B1 1905
| Name | No | Yard No | Builder | Laid down | Launched | Comp | Fate |
| B1 | I21 | Vickers, Barrow | 1903 | 25.10.1904 | 4.1904 | sold 8.1921 | |
| B2 | Vickers, Barrow | 1904 | 30.10.1905 | 12.1905 | collision 4.10.1912 | ||
| B3 | I23 | Vickers, Barrow | 1904 | 31.10.1905 | 1.1906 | sold 12.1919 | |
| B4 | I24 | Vickers, Barrow | 1904 | 14.11.1905 | 1.1906 | sold 4.1919 | |
| B5 | I25 | Vickers, Barrow | 1904 | 14.11.1905 | 2.1906 | sold 8.1921 | |
| B6, 8.1917- S6 | I26 | Vickers, Barrow | 1904 | 30.11.1905 | 3.1906 | patrol boat 8.1917, sold 1919 | |
| B7, 8.1917- S7 | I27 | Vickers, Barrow | 1904 | 30.11.1905 | 3.1906 | patrol boat 8.1917, sold 1919 | |
| B8, 8.1917- S8 | I28 | Vickers, Barrow | 1905 | 23.1.1906 | 4.1906 | patrol boat 8.1917, sold 1919 | |
| B9, 8.1917- S9 | I29 | Vickers, Barrow | 1905 | 24.1.1906 | 4.1906 | patrol boat 8.1917, sold 1919 | |
| B10 | I20 | Vickers, Barrow | 1905 | 23.3.1906 | 5.1906 | sunk 9.8.1916 | |
| B11, 8.1917- S11 | I00 | Vickers, Barrow | 1905 | 21.2.1906 | 7.1906 | patrol boat 8.1917, sold 1919 |
|
Displacement standard, t |
|
|
Displacement normal, t |
287 / 316 |
|
Length, m |
43.3 |
|
Breadth, m |
4.12 |
|
Draught, m |
3.43 |
|
No of shafts |
1 |
|
Machinery |
1 Vickers petrol engine / 1 electric motor |
|
Power, h. p. |
600 / 290 |
|
Max speed, kts |
12 / 6 |
|
Fuel, t |
petrol 16 |
| Endurance, nm(kts) | 1000(8.7) / |
|
Armament |
2 - 450 TT (bow, 4) |
|
Complement |
15 |
| Diving depth operational, m | 30 |
Project history: The successors to the 'A' class were very similar, the main improvements being the provision of a more substantial deck casing to improve surface performance and a bigger reserve of buoyancy. They were also fitted with a pair of hydroplanes at the forward end of the conning tower to improve underwater handling. This innovation was not repeated in subsequent classes, but 50 years later it was reintroduced in US nuclear submarines for the same reason.
Modernizations: 1917, S6-9, 11: were converted to surface patrols, electric motors were removed; + 1 x 1 - 76 12pdr 12cwt QF Mk.I/II
Naval service:
The six boats went to the Mediterranean were not employed after the autumn
of 1915 for lack of spares, and in order to make better use of them the
Admiralty arranged with the Italian Navy to rebuild them as surface patrol boats
at Venice in 1917. This involved removing the electric motors and batteries and
building up the bow casing to form a forecastle. A small wheelhouse was
provided, and 2 platform for a 12pdr gun. No note survives about their torpedo
armament but presumably the tubes were not used. As S6-11 these patrol
craft were employed in the Adriatic, and the survivors were sold at Malta in
1919.
B2 was sunk in collision with SS Amerika in the
Dover Strait 4.10.1912. B10 was sunk in Venice DYd while undergoing
conversion to surface patrol boat 9.10.1916, by Austrian bombing attack. B11
was sent to the Mediterranean late in 1914, and on 1 December negotiated Turkish
minefields and nets to sink the coast defence ship Messudieh.
B2 1900s
© Ivan Gogin, 2008-13