U5 1914
U12 1915
| Name | No | Yard No | Builder | Laid down | Launched | Comp | Fate |
| U5 | Whitehead, Fiume | 4/1908 | 10.2.1909 | 4/1910 | to Italy 1920 | ||
| U6 | Whitehead, Fiume | 2/1908 | 12.9.1909 | 7/1910 | sunk 10.5.1916 | ||
| U12 (ex-U7, ex-SS3) | Whitehead, Fiume | 1910 | 14.3.1911 | 1911 // 8.1914 | sunk 12.8.1916 |
|
Displacement normal, t |
U5, 6: 236 / 273 U12: 240 / 270 |
|
Displacement full, t |
|
|
Length, m |
32.1 |
|
Breadth, m |
4.23 |
|
Draught, m |
3.90 |
|
No of shafts |
2 |
|
Machinery |
2 petrol engines / 2 electric motors |
|
Power, h. p. |
U5, 6: 400 / 230 U12: 400 / 220 |
|
Max speed, kts |
U5, 6: 10.1 / 9 U12: 10 / 8 |
|
Fuel, t |
petrol |
|
Endurance, nm(kts) |
2500(7) / 60(3) |
|
Armament |
2 - 450 TT (bow, 4) |
|
Complement |
U5, 6: 19 U12: 17 |
|
Diving depth operational, m |
50 |
Project history: These boats were built by the Fiume-based firm of Whitehead which had bought a license from the Irish-American John Philip Holland to build his submarines. The first two boats were partially assembled in the United States and assembled at Whitehead's, which caused a lot of trouble. The third boat was built on speculation and featured improvements in all the mechanical and electrical systems. Named S.S.3 this unit was offered to the Austrian Navy too, but she was refused because the trials programme was not yet completed. Whitehead then offered the boat to the navies of Peru, Portugal, Netherlands, Brazil, Bulgaria and again to the Austro-Hungarian Navy. When war broke out Austria bought the unsold boat and provisionally commissioned her as U7, but by the end of August 1914 she was definitely commissioned as U12. The single-hulled Holland type featured a distinctive tear-drop hull and an interesting design of the TT hatches: these were clover-leaf shaped and rotated on a central axis.
Modernizations: 11.1914, U5; 12.1914, U12, 12.1915, U6: + 1 x 1 - 37/20 SFK L/23 H
early 1915, U12: petrol engines were replaced by diesels (600hp)
1917, U5: - 1 x 1 - 37/20; + 1 x 1 - 75/27 G. L/30 K.16 BAG
Naval service: All three saw active war service. U5, sunk after hitting a mine during trials on 16 May 1917, was raised and rebuilt with a conning tower and a 7.5cm/30 gun; she was ceded as a war reparation to Italy in 1920 and scrapped. U6 was trapped in submarine nets during an attempt to break through the Otranto barrage and scuttled by the crew 10.5.1916. U12 was sunk with the loss of all hands by a mine when trying to penetrate the harbour of Venice, about 12 August 1916. Raised by Italy at the end of 1916 she was scrapped in the Venice N Yd.
U5 1915
U6 1916
© Ivan Gogin, 2014