Along with the new dock, Dummer proposed that two wet docks (non-tidal basins) be built: the first ("Lower") Wet Dock was entered directly from the harbour and provided access to the Great Stone Dock; since much expanded, it remains in place (now known as "No. 1 Basin"). The second ("Upper") Wet Dock was entered by way of a channel. To empty the dry dock, Dummer designed a unique system which used water from the Upper Wet Dock to drive a water-wheel on the ebb tide, which in turn powered a set of pumps. (At high tide, an auxiliary set of pumps was used, powered by a horse gin.)