 SMU-1 at sea | |
| Class overview | |
|---|---|
| Operators |  Imperial German Navy |
| Preceded by | None |
| Succeeded by | U 2 |
| Completed | 1 |
| Preserved | 1 |
| History | |
 German Empire | |
| Name | U-1 |
| Ordered | 3 December 1904 |
| Builder | Germaniawerft,Kiel |
| Cost | 1,905,000Goldmark |
| Yard number | 119[1] |
| Laid down | October 1905[1] |
| Launched | 4 August 1906[1] |
| Commissioned | 14 December 1906[1] |
| Decommissioned | 19 February 1919[2] |
| Fate | Sustained damage from collision in 1919, subsequently sold toDeutsches Museum |
| Status | On display in theDeutsches Museum inMunich, Germany[2] |
| General characteristics | |
| Class & type | UniqueU-boat |
| Displacement | |
| Length |
|
| Beam | 3.75 m (12 ft 4 in) |
| Draught | 3.17 m (10 ft 5 in) |
| Installed power |
|
| Propulsion |
|
| Speed |
|
| Range |
|
| Test depth | 30 m (98 ft) |
| Complement | 2 officers, 10 men (later 3/19) |
| Armament | 1 × 45 cm (17.7 in)torpedo tube with 3 C/03torpedoes |
| Service record | |
| Part of |
|
| Operations | none |
| Victories | No ships sunk or damaged |
SMU-1 is the firstU-boat produced for theGerman Empire'sImperial German Navy. TheU-1 was constructed byGermaniawerft inKiel and wascommissioned on 14 December 1906. The main purpoose of the U-1 was to gain operational experience withsubmarines and to test novel equipment. WhenWorld War I began in 1914, theU-1 was deemed obsolete and was used for training until 19 February 1919, when it was struck by another vessel while on an exercise.
At the beginning of the 20th century, when submarine development gathered pace, the commander of theImperial German NavyAlfred von Tirpitz was reluctant to participate in it; instead he focussed on building theHigh Seas Fleet with which he intended to challenge the supremacy of theRoyal Navy, and saw no role for submarines in his fleet. Only whenKrupp received an order for threeKarp-class U-boats from Russia, did Tirpitz order a first submarine, theU-1.[3][4]
TheU-1 was a redesigned Karp class submarine by Austrian-born Spanish{{sfn|Polanco Mansa|}
} engineerRaimundo Lorenzo de Equevilley Montjustín [de] working for the German shipbuilding companyFriedrich Krupp Germaniawerft.[5] The main improvements over the exportKarp class included trim tanks instead of a moveable weight, a redesigned forecastle to improve seagoing ability, a 10 cm (3.9 in) larger diameter, a strengthenedpressure hull, fuel tanks installed externally to avoid leakage throughrivets, a rearrangement of the internal equipment and a strongerballast keel.[6]
U-1 had a double hull, the inner pressure hull was 32.50 m (106 ft 8 in) long and was cylindrical with a maximum diameter of 2.80 m (9 ft 2 in) . the outer hull had anoverall length of 42.39 m (139 ft 1 in), with abeam of 3.75 m (12 ft 4 in) (o/a) .[2][7] The pressure hull was made of 12 mm (0.47 in) thick steel, with 1.60 m (5 ft 3 in) distance between frames. The outer hull was made of standard 3.5–4 mm (0.14–0.16 in) thick steel ( as used ontorpedo boats ) with a zinc coating at both sides.[8]U-1 had adraught of 3.17 m (10 ft 5 in), shedisplaced 238 tonnes (234 long tons) when surfaced and 283 t (279 long tons) when submerged.[2][7]
The rudder was placed forward of the propellor. In order to minimize heeling during submerged manoeuvres, there was also a rudder mounted at deck level. These rudders were manually operated. Both the left and right forwardhydroplanes were mounted on a common rudderspindle running through the pressure hull in acollar. Constructional diving depth[a] was 30 m (98 ft 5 in).[8]
U-1 was armed with one 45 cm (17.7 in)torpedo tube fitted in thebow and carried 3 C/03torpedoes.[2][7][8] The total cost amounted to 1,905,000Mark (equivalent to €11,620,000 in 2016).[9][2]
The Imperial German Navy avoided the use ofgasoline due to the perceived risk of fires and explosions that had caused many accidents in early submarines, and instead of the gasoline engines that had powered theKarp boats,U-1 was given much saferKörtingkerosene engines. While normally kerosene engines were started using gasoline, theU-1's engines avoided even this and instead used electrically-heated air.[10]
The Körting engines could not be reversed, and could only run at full speed, since their rpm could not be varied to any useful extent, and as a consequenceU-1 was fitted withVariable-pitch propellers to allow her speed to be controlled.[11] These variable pitch- propellers were abandoned in subsequent designs due to their poor efficiency.[12] Althoughdiesel propulsion had already been considered for the preceding Karp-class U-boats, the kerosene-electric propulsion continued to be used forU-1, and in the following years. Diesel engines became finally available in 1912-1913 and were installed from theU-19 class onwards.[13]U-1 was fitted with twoKörting 6-cylinder two-stroke kerosene engines with a total of 400metric horsepower (294 kW; 395 bhp) for use on the surface .These engines powered two shafts, which gave the boat a top surface speed of 10.8knots (20.0 km/h; 12.4 mph) and a cruising range of 1,500nautical miles (2,800 km; 1,700 mi) at 10 kn (19 km/h; 12 mph).
For submerged propulsionU-1 had twoGarbe, Lahmeyer. double-actingelectric motors with a total of 300 kW (408 PS; 402 shp). These engines were not designed for U-boats but were rather large sized land-based machinery. They were open and had no protection against dripping water nor mechanical damage. The electrical engines gave the boat a top speed of 8.7 knots (16.1 km/h; 10.0 mph) when submerged, and a range of 50nautical miles (93 km; 58 mi) at 5 kn (9.3 km/h; 5.8 mph).[2][14][8] Power for the electrical engines was provided by aAFAlead-acid battery consisting of cells with mass plates andpeat fibre insulation. One cell measured 55.5 cm (21.9 in) by 40 cm (15.7 in) by 25 cm (9.8 in) and could provide 715Ampere-hour for ten hours. These heavy cells were stacked in layers, resulting in a too high center of gravity. This was compensated by a 23 t (23 long tons) leadballast in thekeel.[15][16] This type of battery cell was not successful because of problems with the peat insulation. The peat insulation overheated when the battery discharged at full capacity and due to the limited mobility of the acid in the peat insulation, the battery plates were unevenly charged which reduced the life of the battery.[15]
U-1 was ordered on 3 December 1904 from the Germaniawerft.[17] She was commissioned on 14 December 1906,[18] and with this occasion, Germany was the last major navy to adopt submarines.[3] The boat was lifted into the water on 4 August 1906 and began its trials, a year later than originally planned. The salvage shipOberelbe loweredU-1 to a depth of 30 m (100 ft), first without crew and then, when the pressure hull was found to be safe, with a crew.[19]
The U-boat was thoroughly tested in the calm waters ofEckernförde during the following year. Based on experiences some minor improvements were implemented.[20] During the Kiel Naval Week in March 1907, the commander was decorated with theOrder of the Red Eagle for hitting with two exercise torpedoes thelight cruiserMünchen on whichKaiserWilhelm II was embarked.[21] In August 1907, the boat proved its seaworthiness by sailing autonomously fromWilhelmshaven aroundDenmark toKiel in very adverse weather. The original crew of twelve was expanded to twenty-two in order to cope with all the necessary duties.[20]
U-1 was used for crew training and as a test boat. She did not see active service during World War I.[22] After suffering damage from a collision while on a training exercise in 1919,U-1 was sold to the Germaniawerft foundation at theDeutsches Museum inMunich where it was restored and can be viewed on display. A large portion of the starboard hull has been removed to allow visitors to see the submarine's interior.[23]
Media related toSM U 1 (submarine, 1906) at Wikimedia Commons