The Odensholm Action (August 26, 1914)

German Navy
26 August 1914


Mining the Gulf of Finland

Odensholm (currently Osmussaar, desolate island of 4.7 kilometers belonging to Estonia – where according to legend, Odin was burned at his funeral) was located 67 km southwest of Tallinn (59°17′30″N 23°23′30″E). By its strategic location, it closed the Gulf of Finland, gateway to the Baltic from St Petersburg. Upon declaration of war, it was entrusted to the care of the Hochseeflotte to lay mines at the entrance to the Gulf. On 25 August, were designated for this the cruisers Magdeburg and Augsburg. The first sailed from Königsberg (now Kaliningrad) and rallied the entrance to the Gulf during the night of August, 26.

SMS Magdeburg, German light cruiser

Return of fate

Unfortunately the weather was foggy, and the Magdeburg ran aground on shoals north of the island of Odensholm, at only 200 m from the lighthouse at midnight past 38 minutes, when the starboard forward hit sand where water was only 2.5 meters deep. Escorting destroyer V26 tried to take her in tow for digging out, but in vain. However, from the nearby island Lighthouse, as the weather cleared up in the first lights, the Russian watchman gave the alarm to the headquarters of the Baltic Fleet. The naval base of Tallinn was only 50 miles away. Situation was now critical and Lieutenant Commander Habenitch orders the crew to evacuate the ship and prepare for scuttling.

Russian cruiser Bogatyr


Charges were laid, confidential archives are burned in a boiler. As the crew prepares to embark on the V26, a watchman signaled two Russians cruisers in sight. This was actually the Bogatyr, followed at a distance by the Pallada, that came through at 9.10 am. The V26 resumed abruptly boarding operations and left the area immediately, leaving the men left to their fate. The cruiser had not brought the colors yet, so the Russians cruisers opened fire in a blind spot: The German cruiser would not even have time or opportunity to replicate. After warning shots, seeing that the German cruiser failed to comply and bring the colors down, they shelled the ship at short range and quickly blown its superstructures up. A raging fire started, and the beginning of a panic seized the German crew. Moreover, charges at the front blown up at the same time, the back charges then being inactivated probably to left time to evacuate the ship. As a result, the ship essentially was left unscaved, as the Russians quickly stopped firing and sent a boarding party.

Stranded SMS Magdeburg being evacuated (seen probably from a Russian cruiser’s bridge), as the front part has been blown up. The lighthouse can be seen 200m in the background. (Bundesarchiv)


Ultimately, 56 sailors and Commander Richard Habenicht were captured, 17 dead, 21 wounded and 85 missing were declared. Captain Nepenin, chief of intelligence of the Baltic fleet sent a search team who to find a copy of the precious codes book of the Hochseeflotte, the Signalbuch der Kaiserlichen Marine (SKM), which was eventually discovered under a pile of clothes in the room of the commander. This document was indeed of paramount importance, giving precious intelligence to the allies.

verlustliste-kleiner-kreuzer-magdeburg_2 - signal book of the Kriegsmarine Moreover two others were also found with their decoding manuals attached: The around maps (containing coded squares). Two of these copied code books were sent to the fleet of the Baltic and the Black Sea, and the third one sent to London by captains Kedrov and Smirnof that delivered these personally to Winston Churchill, then 1st Lord of the Admiralty. Discovered also were the 4977.73 Marks, maps with the registered German minefields and corresponding secret codes.

German signal flags.

These were immediately sent to the “Room 40” and intersected with other documents. From then on the Royal Navy and the Russian Navy will always have an edge over the Hochseeflotte. Indeed, the German staff ignored that the allies were now in possession of these ultra-secret documents, as the 56 men of the Magdeburg were held in Siberia until the capitulation. Moreover, in October 1914 the British also obtained the Imperial German Navy’s Handelsschiffsverkehrsbuch (HVB). This codebook was used by German naval warships, merchantmen, naval zeppelins and U-Boats. This case recalls another, which occur 19 years after: The seizing of enigma machines and breaking of the encryption code (which ultimately led to the invention of the computer).

Links & resources

Osmussar – Odensholm
German signal flags from 1815 (pdf)
The Code Bearers (Google book) By John Westwood
Das Ende von SMS Magdeburg
Room 40

Kaiserin und Königin Maria Theresia

Austria-Hungary (1893)

The first Austro-Hungarian Armoured Cruiser

The KuK Maria Theresia (abbreviated) was the first armoured cruiser of the Austro-Hungarians. Before, the only spent experience was on protected cruisers of Kaiser Franz Joseph I class. It goes without saying that the engineers were inspired largely by her. However, this cruiser integrated in its design British influences from several projects as Camell Laird, Fairfield, Napier, and the inevitable Vickers-Armstrong were contacted. But to save time, not yet named, the cruiser was started already on October 6, 1891 at STT Trieste.


Design Development

She was reset three times: In its original design, it was to comprise six 150 mm and fourteen 47 mm, but it was deemed too modest this endowment, especially since she had let him assume the role held by a battleship. Its launch was made April 28, 1893 and she was accepted into service in November 1894 with an armament of two 240 mm Krupp 35 calibers, eight 150 mm Krupp and 35 rapid-fire calibers, 12 Skoda 47 mm 44 calibers and 6 other Hotchkiss 33 calibers, 2 Skoda 66 mm howitzer (15 cal) to support the landings and four torpedo tubes that formed a diamond defense (sides, bow and stern).

The KuK Maria Theresia in service

The Kaiserin und Königin Maria Theresia was completely rebuilt in 1906 and 1910, loosing her thick poles, while the armament was reshuffle (see listing below), with all its 150 mm cannons being spread on the main deck. Its armor was not impressive, not exceeding 100 mm whereas the caliber of equivalent ships was far superior. Everything seemed sacrificed for weight gain, allowing to hold 19.35 knots, at the end a performance identical to the battleships she was supposed to evade in combat. She was criticized for its small dimensions.

In 1895 she participate in the celebrations for the opening of the Kiel Canal, stopping at brest and Portsmouth for courtesy visits in return. In 1897 she participated in the international fleet that demonstrated off Crete against the Greek annexation. She was deployed in 1898 to the Caribbean to safeguard Austro-Hungarian interests and evacuate Austrian and German nationals in the city of Santiago.


She was nearly shelled herself off Santiago de Cuba when crossing the Spanish fleet attempting to break the American blockade. She was also deployed in China in 1900, under Victor Ritter Bless von Sambuchi command and saw the end of the Boxer rebellion. In june 1901, she sailed up the Yangtze River, the biggest ship to ever do so. She then returned to Pola and was later rebuilt from 1908 to 1910.

Stationed in Sebenico (now Sibenik in Croatia) in 1914 she participated in shelling raids against Montenegro, then returned to port and until 1916 was used as coastguard. In January 1917 she was demobilized and taken to Pola to be moored as utility pontoon, its guns being unloaded and transferred to the Army. She was broken up soon after the war.


The KuK Maria Theresia class on wikipedia
On coll.
About Austro-Hungarian Cruisers
Specs Conway’s all the world fighting ships 1860-1905.

KuK Marian Theresia specifications

Dimensions 113,7 x 16,25 x 6,8 m
Displacement 5400 t standard – 6000 t FL
Crew 475
Propulsion 2 screws, 2 TE 3 cyl., 12 boilers, 9775 cv. 19,3 knots max
Speed 22 knots (40.7 km/h; 25.3 mph)
Range 7,000 nmi (12,960 km; 8,060 mi) at 14 knots (25.9 km/h; 16.1 mph)
Armament 2 x 190, 8 x 150, 14 x 47, 2 x 77 Howitzer, 4 x 37, 4 TT 445 mm SM (ft, rear, sides)
Armor Turrets 100, Casemate 80, Belt 100, Blockhaus 50, Bridges 57 mm


The KuK Maria Theresia freshly in service (1895)



In 1905 after the Boxer rebellion


Austro-Hungarian Submarines

Austria-Hungary (1909-1916)


Austro-Hungary has full awareness of its small size compared to its immediate neighbors and long declared enemy, Italy, and France beyond the peninsula. Submarines, just like torpedo boats were a way to recover cheaply some form of parity, although the naval staff left the impression to late to recognize the potential of submersible warfare. It’s only under a new impulsion in 1909 that it was voted the purchase of submarines in various naval yards, in the optic of a future local production. In 1909 indeed, three yards were chosen, Lake and Holland (USA) and Germaniawerft (Germany). Just like the German Navy, naval authorities preferred to wait for the pioneering work to be done and the technology gain in maturation.

U1 (Lake type, 1909)

The Naval Technical Committee (MTK) was ordered in 1904 to purchase a design, competition was open, and eventually three were retained, with two units for each. All three were relatively similar in size, displacement, but not so for technology and capabilities. The Lake type were the best divers but were disadvantaged for surface cruising, a bit like the Holland design, given a problematic gasoline engin that poisoned the crew. Germaniawerft design was by far the better for surface cruise, was roomy and reliable, the most solid with its double hull, but was the worst diver. This experience led the admiralty to define the ideal design, which ended with the first serie based on the German UD type. Because the war broke it it was only possible to ship smaller vessels by rail for assembly in Pola, so delays ensure they were not ready on time and Austria-Hungary entered the war with its tow prototypes series (The U1 serie was undergoing refitting of new engines).

The Havmanden-type Whitehead design from Denmark were the only commissioned serie in “numbers” (4) to see action, but the naval staff was not happy with it, and only see action for a short, late period, in the fall if 1917 due to reliability issues. For some time the captured ex-French Curie was the most capable and larger submarine in operation. Another solution was the fast assembly of small German UB types shipped by railed to Pola in prefabricated modules. The first contracts fall in February 1915, to AG Weser. They were intended for operations in the Dardanelles, which never took place. Licences were also negotiated for the construction of a serie of UBII types.

SM U31 assembled

The other important point is the presence and operation of German submarines. Although captain Hersing demonstrated his abilities to reach Pola with the U21, coastal types easy to assemble were preferred, shipped by rail. For security reasons, they all flew the Austro-Hungarian colours, despite a German crew and after a while, Austrian officers. In fact by October 1916 only the U35, 38 and 39 still flew the national flag. German flag was generalized. In March 1917 order for an “unrestricted sub warfare” was not seen as a good eye by Australian authorities as it also imply to sink hospital ships. At the end, communicates about ships sunk were collectively denominated “by the Central Powers”.


In total 27 Austrian submarines had been commissioned, and served with mixed results. 63 ocean-going types were planned but lack of workforce and of materials ensure massive delays and only a fraction ever saw operational service in time. For successes in combat, the ace was Georg Ritter Von Trapp (U5, U14) a future actor of a famous Hollywood movie, followed by another ace, Zdenko Houdecek (U17, 28), but the palm gone to the impressive U27 that include one destroyer and 35 civilian ships (mostly schooners).



Globally Austrian subs sunk Armoured Cruisers Leon Gambetta and Giuseppe Garibaldi, destroyers Phoenix, Renaudin, Fourche, Impetuoso, Nembo, submarins Circe and Nereide and badly damaged the Jean Bart, Dublin, Weymouth, even the Japanese destroyer Sakaki and 108 civilian ships had been sank or captured, plus 11 more unconfirmed.

These German U-boats (about 70 of them) operated from Pola and Cattaro.The Gäa was their default depot and supply ship. They were joined at some point with locally assembled Torpedo Bootes, A51 and A82. They operated from Pola. German crews usually tend to despise their Austro-Hungarian fellow sailors, because of a supposed relaxed discipline in order to release tensions between a multitude of ethnicities, whereas German crews were a disciplined and homogeneous lot.


Some submarine projects never materialized, like the experimental Loligo, intended to be used on Lake Garda. Another was a cruiser cargo submarine influenced by German Deutschland and intended to reach neutral Spain. It was a proposition by the naval league, but rejected because naval yards were already busy with more urgent ships to deliver. It was dropped in August 1916. Another design was submitted in the Autumn of 1916, a river model able to operate along the Serbian and Bulgarian shores of the Danube. But the over-ambitious asks it was intended for eventually condemned the project as unfeasible.


Links/sources – The Austro-Hungarian Submarine Force by Erwin Sieche
Central Powers subs on
U1 class on Wikipedia
The SM U3 on Wikipedia
The U5 class on Wikipedia
The SM U6 on Wikipedia
The SM U10 on Wikipedia
The SM U12 on Wikipedia
The SM U23 on Wikipedia
The SM U30 on Wikipedia
About Ritter Von Trapp
Specs Conway’s all the world fighting ships 1906-1921.

U1 class (2, 1909)


First submersible of the Austro-Hungarian navy, U1 and U2 were from plans drew by the American engineer Thomas Lake. Their original gasoline engines were under-powerful and were quickly replaced. Dumping procedures were particularly arduous, to the point they needed 8 minutes for diving. Therefore, they never saw action, being relegated to training tasks in Pola until January 1918, date of radiation from service. They were ceded to Italy in 1920, who hastened to them demolished.

Displacement & Dimensions :220-277 tons surf/dive, 30.8 x 4.8 x 3,90m
Propulsion: 2 diesel engines, two propellers, 200/720 hp. and 6/10.3 n. max.
Crew: 17
Armament: 1 removable 37mm cannon, 3 TT 450mm (two bow, a stern).

U3 class (2, 1909)

U3 and U4 in Pola

While the former Austro-Hungarian submarines were of American origin, Lake patent, the next two were ordered in Germany at Germaniawerft and allowed to test the latest technological advance of this country. The U3 and U4, issued in 1908 had a double hull and internal ballasts. Testing showed excessive design problems and had to be partly refitted and rebuilt. Despite of this they were unsatisfactory but unlike previous submersibles, widely used during the war: The U3 was sunk by French destroyer Bisson after a failed attack of Città di Catania, and after being rammed and forced to surface in August 1915. U4 sank the cruiser Giuseppe Garibaldi on July 18, 1915 and many other ships. It was ceded to France in 1919 and demolished in 1920.

Displacement & Dimensions:  240-300 tons surf/dive, 42.3 x 4.5 x 3.8 m
Propulsion: 2 electric and 2 gasoline engines, 2 propellers, 600/320 hp. and 12/8.5 n. max.
Crew: 21
Armament: 2 TT 450mm (bow torpedo 3).

U5 class (3, 1909)


After trying Germaniawerft and Lake the Austro-Hungarian Admiralty turned to Holland for the delivery of its next submarines. She ordered two units, and a third optional. Whitehead installed in Fiume produced these Holland licensed designs. Industrial assembly was such that basic modules were prepared in the USA, then shipped to Fiume, but this caused structural problems. U5 and U6 were launched in 1909, and U7 (later U12) was finally launched in 1911. The latter was offered for sale to the Austrians who refused after their disappointments with the U5 and U6, but eventually bought it while she was still unsold in August 1914. Torpedo tubes were mobile and had opening hatches cloverleafs. U5 hit a mine in 1917 but was salvaged and repaired. It was fitted with a German kiosk and new 75 mm gun. The U6 tried to penetrate the barrage of Otranto and was caught in a net, here crew evacuated as she was scuttled. U12 hit a mine while trying to force Venice entry in August 1916.

Displacement & Dimensions: 240-273 tons surf/dive, 32.1 x 4.2 x 3.9 m
Propulsion: 2 electric motors, two gasoline engines, 2 propellers, 500/230 hp. and 10.7/6 n. max.
Crew: 19
Armament: 2 TT 450mm (bow torpedo 4).

U10 class (5, 1915)


U-7 to U11 with has been too large to be built in sections and shipped to Pola by rail, so they never reached the Adriatic back it November 1914. They were sold to Germany instead and joined the Hochseeflotte. For cons, AG Weser shipyards proposed to build UB1 class subs in removable sections, because of their reduced tonnage they were though to be transported by rail more easily to Pola, and assembled on site. Five units were therefore commissioned in April 1915. At first the U10 and U11 entered service in June-July 1915, with a German crew and an Austrian officer. The U15, 16 and 17 followed in December 1915, this time with a fully Austro-Hungarian crew. All received 37 mm and later 47 mm gun in November 1917, while the U11 received a 66 mm. U16 torpedoed in October 1916 the destroyer Nembo, but was rammed by the freighter Borminda and had to be scuttled. U10 hit a mine in July 1918, was recovered and towed to Trieste, but never repaired. The others had an uneventful carrer and were given to Italy as war reparations, which in turn decided to have them demolished in 1920.

Displacement & Dimensions: 140 125 tonnes surf/dive, 27, 9x 5.2 x 2.7 m
Propulsion One diesel, one electric motor, 1 propeller, 260/120 hp. and 6.5/5.5 n. max.
Crew: 17
Armament: 2 TT 450mm (bow torpedo 4).

U14 (1912)


One of the best Austro-Hungarian submersible was U14, which “double life” is quite an interesting one: It was indeed at the origin the French submersible Curie (Brumaire class, a Laubeuf type sub, in 1912). The Curie was sent in the Adriatic in 1914 to monitor fleet safe passage and guard merchant traffic. But she also tried to enter Pola to torpedo the best units in the fleet. On 20 December 1914, she almost reached its goal but was found stuffed into a net and could not disengage. She was later discovered, and shelled to destruction. Then she was refloated in January 1915, sent to Pola to be repaired, and modified. Among others, she added a new Germanic kiosk type, a 88 mm gun and two Germans diesels. She was accepted into service in 1916 after testing in November, and placed under the command of Georg Ritter von Trapp. U14 was assigned to France as war reparations after the war and served until 1928 under its former name.

Displacement & Dimensions: 263-300 tons surf./dive 36.1 x 4.4 x 3.7 m
Propulsion: 2 propellers, 2 Diesels, 2 electric motors, 284/280 hp. and 9.2/5.8 n. max.
Crew: 22
Armament: 2 TT 500 mm (bow torpedo 4) 1 88 mm gun, 1 8 mm Schwartzlöse MG.

U20 class (4-1916)


Four submarines were produced Whitehead of Fiume in 1915 on plans originally designed for a Danish order, that of Havmanden in 1912. Their design was therefore inspired by the Holland license, but their construction time was considerable, due to the allocation of construction in many subcontractors Austrians and Hungarians. The U20 and 21 to Pola, U22 and 23 to UBAG. They were operational in October-November 1917 and their active campaign was short and without success. The U23 was sunk in a dirgigeant attque in the passage of Otranto against an Italian convoy in February 1918, the U20 was torpedoed by the Italian submarine F12 before the estuary of the Tagliamento in July 1918, and the other two ceded to Italy and France and promptly demolished.

Displacement & Dimensions: 173-210 tons surf./plongée 38.8 x 4 x 2.8 m
Propulsion: 1 Propeller, one diesel, one electric motor, 450/160 hp. 12/9 and kn. max.
Crew: 18
Armament: 2 TT 450 mm (bow torpedo 4), 1x 66 mm gun, 1x 8 mm MG.

U27 class (8-1916)


The most prolific serie by far and the best of the Austro-Hungarian navy was that of U27, designed on the basis of type Ubii under German license. The order was given to Pola on October 12, 1915 and no less than 8 units were started, including two at Danubius, Fiume. They were launched from 1916 to 1917 and operational in 1917, the U41 being lengthened by 77 cm to accommodate the diesel of U6, damaged in combat but recovered. They formed in a short time an excellent hunting score, U27 alone claiming a destroyer and 33 freighters, U28 (commanded by Maj. Zdenko Houdecek) a destroyer and 11 freighters. U30 was sunk in the Strait of Otranto in 1917, and the others were allocated postwar Italy and demolished in Fiume and Venice.

Displacement & Dimensions: 264-300 tons surf./dive 36.9 x 4.4 x 3.7 m
Propulsion: 2 propellers, 2 Diesels, 2 electric motors, 270/280 hp. and 9/7.5 kn. max.
Crew: 23
Armament: 2 TT 450 mm (bow torpedo 4) 1x 75 mm gun, 1x 8 mm MG.

U43 class (2-1917)


The last two Austro-Hungarian submarines to enter service were the U43 and U47, Type Ubii Weser built in 1916 and conveyed by rail to Pola, assembled on site, and entering service under German flag and crew. They were sold June 21, 1917 in the Austro-Hungarian navy, but not long in service. After the armistice, they were offered as war reparations to France but scrapped in situ in 1920.

Displacement & Dimensions: 263-300 tons surf./dive 36.1 x4.4 x3.7 m
Propulsion: 2 propellers, 2 Diesel, 2 electric engines, 284/280 hp. and 9.2/5.8 kn. max.
Crew: 22
Armament; 2 TT 500 mm (bow torpedo 4) 1x 88 mm gun, 1x 8 mm MG.


The Antivari Action (August 14 1914)

Austro-Hungarian Navy
14 August 1914

Antivari A visual of the area and route taken by the Allied ships. Although this engagement was all but fair (a recent dreadnought against an old cruiser) the ultimate result was almost a year round of inactivity for the Austro-Hungarian Navy (K.u.K Kriegsmarine) in the Adriatic

The Austro-Hungarians at war

The war broke out because of the Balkans, the assassination of Archduke Franz-Ferdinand was followed by a rejected inquiry by Austro-Hungarian authorities to Serbia, followed by a rejected ultimatum and war. By the alliances game, Serbia had the support of its natural ally Russia, which in turn could count on France. In response, Austria-Hungary was able to count on the German Empire for backup. But the first engagements of the Austro-Hungarian Army against Serbia, despite clear advantages, was nothing of a promenade. The Serbs managed to block and even repel the initial attacks with massive payback.

Situation in the Adriatic

On the naval front however it was expected from the K.u.K Kriegsmarine to take advantage of a clear cut superiority in the Adriatic. At that stage, the Austro-Hungarian Navy was not to be taken lightly with three brand new dreadnoughts (a fourth in achievement), 12 pre-dreadnought battleships, 13 cruisers, 27 destroyers and 79 torpedo-boats, as well as 7 submarines and many monitors and auxiliary ships of all sizes and tonnage. It was based mostly in Pola harbour and could easily defeat a very weak Montenegrin navy (perhaps a single gunboat, no info could be found) whereas the Serbian “navy” only counted a single patrol boat Jadar, based on the Danube in 1915. Since Italy was neutral, and perhaps then more inclined to join the central powers, Austro-Hungary has free hands in this “private lake” bordering the Balkans. In the Mediterranean however, this was another matter.

Austro-Hungarian Dreadnoughts and the fleet anchored at Pola
Austro-Hungarian Dreadnoughts and the fleet anchored at Pola. Despite real assets, from 1915, it was dwarfed by the combined might of the French, British and Italian navies and mostly condemned to inaction, trapped in the Adriatic.

At that time, since June 6, the proportion of the French fleet in the Mediterranean was such that the British thought fair to let the supreme naval command in the area to the French, the British naturally receiving supreme command of the Allied naval forces for the north sea. Thus, by treaty on June 6, the Royal Navy there was reduced to two armored cruisers (Defence and Warrior) and some light cruisers after by massive transfers to the North Sea,theoretically under the orders of Admiral Boué Lapeyrière. The latter, from the outset of the declaration of war, rallied Malta with the combined forces, then joined the Adriatic by executing an ostensible “naval review” in full strength and regalia to impress still undecided Italians.

The battle

On August, 14 the French fleet enters the Adriatic included 15 battleships (2 Courbet, 6 Danton and 5 Vérité), 6 armored cruisers (3 Léon Gambetta, Quinet, Renan, Michelet) and smaller cruisers. It was followed by British-armored cruisers from Gibraltar, the squadron of Admiral Troubridge. Alerted, the Austro-Hungarian fleet scrambled to rally in emergency the safe harbor of Pola. But Zenta had not been informed, and was still conducting operations of shelling of the small Antivari harbour.

She was safeguarded by destroyer Uhlan and 2 others. None did noticed the Courbet, a recently built dreadnought which opened fired at 20 000 m range. Soon 305 mm plumes squared the Zenta, which had no artillery capable of replicate at such distance. In very little time, the Zenta was severely hit, immobilized, and rendered all but helpless and burning. Her crew evacuated the soon-to-be hulk on rafts. The Destroyer Uhlan and two destroyers managed to flee thanks to their speed. The Zenta sank in a short time, but most of its crew safely joined the coast.

SMS Zenta and Ulan in august 14 Antivari battle
A painting of the battle of Antivari, by Harry Heusser, 1914.


This modest setback meant that the allies could now roam at will the Adriatic, blocking all the Austro-Hungarian initiatives. Initially at least, French presence dissuaded the naval forces stationed at Pola to start new coastal raids. But soon the allied forces departed and would be fully absorbed by operations in the Dardanelles. The Austro-Hungarian was then again free and ready for any action but only for a short time: Italy entered the war at about the same time. We will return on this chapter of the adriatic naval campaign soon. The “inaction” ended with a first major action Battle in Decemlber 1915, the battle of Durazzo, followed by by the Battle of the Strait of Otranto in 14-15 may 1917.

Austro-Hungarian Fleet
The Austro-Hungarian fleet

The cruiser Zenta in 1914.