1865. By 1861, No 1 Dock had been filled in and a machine shop constructed in its place for heating, bending and planing armour plate for HMS Achilles which was being built alongside. For the time being, however, marine steam engines were not manufactured on site but were ordered from Thames-based private contractors (along with other associated equipment). In 1860 the dockyard's policing was also transferred to the new No.4 Division of the Metropolitan Police, which remained in that role until 1932. Expansion A significant disadvantage for Chatham was that fitting out had always taken place on the river. When Achilles, for example, had been completed and floated out of dry dock, she spent almost a year moored in Gillingham Reach, where not only her engines, boilers, funnels and a propeller, but also masts, sails, rigging, guns, coal, food, ammunition and furnishings were either loaded or installed. It was partly to address this problem that the Admiralty undertook a huge building programme at Chatham, between 1862 and 1865, which quadrupled the size of the yard and provided specialist facilities for steam-powered ships with metal hulls. Three basins were constructed along St Mary's creek, from west to east: No 1 Basin (of ), No 2 Basin () and No 3 Basin (). Along the southern edge of No 1 Basin four new dry docks were built (Nos 5–8), each long. Initially a purpose-built 'steam factory' was planned, but following the closure of Woolwich Dockyard in 1869 a number of slip covers were removed from that site and re-erected at the head of the new dry docks to serve as factories for building and fitting engines and for boilermaking. No 1 Basin was officially opened in 1871, with HMS Invincible being brought into No 5 Dock for repairs, with great ceremony. Work on the other docks and basins followed, with No 3 Basin finally being completed in 1883. Two years later the project was largely complete, with facilities provided alongside for gun mounting and mast rigging, as well as a victualling depot and a coaling area. Much of the excavation and building work had been done by convict labour (a convict prison having been built to the north of the dockyard, with the expansion project in mind, in 1853). In 1897 a naval barracks was built on the site of the prison to provide crew accommodation for ships anchored in The Nore;