To deal with the increasing number of docks, Bentham in 1797 proposed replacing one of the horse pumps above the reservoir with a steam engine. His plan was that the engine should be used not only to drain the reservoir (by night) but also to drive a sawmill and woodworking machinery (during the day); he also envisaged linking it to a freshwater well, to enable water to be pumped through a network of pipes to various parts of the dockyard. A table engine, designed by Bentham's staff chemist James Sadler, was installed in 1799; it represented the first use of steam power in a Royal Naval Yard. By 1800 a second steam engine (a Boulton & Watt beam engine) was being installed alongside the first. Meanwhile, Bentham designed and built a series of subterranean vaulted chambers over the reservoir, upon which he erected a pair of parallel three-storey workshops to contain reciprocating and circular saws, planning machines and morticing machines, built to his own designs, to be driven by the two engines (which were accommodated together with their boilers in the south workshop). Tanks installed on the upper floor provided a head of water for Bentham's aforementioned dockyard-wide pipe network, providing both salt water for firefighting and fresh water for various uses (including, for the first time, provision of drinking water to ships on the wharves) sourced from a newly sunk 274 ft well.
