in the Navy and operated at what would even then would have been considered a relatively low pressure, for more modern boilers, of . The boiler was repaired and the ship was completed on 26 May 1877 at a cost of £368,428.Thunderer was commissioned in May 1877 for service with the Reserve Fleet Particular Service Squadron and was then assigned to the Channel Squadron. During this time, she was fitted with experimental torpedoes. She sailed for the Mediterranean in 1878 under the command of Captain Alfred Chatfield. Leaving Gibraltar for Malta in November 1878, Thunderer ran aground and was damaged. She was refloated and resumed her voyage. She was repaired at Malta. The ship suffered another serious accident on 2 January 1879, when the left 12-inch 38 ton gun in the forward turret exploded during gunnery practice in the Sea of Marmora, killing 11 and injuring a further 35. The muzzle-loading gun had been double-loaded following a misfire. According to Admiral of the Fleet E.H Seymour, "Both turret guns were being fired simultaneously, and evidently one did not go off. It may seem hard to believe such a thing could happen and not be noticed, but from my own experience I understand it. The men in the turret often stopped their ears, and perhaps their eyes, at the moment of firing, and then instantly worked the run-in levers, and did not notice how much the guns had recoiled. This no doubt occurred. Both guns were at once reloaded, and the rammer's indicator, working by machinery, set fast and failed to show how far the new charge had gone." The accident contributed to the Royal Navy changing to breech-loading guns, which could be more conveniently worked from inside the turrets. The fragments of the destroyed gun were re-assembled and displayed to the public at the Woolwich Arsenal. The committee of inquiry decided that the gun had been double-loaded, but this view was widely questioned, including by Sir William Palliser, designer of the Palliser shell used by these guns. Palliser's view instead was that the shot had been obstructed by a portion of the millboard disc rammed above the shell. Hydraulic power-ramming was thought to be implicated in the double loading as the telescopic hydraulic rammer had not made the double loading obvious, as a manual ramrod would have done. One piece of evidence supporting the double loading theory was the presence