

9. ZENTA class, ASPERN, SZIGETVAR, ZENTA, 3 ships, 1 lost, survivors served from 1918 as accommodation or target ships - 2,300t, 8-12cm, 300 crew, 1899

ZENTA (Austrian-Ottoman Battle of Zenta), 16th August 1914, southern Adriatic Sea, off Antivari (Bar), Montenegro (c 42-00’N, 18-30’E) - French heavy gunfire. 'Zenta' (Cdr Paul Pachner) and escorting destroyer 'Ulan' were blockading the Montenegran coast in foggy conditions when surprised by the main French battlefleet under Adm Lapeyrere, now based at Malta with the aim of keeping the Austrian fleet locked in the Adriatic. 'Ulan' escaped to the north, but 'Zenta' was cut off and received at least two heavy shell hits from dreadnought 'Courbet'. Severely damaged, she blew up and sank around ten minutes later, but most of her crew of 300 reportedly got ashore in their boats

10. ADMIRAL SPAUN - 3,500t, 27 knots, 7-10cm, 330 crew, 1910

Wartime Additions (3)

11. Modified ADMIRAL SPAUN class, HELGOLAND, NOVARA, SAIDA, 3 ships - 3,500t, 27 knots, 9-10cm, 340 crew, 1914-15

Helgoland took part in the December 1915 raid into the Adriatic to interfere with the Allied evacuation of Serbian forces

All three cruisers took part in the May 1917 attack on the British drifters patrolling the Otranto net barrage



August 1914 Strength (25)

12. METEOR - 430t, launched 1887

13. BLITZ class, BLITZ, KOMET, MAGNET, PLANET, SATELIT, TRABANT, 6 ships - 380-605t, launched 1888-1896

14. HUSZAR class, CSIKOS, DINARA, HUSZAR, PANDUR, REKA, SCHARFSHUTZE, STREITER, TURUL, ULAN, USKOKE, VELEBIT, WILDFANG, 12 ships, 2 lost - 390t, 28 knots, 6-6.6cm/2-45cm tt, c 70 crew, launched 1906-10

STREITER (Fighter), 16th April 1918, northern Adriatic Sea off Laurana in the Quarnero channel (now The Kvarner, Croatia) (c 45-00’N, 14-15’E) - collision with SS 'Petka'. 'Streiter' escorting convoy including the 'Petka'

WILDFANG (Tomboy), 4th June 1917, northern Adriatic Sea, west of Peneda Island, Brioni Islands (Brijuni) off Pola (Pula) naval base - mined. Believed based at Cattaro (Kotor) at the time. On reconnaissance patrol when sunk by a floating mine

15. TATRA class, BALATON, CZEPEL, LIKA, ORJEN, TATRA, TRIGLAV, 6 ships, 2 lost - 850t, 32 knots, 2-10cm/6-6.6cm/2-45cm tt, 105 crew, launched 1912-13

LIKA (region in Croatia) , 29th December 1915, southern Adriatic Sea, off Durazzo (Durres), Albania (c 41-15’N, 19-15’E) - Italian mines. Two Italian destroyers were reported carrying troops to Durazzo at the time of the Serbian evacuation in the face of the slowly advancing Austrian army. An Austrian force of scout 'Helgoland' and five 'Tatra' destroyers were ordered to search for the Italians, and if unsuccessful destroy any shipping in Durazzo. After sinking the French submarine 'Monge' on passage south. the destroyers entered the harbour at daybreak, sank three small ships and as shore batteries opened up, turned into a minefield. 'Triglav' and 'Lika' detonated mines, 'Lika' sinking at once; survivors were picked up by her sister ships

TRIGLAV (mountain in Slovenia), 29th December 1915, southern Adriatic Sea, off Cape Rodini, Albania (c 41-30’N, 19-00’E) - scuttled after striking Italian mine off Durazzo. On the same mission as 'Lika', 'Triglav' was badly damaged in the same minefield. 'Czepel' attempted to take her in tow, but fouled a propeller, and the job was taken over by 'Tatra'. As the crippled Austrian force returned slowly north at 6 knots, Allied ships got between them and their Cattarro base. 'Triglav' was abandoned, but attempts to scuttle her failed. She was finished off by five French destroyers of the 'Casque' group, including 'Casque' herself

Wartime Addition (5)

16. WARASDINER - 390t, 30 knots, 6-6.6m/4-45cm tt, 75 crew, launched 1912

17. Ersatz (equivalent) TATRA class, DUKLA, LIKA (2), TRIGLAV (2), UZSOK, 4 ships - 880t, 32 knots, 2-10cm/6-6.6cm/4-45cm tt, 115 crew, launched 1917



August 1914 Strength (5)

18. U.1 class, U.1-U.2, 2 boats - 230/250t, 10/6 knots, 3-45cm tt, 17 crew, launched 1909

19. U.3 class, U.3-U.4, 2 boats, 1 lost - 240/300t, 12/8 knots, 2-45cm tt, 21 crew, launched 1909

U.3, 13th August 1915, Southern Adriatic Sea, NE of Brindisi (41-00’N, 18-15’E) - gunfire of French destroyer 'Bisson'. Italian AMC 'Citta di Catania' patrolling the northern end of the Strait of Otranto was attacked by the German-built 'U.3' (Lt Cdr Karl Strnad) on the 12th, but not hit. 'U.3' is believed to have been rammed and badly damaged in return, and was unable to submerge. Allied destroyers were called up and next morning on the 13th she was sighted on the surface and sunk by 'Bisson's' gunfire; 7 men were lost including Lt Strnad, and 14 survivors picked up

U.4 torpedoed and sank Italian armoured cruiser 'Giuseppe Garibaldi' in the central Adriatic in July 1915

20. U.5 class, U.5-U.6, class of 3 boats, 2 completed before war, 1 lost - 240/275t, 8/6 knots, 2-45cm tt, 19 crew, 1910/11

U.5 torpedoed and sank French armoured cruiser 'Leon Gambetta' in the southern Adriatic in April 1915

U.6, 13th May 1916, Southern Adriatic Sea in Strait of Otranto, 12m ENE of Cape Otranto (40-10’N, c 18-45’E) - British drifter nets and gunfire. Attempting to break through the Otranto Barrage at night, 'U.6' (Lt Cdr Hugo von Falkenhausen) fouled the nets of patrolling fishing drifter 'Calistoga', surfaced and was shelled by her and the 'Dulcie Doris' and 'Evening Star II'. The Austrian boat was scuttled and all 15 crew saved. One source gives the date as the 10th May. Throughout the war, only two U-boats were confirmed sunk in the Otranto Barrage - Austrian 'U.6' at this time and German 'UB.53' in August 1918

21. U.7 class, U.7-U.11, under construction in Germany and sold to the German Navy in November 1914. Commissioned as German U.66-70

Wartime Additions (21)

20. (above - concluded) U.5 class completed 1914 with 'U-12'

U.12 torpedoed and damaged French dreadnought 'Jean Bart' in the Adriatic Sea in December 1914

U.12, 8th August 1915, northern Adriatic Sea, off Venice, NE Italy - Italian mines. Most sources presume she was lost on mines on or around the 11th or 12th trying to penetrate the harbour defences of Venice. Kemp's 'U-Boats Destroyed' is more specific - 'U.12' (Lt Cdr Egon Lerch) was on patrol off Venice and on the 6th August damaged by Italian destroyer 'Rossolina Pilo'. Two days later an explosion was observed in a defensive minefield and divers sent down. The wreck of 'U.12' with her stern damaged was found 7.6 miles bearing 104 degrees from the Punta Sabbioni lighthouse in the Venetian lagoon; all 13 crew were lost with her

22. U.10 class coastal boats, U.10-U.11, U.15-U.17, 5 boats, 2 lost - 125/140t, 6/5 knots, 2-45cm tt, 17 crew, launched 1915.

Transported from Germany to Pola in sections, 'U.10' initially commissioned as German 'UB.1', 'U.22' as 'UB.15'

U.10 (ex-German 'UB.1'), damaged 9th July 1918, northern Adriatic Sea, off Caorle, NE Italy in the Gulf of Venice (c 45-30’N, 13-00’E) - Italian mines. Heavily damaged by a mine, 'U.10' (Lt Cdr Johann von Ulmansky) was beached between Caorle and the estuary of the Tagliamento River. She was salvaged and towed to Trieste, but not repaired before the end of the war; all her crew of 13 were saved

U.16, 17th October 1916, southern Adriatic Sea, off Valona (Vlore), Albania (c 40-45’N, 19-00’E) - Italian convoy ships and escorts. During a convoy attack, 'U.16' (Lt Cdr Oerst von Zopa) torpedoed Italian destroyer 'Nembo', but was then sunk herself. She may have been rammed and badly damaged by one of the convoyed ships, Italian steamer 'Borminda' (or 'Bermida'), and scuttled. Or otherwise sunk by the exploding depth charges of 'Nembo' which had not been set to 'safe' before she went down; 11 of 'U.16’s' crew including her CO were lost and two survivors picked up

23. U.14 - 400/550t, 12/9, 1-53.3cm tt/6-53.3cm external torpedoes/rearmed with 1-8.8cm, 28 crew, recommissioned 1915.

Ex-French 'Curie', sunk off Pola in December 1914, raised and repaired

24. U.20 class coastal boats, U.20-23, 4 boats, 2 lost - 175/210t, 12/9 knots, 2-45cm tt/1-6.6cm, 18 crew, launched 1916/17

U.20, 4th July 1918, northern Adriatic Sea, off the estuary of the Tagliamento River, west of Trieste (45-29’N, 13-02’E) - torpedoed once by Italian submarine 'F.12'. The attack on 'U.20' (Lt Cdr Ludwig Muller) by the surfaced 'F.12' took place on the night of the 4th/5th from a range of 650 yards. Other sources give the date as the 6th or 9th July 1918; all her crew were lost. 'U.20’s' salvaged midships section and conning tower is on display at the Heeresgeschichtliches Museum, Vienna

U.23, 21st February 1918, southern Adriatic Sea, off Valona (Vlore), Albania in the Strait of Otranto (40-26’N, 19-02’E) - Italian torpedo boat 'Airone'. 'U.23' (Lt Cdr Klemens von Bezard) was first sighted on the surface by 'Airone' which attempted to ram. Once submerged the destroyer sunk her with a towed explosive paravane. Sources differ on 'U.23’s' activities at this time - she was either attacking an Allied convoy or attempting to break through the Strait of Otranto, or perhaps both; all her crew were lost

25. U.27 class coastal boats, U.27-U.32, U.40-U.41, 8 boats, 1 lost - 265/300t, 9/7 knots, 2-45cm tt/1-7.5cm gun, 23 crew, launched 1916/17, built at Pola to German 'UB-II' design

U.30, early April 1917, possibly southern Adriatic Sea in the Strait of Otranto area - missing. 'U.30' (Lt Cdr Friedrich Fahndrich) sailed from Cattaro (Kotor) on the 31st March 1917 for Mediterranean patrol between Malta and Crete, and was never seen again. Some sources suggest she disappeared around the 1st or 2nd, cause unknown, but possibly mined in the Otranto Barrage or an accident off Cape Otranto. She might also have gone down in the Mediterranean, one of the few U-boats lost in the area in 1917; all her crew were lost

26. U.43 class coastal boats, U.43, U.47, 2 boats - 265/290t, 9/6 knots, 2-50cm tt/1-8.8cm gun, 22 crew, 1917.

Originally German 'UB.43' and 'UB.47' from 1916, but sold to Austrian Navy and recommissioned in July 1917



Note - My thanks to Danijel Zavratnik from Slovenia for noting that most of the place names are Italian spellings and that many have changed since World War 1.

The old Italian names and the modern Croatian, Montenegran and Albanian equivalents are as follows:

Brioni = Brijuni
Laurana = Lovran
Pola = Pula
Quarnero = Kvarner
Sebenico = Sibenik

Antivari = Bar
Cattaro = Kotor

Durazzo = Durres
Valona =Vlore



see also


French Navy

Royal Hellenic or Greek Navy

Imperial Japanese Navy

Turkish or Ottoman Navy

United States Navy


return to Naval-History.Net

revised 3/8/11


if any ads offend, please contact Naval-History.Net