The Dry Dock, Pant-y-ffynnon Sawmill, was built in 1875-1876 into the platform of Lock 17 to allow easy drainage of water. Its rubble-sandstone eastern side is stopped. Wooden posts, with slotted tops, remained in the centre of the brick-paved floor until at least the 1970s. The posts supported horizontal beams which also rested in the holes on the stopped side. The west vertical wall of the dock has two rows of deep drainage holes and small brick pillars on top to support an overall roof. Two sets of steps provided access. In the south-western stopped corner there was a pitch boiling hearth with a swivelling bar and chain to support a bucket. The lower wall of red brick originally had a vertically-falling sluice gate to dam water in the dock and so allow boats to be floated in and out from the main canal. When the gate was raised a boat could settle on the raised horizontal timbers and the lock bypass water was accommodated in a 1m wide trough on the east side of the dry dock, so that maintenance or building work could proceed. This dock probably replaced the earlier one in the canal depot enclosure was situated conveniently close to the mid-nineteenth century saw mill.
Dry dock SN 7582 0738