HMS Penelope was a central-battery ironclad built for the Royal Navy in the late 1860s and was rated as an armoured corvette. She was designed for inshore work with a shallow draught, and this severely compromised her performance under sail. Completed in 1868, the ship spent the next year with the Channel Fleet before she was assigned to the First Reserve Squadron in 1869 and became the coast guard ship for Harwich until 1887. Penelope was mobilised as tensions with Russia rose during the Russo-Turkish War of 1877–78 and participated in the Bombardment of Alexandria during the Anglo-Egyptian War of 1882. The ship became a receiving ship in South Africa in 1888 and then a prison hulk in 1897. She was sold for scrap in 1912. Design The chief constructor, Sir Edward Reed, was ill, so the design of this ship was entrusted to his assistant and brother-in-law, Nathaniel Barnaby, himself a future chief constructor. For reasons that have not survived, the Admiralty required that Penelope to be a ship of unusually shallow draught, possibly in light of the operations in the shallow Baltic Sea during the Crimean War of 1854–1855. The ship was long between perpendiculars and had a beam of . She had a draught of forward and aft. Penelope displaced and had a tonnage of 3,096 tons burthen. She had a complement of 350 officers and ratings. She was the first British capital ship to be fitted with a washroom. Penelope had a pair of Maudslay three-cylinder, horizontal-return, connecting-rod steam engines, each driving a single propeller. The engines used steam provided by four boilers with a working pressure of . The ship reached a speed of from during her sea trials on 1 July 1868. She carried a maximum of 500 tons of coal, enough to steam at . The shallow-draught requirement forced Barnaby to build her with twin screws, as a single screw of larger diameter would have been mounted insufficiently deep to be effective. The Admiralty also wanted hoistable propellers as the reports from and , with their fixed propellers, were distinctly uncomplimentary about their sailing qualities. She was the only twin-screw ship ever to have hoisting screws. Provision for the hoisting frames and twin rudders forced a very unusual shape to the stern, which unintentionally greatly increased drag. The other issue was that the shallowness of her draught made her very unhandy under sail,