to buckle the ship. Efforts by hydraulic jacks and tugboats failed to get her into the water on the next spring tide failed, but the use of pontoons on 17 April 1866 proved successful. Her builders went into bankruptcy while the ship was being launched and the liquidators seized Northumberland as a company asset once she was in the water. Eight months passed before the Admiralty could take possession and begin fitting out the ship. She was commissioned in October 1868 and completed on 8 October for a cost a total of £444,256. The ship's first posting was to the Channel Squadron, where she remained until 1873. Her first captain, Roderick Dew, had all of her yards painted black so that she could be visually distinguished from her half-sisters, whose yards were white. During this time she helped her half-sister tow a floating drydock from England to Madeira where it would be picked up by and and taken to Bermuda. The ships departed the Nore on 23 June 1869, loaded down with of coal stowed in bags on their gun decks, and transferred the floating dock 11 days later after an uneventful voyage. She was anchored at Funchal, Madeira, on Christmas Day 1872, when a storm parted her anchor chain and the ship drifted onto the ram bow of the ironclad . Northumberland was seriously damaged below the waterline, with one compartment flooded, though she was able to steam to Malta for repairs. While her half-sister , normally flagship of the Channel Squadron, was refitting in 1873–75, Agincourt, normally the flagship of the fleet second-in-command, replaced her as flagship and Northumberland became flagship of the second-in-command until Minotaurs return to duty. She served as the flagship for Rear Admirals George Hancock and Lord John Hay. Northumberland received her own refit and rearmament from 1875 to 1879 and rejoined the Channel Squadron upon its completion. The ship was paid off in 1885 for another refit and became the flagship of Vice Admirals Sir William Hewett and John Baird, successive commanders of the Channel Squadron, upon her completion in 1887. Northumberland was assigned to the 1st Reserve Squadron at the Isle of Portland in 1890–91 and then at Devonport from 1891 to 1898. She was hulked in 1898 as a stokers' training ship at the Nore and renamed Acheron on 1 January 1904. From 1909 to 1927 the ship served as a