The tests were severe, but they proved more effectively than any tests before had done the great superiority of the independent acting twin screw over the single screw; and the results in far greater manœuvring power, speed, and reliability were so satisfactory that the Admiralty was most favourably impressed. The Messrs. Dudgeon, in 1863, built the steamship _Far East_, and her launch and trial trip took place in the presence of the representatives of the Admiralty. She was fitted with twin screws which had a diameter of 8 feet 2 inches, and a pitch of 16 feet. The shafts of the screws were carried through a wrought-iron tube bolted to a false iron bulkhead clear of the ship’s frame. The Admiralty not long afterwards adopted twin-screw propellers. The advantages of the twin screw were that were one to be disabled, the other could propel the ship without trouble, and that as an aid to steering, one screw could be sent astern and the other worked ahead, so as to turn the vessel in little more than her own length. The _Penelope_, launched in 1867, was the first twin-screw ocean-going ironclad belonging to the Navy, and she was, moreover, the first government owned warship in which each screw had its own engine, as compared to the two screws geared to one engine in the floating batteries of the Crimean days. She was of 4,470 tons displacement, and her engines of 4,700 indicated h.p. gave her a speed of between twelve and thirteen knots. Each of her twin screws was fitted to a distinct stern with separate deadwood and rudder, an arrangement which neither added to the steering capabilities of the ship nor increased its structural strength at the stern. The _Penelope_ had recessed ports to allow of increased training of the guns.