S.M. UA (1916)

Germany: Coastal Submersible, ex-Norwegian A5

SM UA was an Imperial German Navy U-Boat of World War I, 5th submarine in the Norwegian A class. She was launched 9 May 1914 but requisitioned by the German government after the started of the war on 5 August 1914. She was then put to German standards and recommissioned as SM U 0 on 14 August 1914, then uniquely renamed “UA” two weeks later. Likewise, she was assigned to coastal protection until transferred to the U-schule (Submarine School) in 1916 and until the end of the war. Furthermore, she was surrendered to the entente powers at Harwich on 24 November 1918 in accordance with the Armistice terms, and attributed to France. She was lost whilst under towing off Folkestone in April 1919 towards the French port, her wrecks identified by archaeologist Innes McCartney in 2013.

Origin: The Norwegian A-class

There is not much to say about the origin of this unique U-Boat, which was unplanned and obtained because of circumstances. Since her design was specific to her Norwegian customer, she never fit in the U-Boat flotilla, too small for practical operations. The Norwegian A class were in effect, the first Norwegian class of submarine before the war, and the only active in WWI. The next class would be a licence-made US L class in Norway in 1920-22. The A class were designed and built at Krupp Germania in Kiel from 1913 to 1914, with three almost completed in 1913 three received before World War I. The fourth, A-5, was seized and became UA. They were tailored for Norwegian needs and thus, quite small, coastal models. Amazingly, they were still active in WW2 and thus, all were lost in the first week of the April 1940 invasion of Norway, one in combat, two by scuttling. They will covered in the future.

Indeed, the Kobben class had the Norwegians very satisfied in 1909, so by November 1910 they sent requests for proposals to German shipyards for more and the best design chosen was from Germaniawerft, an enlarged and more heavily armed version of the Italian “Atropo”. Chief designerwas Dr. Hans Techel. So by May 1911, the Norwegians ordered three, then a fourth in 1912. Kobben was renamed in between A1. She was built in its Köln (Cologne= shipyard under the number 202, keel was laid in October 1912, launched as KNM A-5 on May 9, 1914, but requsitioned in August and completed for the kaiserliches marine later.

Design of the UA

SMS A4 of the Norwegian Navy – the last effectively deliver before the start of the war.

Hull and general design

The coastal nature of these boats, tailored for the Norwegian fjords, made for small and agile models, still with many specifics of usual German models of the time in 1912, but just scaled down in length and in beam. SM. UA indeed displaced 270 t (270 long tons) surfaced and 342 t (337 long tons) submerged for a length of 46.70 m (153 ft 3 in) overall, a beam of 4.78 m (15 ft 8 in) and a draught of 2.80 m (9 ft 2 in). The hull showed a separate deck and hull ballast blisters. The conning tower was very much the same as common U-Boats of the time, with a small helmsman’s post forward and an observation platform, two periscopes (attack and watch) and a single telescopic mast for wireless radio. The hull had two hatches and a torpedo hatch forward. During standardization all Norwegian indications were changed to German, but the torpedo armament remained the same so she was quickly ready for service. Her crew was limited to 18 men and 3 officers.
Other points: Compared to previous Germaniawerft designs she had the stern rudders behind the propellers and was equipped with gyrocompasses, which was rare for such small models. She was a double-hulled coastal model with a diving time of 75 seconds.

Power plant of UA

SM UA being that small, she was almost the size of U1 all the way back in 1906, she only needed moderately powerful diesels: This was a pair of Germania 6-cylinder four stroke Diesel engine with 700 ihp (520 kW) output each, for surface running at 450 rpm and 14.2 knots (26.3 km/h; 16.3 mph). Underwater she was powered by two SSW (Siemens) modyn rated for 380 ihp (280 kW) for 350 rpm submerged at 7.3 knots (13.5 km/h; 8.4 mph). So she was relatively powerful for her displacement and fast with 4600 and 1300 hp respectively total. Her overall range, based on her surface running at 10 knots (19 km/h; 12 mph) with 13 tonnes of diesel oil was rated at 900 nautical miles (1,700 km; 1,000 mi) and 76 nm underwater at 3 knots. Test depth was 50 m (160 ft).

Armament

Torpedo Tubes

SM UA was armed with three 45 cm inches tubes (17.7), two forward and one aft for 5 torpedoes total.

8.8 cm TK L/45 C/14

Unlike the most U-Bootes of the time SM. UA was seen as too small to have a deck armament at all. However in 1917 she was seen as a critical issue and she obtained a 88/42 TK L/45 C/14 deck gun. Some sources also stated she received a defensive AA machine gun on a pintle, removable.

Specs 8.8 cm TK L/45 C/14

Weight 9–10 kg (19.84–22.05 lb) for 88 mm (3.5 in).
Breech: Vertical sliding-wedge, mount −10°/+25°, 15 rpm.
Muzzle velocity: 650 m/s (2,130 ft/s) for 10,694 m (11,695 yd) at +25°

Author’s rendition of SM.UA

⚙ UA specifications
Displacement	270 t (270 long tons) surfaced, 342 t (337 long tons) submerged
Dimensions	46.70 x 4.78 x 2.80 m (153 ft 3 in x 15 ft 8 in x 9 ft 2 in)
Propulsion	2x 700 (520 kW) surfaced, 2x 380 shp (280 kw) submerged, see notes
Speed	14.2 knots surfaced, 7.3 knots submerged
Range	900 nmi at 10 knots, 76 nmi at 3 knots.
Armament	3x 50 cm torpedo tubes +88 mm deck gun 1917, see notes
Max depth	50m (164 ft)
Crew	3 officers, 18 ratings.

Career of S.M. UA class

After the outbreak of World War I, A-5 was requisitioned by the Germans on August 5, 1914, and commissioned into the Kaiserliche Marine on August 14 of that year under the designation SM. U-0 was soon changed to “U-A”. After achieving her combat training she was assigned to the Coastal Defense Division of the Baltic Flotilla. In April 1915, she entered in the Baltic Flotilla’s Reconnaissance Force. In early May, she was selected for an operation to capture the port of Liepāja. On April 27, U-A was sent to Liepāja to observe activities of the Russian fleet. From May 1–5, 1915, U-A accompanied the cruisers SMS Thetis, SMS Lübeck, SMS Augsburg and destroyers from the 10th Flotilla in cover of the minesweeping force clearing the waters near Liepāja, after which she returned to Klaipėda. On May 7, she was sent to patrol the waters of the German port.

After the capture of Liepāja, U-A, together with the coastal battleship “Beowulf” entered the occupied port, stationed as a defensive submarine from then on. On July 2, after the Battle of Gotland, she was reassigned Augsburg to patrol the area further east, but no Russian vessels were spotted. On August 1, she entered the Gulf of Riga for a new patorl. She made a spotting one patrolling torpedo boat launched but missed. She was back to Liepāja at night. In August, U-A was part of the German forces assigned to forcing the Gulf of Riga.

In 1916, she was transferred for training. In 1917, she was rearmed with a 8.8 cm TK C/14 L/45 deck gun with a 108-round ammunition supply in order to train gun crews as well. Following the signing of the Armistice at Compiègne, SM U-A was surrendered on November 24, 1918 to the allies. Subsequently she was attributed to France. Sources diverges here: Some states she was used for testings and scrapped in Toulon in 1920–1921. Conways states she was scrapped in Britain in 1919-20. But modern sources, notably u-boat.net states that indeed she was lost while under tow off Folkestone in April 1919 while being transferred from Harwich to a French port. What was the deciding key was that the wreck was identified by archaeologist Innes McCartney in 2013.

Origin: The Norwegian A-class

Design of the UA

Hull and general design

Power plant of UA

Armament

Torpedo Tubes

8.8 cm TK L/45 C/14

Specs 8.8 cm TK L/45 C/14

⚙ UA specifications

Career of S.M. UA class

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