HMS A11 was an submarine built for the Royal Navy in the first decade of the 20th century. After surviving World War I, she was sold for scrap in 1920.
A11 was a member of the first British class of submarines, although slightly larger, faster and more heavily armed than the lead ship, . The submarine had a length of 105feet overall, a beam of 12feet and a mean draft of 10feet. They displaced 190LT on the surface and 206LT submerged. The A-class submarines had a crew of 2 officers and 9 ratings.[1]
For surface running, the boats were powered by a single 16-cylinder 6000NaN0 Wolseley petrol engine that drove one propeller shaft. When submerged the propeller was driven by a 150hp electric motor. They could reach 11kn on the surface and underwater.[1] On the surface, A11 had a range of 500nmi at ; submerged the boat had a range of 30nmi at .[2]
The boats were armed with two 18-inch (45 cm) torpedo tubes in the bow. They could carry a pair of reload torpedoes, but generally did not as doing so that they had to compensate for their weight by removing an equal weight of fuel.[3]
A11 was ordered as part of the 1903–04 Naval Programme from Vickers.[4] She was laid down at their shipyard in Barrow-in-Furness in 1903, launched on 8 March 1905 and completed on 11 July 1905.[2]
On 7 September 1910 A11 collided with a barge when leaving Portsmouth Harbour. The barge was sunk, although her two crew were rescued, and A11s bow was slightly damaged.[5] In February 1913, A11 was one of three submarines based at Lamlash on the Isle of Arran off the west coast of Scotland.[6]