The Austro-Hungarian Submarine Force

by Erwin Sieche (

The following has been excerpted from "Austro-Hungarian Warships In Photographs, Vol. 2. 1896-1918" by Baumgartner & Sieche, translation courtesy of Erwin Sieche.

The A.­H. Navy, like the Imperial German Navy, had a negative opinion of submarines originally. Since tenders did not lead to useable domestic designs, the decision was taken in 1906, to procure three proven submarine types from abroad and to subject them to tests, expecting that this would permit a more precise definition of the Navy's requirements. This position led to the procurement of two units each of Lake­, Germania­, and Holland­boats.

The 100­feet single­hull boats U 1 and U 2, based on plans prepared by the American engineer Simon Lake, were built at the Naval Arsenal Pola between June 1907 and April 1909. Special features of the Lake boats were diver locks and retractable wheels fixed to the keel. It was expected that the wheels would permit the boats to roll along the sea bottom. Because of the diving tanks being part of the deck superstructure, diving time amounted to eight minutes­the time required to fill them up. During the following years the boats were subjected to elaborate trials, showing that they performed excellently when sailing submerged. Originally the boats were equipped with gasoline engines ­leased from the Lake Corporation­ for surface cruising. Due to the high risk ­fire and poisoning fumes­ of these engines, they were replaced by Diesel engines of domestic production in 1915.

The slightly bigger double­hull boats U 3 and U 4 were built by the Krupp Germania shipyard at Kiel (work numbers 135 and 136) between spring 1907 and November 1908, and then towed to Pola. Their sea­going properties and on­board space was better than those of their competitors, but Germania had huge problems with depth steering. The stern diving rudders were converted several times.

The single­hull boats U 5 and U 6 corresponded with the type designed by the American engineer John Philip Holland, the US Submarine Octopus. The boats were pre­produced at the Electric Boat Company yard in New York, and the parts reassembled under a license agreement by Whitehead & Co., Fiume (now Rijeka). Because of their distinctive "teardrop­shape" the boats had excellent underwater cruising abilities.

Whitehead & Co. built ­at their own risk­ an improved Holland­boat, the S.S.3, by incorporating all experience and lessons learned from the first two boats. However, the A.­H. Navy showed no interest, because it had decided to acquire sea­going bigger boats in the meantime. In addition available funds were exhausted. The shipyard offered to boat later to numerous navies but without any success.

Whitehead & Co. built three single­hull boats Havmanden (Waterman), Thetis, and 2. April for Denmark in 1911/12. They were further developments of the Holland­type boats for which licenses had been obtained from the Electric Boat Company. The boats met expectations and the Danish navy classified the submarine­type as Havmanden A­class Following the original designs four more units Nymfen, Najaden, and Havfruen. were built at the State Shipyard Copenhagen under the supervision of Whitehead engineers. Austro­Hungarian submarine officers naturally inspected the boats while under construction at Fiume (Rijeka) and were impressed by the good use of available space and the shipyard's accurate workmanship.

After concluding comparative trials the A.­H. Navy laid down its requirements for future submarines: 500­t displacement, 18 knots speed above surface and 12 knots below, two to three bow torpedo tubes, two side or stern tubes. Bids were received from the Whitehead shipyard, offering their Type K­I, developed as "colonial submarine" for the Dutch Government. The Germania Shipyard, Kiel offered ­as a project­ further development of the U 3/U 4 type. Stabilimento Tecnico Triestino (STT) submitted a very general proposal since they had no previous experience in submarine construction.

Finally it was decided to accept Type 506d of the Germania Shipyard. Supporting this decision was the experience of the Germans, the reliability of the Germania­boats, and the "fighting price" which was 8% below those offered by the competitors. Five boats were ordered from Kiel on February 1, 1913 and laid down between November 1, 1913 and February 11, 1913 under work numbers 203­207. Construction paid attention to Austrian industrial suppliers and recognized special A.­H. Navy demands and incorporated Austro-Hungarian developments in the design. The boats were launched on April 22, May 15, June 1, June 24, and July 20, 1915; but at this stage they were already sold to the Imperial German Navy. Austria­Hungary thought soon after the outbreak of the war, that it would not be feasible to transfer the boats through enemy controlled waters into the Adriatic; over­land transport was impossible due to the boats' size. Consequently the five boats were officially sold to Germany on November 28, 1914. They were commissioned as German U 66 to U 70. Rumors that the boats were confiscated by Germany are false. Soon after the sale it was discovered, belatedly, that the transaction had been premature, because the German submarine U 21 (Hersing) arrived at the Bocche di Cattaro ­sailing from Wilhelmshaven­ on May 13, 1915. It had traveled the long and dangerous journey without enemy interference and demonstrated that submarines of this size could well venture into the Mediterranean.

At the beginning of the war the A.­H. submarine arm had at its disposal six, only conditionally useable trial boats and immediate action for a rapid build­up was called for. As a first step, the S.S.3, not yet sold, was bought and commissioned as U 12. Due to time pressure the Navy had to fall back on available and tried constructions.

Negotiations with the Imperial Navy Department in Berlin for submitting plans and parts of the UB­I type dragged on at the beginning. Since funds were available due to the sale of U 7 to U 11, the Navy decided to build submarines of the Havmanden­type, for which blueprints existed as well as some materials which had been stockpiled for planned follow­on boats. However, many parts of this type were protected by patents and license agreements, in addition the neutral USA was not permitted to supply war materials to any belligerent country. A solution was found by establishing a new corporation, the Hungarian Submarine Construction joint­stock Company (UBAG­Ungarische Unterseebootsbau A.G.) with headquarters in Fiume and a branch office at Linz/Austria. Staff was seconded from Whitehead, in a manner that the new firm was working under the supervision and warranty of Whitehead. To the outside world it was a wholly independent enterprise under the influence of the Navy. Subsequently the Navy confiscated the construction plans in accordance with existing war emergency laws, and planned to construct ten boats of this type. Since these boats were coastal submarines and the Navy Command preferred an ocean­going type, only four Havmanden boats were ordered. Delivery date was set at 15 months.

Due to the Monarchy's dual state nature, an embarrassing and bitter political quarrel ­in the middle of the war!­ ensued about placing the orders, which ended only after a compromise was reached: the submarines should be built by Stabilimento Tecnico in part at their shipyard at Linz, in part by the Naval Arsenal Pola. Assembly should take place, according to the prevailing situation, either with Ganz & Co. ­ Danubius, Fiume or Pola. The result was that the order was split into two lots of two boats each, with different appearance and equipment. Due to increasing shortages of materials, lack of skilled labor, and acts of sabotage, construction delays occurred and the boats were ready for service only at the end of 1917 and saw little action.

An unexpected windfall came through the capture of the French submarine Curie. The French navy was the only one that accorded tactical importance to submarine warfare and had developed a sizeable submarine fleet. When war broke out France disposed of 79 submarines ready for action. It did not take long before the first appeared in the Adriatic. One of them was the Curie of the Brumaire­class, built by the Toulon Naval Shipyard and launched on July 18, 1912. The Brumaire­class was the Diesel version of the Pluviôse, designed by the French engineer Maxim Laubeuf. She was towed by the French armored cruiser Jules Michelet up the mid­Adriatic and went into a waiting position off the Navy's main base Pola. When the Curie tried to sneak into the harbor on December 12, 1914, she got helplessly entangled in the submarine net barrage and had to surface 5 hours later to disembark its crew. The intruder was fired upon by the destroyer Magnet and the torpedo boat Tb 63 T and sank at the entrance of the harbor. Three crew members were killed but 23 survived. In remembrance of the boat's Second Officer a French submarine of the inter­war period was named Pierre Chailley; another one, the O'Byrne, was named after the captain who died in France in 1917 after having been released from Austro­Hungarian captivity.

The wreck was salvaged in steps from a depth of 39 m in the time from December 21, 1914 till February 2, 1915. The boat was only slightly damaged and due to the demand for big submarines the boat was repaired and commissioned as U 14 on June 6, 1915.

The extended negotiations with Germany had finally come to an end by March 1915 and resulted in an order of five submarines of the UB I type. This type was well known to the A.­H. Navy since the Imperial German Navy had transported its UB 3, UB 8, and UB 9 by rail to Pola and reassembled them there. From Pola they started operating against the Allied forces at the Dardanelles.

The first boat was bought by the A.­H. Navy on April 4, 1915, a 'sample' UB I boat, with construction having been started already on November 1, 1914 at the Germania Kiel shipyard. Disassembled into three sections and transported by rail to Pola for reassembling, it was commissioned on June 4, 1915 ­because of difficult handling temporarily with a German crew­ as A.­H. U 10 under Oberleutnant zur See Wäger. The second boat, UB 15, was bought from the AG Weser and commissioned as U 11, with a German crew under the command of Oberleutnant zur See von Heimburg at Pola on June 4, 1915. The boat sank the Italian submarine Medusa off Venice on June 6, 1915. An Austro­Hungarian crew took over on June 18, 1916.

Three UB I boats U 15 to U 17 ordered by the A.­H.Navy and built by the AG Weser, Bremen (work numbers 232­234) were commissioned together on October 6, 1915. In the Monarchy these boats were nicknamed 'Okarina' (an Italian musical instrument) because of their shape. Due to their small size they were not appreciated by crews, although they surpassed all previous A.­H. submarines in their reliability.

Cantiere Navale Triestino purchased ­as a next step­ the license for the construction of the German UB II type from AG Weser, Bremen, which was, however, modified according to requirements by the A.­H. submarine arm. Since the CNT Monfalcone shipyard had been conquered by the Italian army, Cantiere had to work as 'sub­tenant' at the Naval Arsenal Pola where U 27, U 28, U 40, and U 41 were built. Ganz & Co. ­ Danubius built U 29 to U 32 at its shipyards at Budapest and Fiume. Once more had the Hungarian part of the Monarchy succeeded in obtaining ­in contravention to the quota regulations­ 50 percent of the order despite the fact that necessary construction installations were not available.

Both shipyards exceeded the delivery dates. Main reason was not the admittedly poorly equipped shipyards but the unreliability of outside suppliers. The boats were commissioned in stages from January 1917 on, the last being U 41. The latter being the replacement for the lost U 6 and the last sub built by an Austro­Hungarian shipyard and still commissioned during the war. Since two U 6 replacement Diesels were still available, the hull had to be lengthened by one frame to accommodate them. All UB II boats saw action during the war.

As early as November 1, 1916, the German Korvettenkapitaen (Cdr.) Arno Spindler inquired privately, in a discussion with the A.­H. Navy Attaché in Berlin, if Austria­Hungary might be interested to take over German submarines, because Germany was encountering bottlenecks in finding trained submarine crews. Following extended official negotiations ­the critical point was the out­flow of gold reserves to Germany­ agreement was reached on the purchase of two UB II submarines which, after extended service, were in poor shape. The presented nevertheless a welcome addition to the A.­H. submarine force.

U 43 ex­German UB 43 and U 47 ex German UB 47 were commissioned by the Imperial German Navy on April 24, and July 4, 1916 respectively. Both had operated in the Mediterranean, were decommissioned on June 21, 1917 and taken over by the A.­H.Navy which commissioned both boats on July 7 of the same year.

Construction of several ocean­going submarines was started during the war but none was completed.

As a consequence of Italy entering the war on May 23, 1915, the strategic framework of the A.­H. submarine­arm was fundamentally changed. Ocean­going submarines were urgently needed. The Naval Technical Committee prepared specifications for an ocean­going submarine in August 1915: a speed of 17 knots above and 10 knots below surface, range 4,000 miles, 3­4 torpedo tubes, one 7.5 cm gun. It was ironic: half a year earlier the similar submarines U 7 to U 11 were sold to Germany.

All domestic shipyards were invited to submit bids. But they were confronted with immense problems in building ships. The Cantiere Navale Triestino (CNT) at Monfalcone was founded by the Österreichische Schiffahrts AG and the koda Werke AG, both owned by the Credit-Anstalt für Handel und Gewerbe which was backed in part by Rothschild capital. Following Italy's declaration of war, the CNT shipyard at Monfalcone had to be evacuated, because its proximity to the Italian border. The shipyard was occupied by the Italians on June 8, 1915 and was under heavy artillery fire by the Austrians during the 2. Isonzo battle from July till September 1915. CNT relocated its construction activities to the DDSG­shipyard in Budapest/Óbuda with final assembly at the Naval Arsenal in Pola.

Ganz & Co. ­ Danubius at Fiume had no experience in submarine construction and had to enter an agreement with UBAG, a subsidiary of its competitor Whitehead just a stone throw away. Forced by the lack of skilled labor Danubius had to delegate main works to the DDSG shipyard Budapest/Óbuda where CNT was already engaged in building submarines.

The Stabilimento Tecnico Triestino (STT) had hardly any skilled staff left since most had been members of the Italian minority. Patriotic reasons led to changing the firm's name to Austriawerft A.G. on October 7, 1916.

Despite war induced shortages of materials and skilled labor the shipyards engaged in bitter fights to obtain contracts for submarine construction, never shying away from unfair practices. Hanging over that difficult situation was the demand of the Hungarians to have their quota of 36.4 % of all orders filled. The situation of everybody pitched against everybody led to a waste of resources, a confused construction policy, and development of mini­series of different types competing against each other. Even politicians lost control. In October 1915 they approved construction of two big submarines, laid down, however, were six, none of them ever completed.

Although the government had approved construction of two submarines only by Ganz & Co. ­ Danubius, CNT was negotiating with AG Weser, Bremen since January 1916 to obtain the designs for 800­t submarines. In September the final government letter of approval stipulated that boats built in accordance with these plans should be built at Budapest and assembled in Pola. The A.­H. Navy requested constructive changes not only during the planning stage but also during construction. Together with the shortages of materials it led to further delays: U 48 was about 71%, and U 49 only 54% complete by the end of war. Both submarines were broken up at the shipyards in accordance with stipulations of the peace treaty.

The German Naval Department agreed to let Austria­Hungary have the plans for a 700/840­t submarine on July 11, 1915. Following protracted domestic negotiations, construction by Ganz & Co. ­ Danubius was agreed on February 7, 1916. In November 1918 U 50 was 90%, and U 51 about 60% complete. Both boats were broken up at the shipyard in accordance with stipulations of the peace treaty.

Two more boats of this type got the numbers U 56 and U 57 on September 24, 1918 but construction was never started.

Ganz & Co ­ Danubius had obtained their war time orders. Now the competitors requested consideration. STT and UBAG participated in the tendering procedures of the Fleet Command, with the STT project A 6 declared the winner. The final contract for U 52 and U 53 was issued on August 24, 1918. Hulls of both boats were only 2% complete at the end of the war. On September 24, 1918 numbers U 54 and U 55 were allocated to the same type of submarine.

In May 1916 it was suggested to order submarines of the German UB III type. CNT showed great interest in this up­coming order, bought the license from AG Weser, and offered to build 10 boats of this type. The order was approved by both governments, i.e. the Austrian and Hungarian, with the provision that six boats should be built by Austrian and four by Hungarian shipyards.

U 101 was 47% complete, U 102 by 30%, and U 103 to U 106 by 15% in November 1918. All six boats were broken up on the slip in accordance with stipulations of the peace treaty. The numbers U 118 to U 120 were allocated to three more boats of this type on September 24, 1918 but construction was never started.

As a consequence of CNT receiving a first order of six 500 t boats, the Hungarian part of the Monarchy, i.e. Ganz & Co. ­ Danubius had to get its share under the quota regulation. For this order the Hungarians bought the plans for type UBIII (UB 66­71) from Germany. By November 1918 U 107 was 35%, U 108 by 30%, U 109 by 25%, and U 110 by 20% completed; the four boats were broken up at the shipyard in accordance with the peace treaty. Four more boats received the numbers U 111 to U 114 but construction was never started.

Finally, rather late, the Austria Werft A.G. got into the game. The A.­H. Navy planned to place an order for three 500­t submarines with them, and allocated numbers U 115 to U 117 to the planned boats on September 24, 1918.

Actually the A.­H. Navy disposed of only 27 boats of the above mentioned types during World War I. One fourth of them were lost: U 12 (Lerch) hit a mine on August 12, 1915 while trying to enter the Venice Lagoon (17 dead); U 3 (Strnad) attacked the Italian auxiliary cruiser Città di Catania in the Otranto Straits, was damaged by the enemy ship when it tried to ram the boat, and discovered the following morning by the French destroyer Bisson which sank the damaged boat through gunfire (7 dead); U 6 (Falkenhausen) got entangled in a submarine net at the Otranto barrage, could not free itself and the skipper scuttled the boat when armed trawlers approached; the complete crew was taken prisoner by the Italians; U 16 (Zopa) sank the Italian destroyer Nembo on October 17, 1916 but got rammed by the Italian freighter Borminda, and sank­damaged beyond repair (2 dead), the rest of the crew going into Italian captivity; U 30 (Fähndrich) sailed from Gjenovic/Bocche di Cattaro on March 3, 1917 and was reported missing (21 dead); U 4 (Schlosser) hit a mine on a training cruise in the Canal of Fasana on February 21, 1918 (6 dead), but was salvaged and commissioned again; U 23 (Bézard) was sunk by the Italian torpedo boat Airone with an explosive sweep on February 21, 1918 (21 dead); U 20 (Müller) was sunk by two torpedoes fired by the Italian submarine F 12 off the mouth of the Tagliamento River on June 7, 1918 (18 dead); the wreck was salvaged in June 1962, remains of the crew interred at the burial grounds of the Austrian Military Academy at Wiener Neustadt, the tower is on exhibit at the Austrian Military History Museum, Vienna; U 10 (Sterz) hit a mine off Caorle on July 9, 1918, was beached, subsequently looted by it's own military, towed to Trieste for repairs, but the boat got not back into service till the end of the war.

Due to their modest technical possibilities A.­H. submarines operated mainly in the Adriatic and the eastern Mediterranean, while German submarines, operating out of Austro­Hungarian bases, led warfare throughout the Mediterranean. Nevertheless 108 merchant vessels were sunk by A.­H. submarines with a total displacement of 196,093 GRT, including small coastal sail­ and steamships. Sinking of another 11 merchant vessels of 41,000 GRT is unconfirmed. Enemy warships sank by the A.­H. submarines include the French armored cruiser Leon Gambetta, the Italian armored cruiser Giuseppe Garibaldi, the British destroyer Phoenix, French destroyers Renaudin and Fourche, Italian destroyers Impetuoso and Nembo, the Italian submarine Nereide and the French Cirçé. They damaged the French battleship Jean Bart, the British light cruisers Dublin and Weymouth, and the Japanese destroyer Sakaki. Not bad for a new arm, more or less, established under the restrictive war conditions. This the more when comparing the strength of the Austro­Hungarian submarine fleet with those of its adversaries: France had 79 and Italy 25 submarines at their disposal when war started.

Last Updated: 30 December,2000.

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