Type UB I submarine

The Type UB I submarine was a class of small coastal submarines built in Germany at the beginning of the First World War. Twenty boats were constructed, most of which went into service with the German Imperial Navy Boats of this design were also operated by the Austro-Hungarian Navy and the Bulgarian Navy. In the Austro-Hungarian Navy, it was called the U-10 class.
Built to meet the need for small maneuverable submarines able to operate in the narrow, shallow seas off Flanders, the vessels were intended to be quickly constructed, then shipped by rail and assembled at their port of operation. The design effort began in mid-August 1914 and by mid-October the first 15 boats were ordered from two German shipyards. The German Imperial Navy subsequently ordered an additional pair of boats to replace two sold to Austria-Hungary, who ordered a further three boats in April 1915 for a total of 20 UB Is built.
Construction of the first boats for Germany began in early November 1914; all 20 were completed by October 1915. Several of the first boats underwent trials in German home waters, but the rest were assembled and tested at either Antwerp or Pola. The German boats operated primarily in the Flanders, but also in the Baltic, Pola and Constantinople Flotillas. The boats were about long and displaced when surfaced and while submerged. All had two bow torpedo tubes and two torpedoes, and were equipped with a deck-mounted machine gun.
In 1918 four of the surviving German boats were converted into coastal minelayers. Of the seventeen boats in German service, two were sold to Austria-Hungary, one was sold to Bulgaria, and nine were lost during the war. One of the five Austro-Hungarian boats was sunk and another mined and not repaired. The five surviving German boats, the four surviving Austro-Hungarian boats, and the Bulgarian boat were all turned over to the Allies after the end of the war and were broken up.

Design

In the earliest stages of the First World War, the German Army's rapid advance along the North Sea coast found the German Imperial Navy without submarines suitable to operate in the narrow and shallow seas off Flanders. By 18 August 1914, two weeks after the German invasion of Belgium, the planning of a series of small coastal submarines had already begun.
The German Imperial Navy stipulated that the submarines must be transportable by rail, which imposed a maximum diameter of. The rushed planning effort—which had been assigned the name "Project 34"—resulted in the Type UB I design, created specifically for operation from Flanders. The boats were to be about long and to displace about with two bow torpedo tubes.

Characteristics

On 15 October, eight Type UB I – were ordered from Germaniawerft Kiel and seven Type UB I – from AG Weser of Bremen. The Germaniawerft-built boats at length overall, were longer than the AG Weser-built boats. All were abeam, had a draft of, a height of and a constructional diving depth of. The boats all had a pressure hull with a length of, displaced while surfaced, but while submerged UB-1 - UB-8 displaced whilst UB-9 - UB-17 displaced. The former had an average diving time of twenty to thirty-three seconds, whilst the latter had an average diving time of twenty-two to thirty-three seconds.
The drivetrain of the boats consisted of a single propeller shaft driven by a four-cylinder, four-stroke RS164 Daimler or Körting diesel engine on the surface, or a Siemens-Schuckert electric motor for underwater travel. UB-1 - UB-8 had a top surface speed of, and when submerged. Cruising range was at on the surface and at submerged. UB-9 - UB-17 boats were capable of on the surface and submerged. Cruising range was at on the surface and at submerged. The boats were equipped with two bow torpedo tubes and carried just two C/03 torpedoes. They were also armed with a single machine gun affixed to the deck. Type UB I U-boats had a complement of one officer and thirteen men.
The boats were equipped with compensating tanks designed to flood and offset the loss of the C/03 torpedo's weight when these were fired, but this system did not always function properly; as a result, when firing from periscope depth the boat could broach after firing or, if too much weight was taken on, plunge to the depths.

Further development

Apart from the projected type UB I, the German Navy wanted also to deploy minelaying U-boats against England, from the same ports in Flanders. In order to speed up the design, the Type UB I was taken as a basis for the minelayer design. The forward half of the hull was modified to house six mineshafts instead of two torpedo tubes. Crew accommodation became even more cramped as there was no place anymore for bunks in the forward compartment. The first of these Type UC I U-boats were already ordered on 15 October 1914.
In the spring of 1915, it became clear that the war would continue well into 1916, and more coastal U-boats were ordered. The Type UB I had fulfilled the expectations but had some problems: it was underpowered and could often not cope with the strong currents present in the English Channel and before the Belgian and English coast. They did not have enough power to chase down steamers while surfaced and lacked the endurance to spend any extended amount of time underwater, exhausting their batteries after little over an hour's running. In-service use revealed another problem: with a single propeller shaft/engine combination, if either component failed, the U-boat was almost totally disabled. To address these problems, the next class of coastal U-boats, the Type UB II needed to be much larger and the Type UB I was not further developped.
As a stopgap messure, four Type UB I U-boats were converted into minelayers, by increasing the hull length to, and replacing the forward torpedo compartment with four mineshafts that could contain eight mines.

Construction

The German Imperial Navy ordered its first fifteen Type UB I boats on 15 October 1914. Eight boats—numbered UB-1 to UB-8—were ordered from Germaniawerft of Kiel, and seven boats—numbered UB-9 to U-15—from AG Weser of Bremen. After two of the class, UB-1 and UB-15, were sold in February 1915 to ally Austria-Hungary, the German Imperial Navy ordered ' and ' from Weser. A further three for Austria-Hungary —U-15, U-16, and U-17—had been ordered from Weser by April, bringing the total number constructed to 20.
UB-1 and UB-2 were laid down on 1 November 1914 at the Germaniawerft yard at Kiel. UB-1 was launched on 22 January 1915, just 75 working days later. UB-2s launch followed on 13 February. Among the Weser boats, UB-9 was laid down first, on 6 November 1914, and launched on 6 February 1915, a week ahead of UB-2. These first three boats launched underwent trials in home waters, but most of the other members of the class were shipped via rail and underwent trials at their assembly point.
The process of shipping the submarines by rail involved breaking the submarines down into what was essentially a knock down kit. Each boat was broken into approximately fifteen pieces and loaded onto eight railway flatcars. Type UB I boats destined for service with the Flanders Flotilla made a five-day journey to Antwerp for the two- to three-week assembly process. After assembly at Antwerp the boats were towed by barge to Bruges for trials. Boats selected for service in the Mediterranean were sent to the Austro-Hungarian port of Pola for assembly. The total time from departure of the railcars from the shipyard to operational readiness for the boats was about six weeks.
By July 1915, all seventeen of the German Imperial Navy Type UB Is had been completed.

History

The Type UB I were in active service from March 1915 through the end of the war, with half of the 20 boats lost during the war. Boats of the class served in three navies: the German Imperial Navy, the Austro-Hungarian Navy, and the Bulgarian Navy. In German service, they served primarily in the Flanders Flotilla, the Baltic Flotilla, and the Constantinople Flotilla.

Name	Date launched	Date commissioned	merchant ships sunk	warships sunk	Fate
UB-1			none	1/120	Commissioned on 12 July 1915 in the Austro-hungarian Navy as U-10. Handed over to Italy as a war reparation and scrapped at Pola by 1920.
UB-2			11/1.378	none	Broken up by Stinnes in 1920.
UB-3			none	none	Disappeared after 23 May 1915.
UB-4			3/10.883	none	Sunk by gunfire by HM Armed Smack Inverlyon'', a British Q ship on 15 August 1915.
UB-5			5/996	none	Broken up by Dräger at Lübeck in 1919.
UB-6			16/7.007	1/480	Scuttled by her crew at Hellevoetsluis, Netherlands on 18 March 1917. Her wreck was later raised and broken up at Brest in July 1921.
UB-7			1/6.011	none	Disappeared after 27 September 1916.
UB-8			1/19.380	none	Commissioned on 26 May 1915 in the Bulgarian Navy as Podvodnik No. 18. Handed over to the French on 23 February 1919. Later towed to Bizerta, where she was scrapped after August 1921.
UB-9			none	none	Broken up by Dräger at Lübeck in 1919.
UB-10			36/22.583	1/1.072	Scuttled off Flanders on 5 October 1918.
UB-11			none	none	Broken up by Stinnes in 1920.
UB-12			22/10.234	none	Disappeared after 19 August 1918.
UB-13			11/17.674	none	Sunk after 23 April 1916.
UB-14			4/13.622	3/11.720	Scuttled off Sevastopol in the Black Sea in 1919.
UB-15		4 April 1915	none	1/250	Commissioned on 18 June 1915 in the Austro-Hungarian Navy as U-11. Handed over to Italy as a war reparation and scrapped at Pola in 1920.
UB-16			25/18.825	1/1.075	Sunk by torpedo by HMS E34 on 10 May 1918 in the North Sea.
UB-17			13/2.274	none	Disappeared after 11 March 1918 off Flanders

Name	Date commissioned	merchant ships sunk	warships sunk	Fate
U-15		5 / 8.044	1 / 720	Handed over to Italy as a war reparation and scrapped at Pola in 1920.
U-16		2 / 87	1 / 325	Sunk on 17 October 1916.
U-17''		1 / 40	1 / 672	Handed over to Italy as a war reparation and scrapped at Pola in 1920.