Before 1814 timber was hand sawn by about 150 Sawyers employed at Chatham Dockyard.There was two Sawyers to each piece of timber,one man above the timber and the other in a pit below.The man above was known as the "Top dog" and was the more skilled of the two, he was responspible for setting and guiding the saw.While the man below in the pit was paid less and was known as the "Under dog" he also got the unpleasant job of getting covered in sawdust.
Moving timber around the Dockyard was done by men and horses to and fro from the stacking places,this cost about £4000 in wages alone.
In 1812 work started on a Steam-powered Sawmill designed by Marc Brunel (Father of Isambard Kingdom Brunel).Brunel designed a sawing hall with a pitched roof and two open sides.At each end were two 3 storey wings,in one of these was the boiler and engine house.On the wing at the other end on the roof was supported a large cast-iron water-tank.
The Sawmill was to be built on a hill just outside the Dockyards old wall and the land had to be purchased specially.Brunel insisted "That hill must be bought" as he could see the advantages of having the sawmill at that location.
Marc Brunel planned a canal and canal tunnel over 300 ft long to link the South Mast Pond to a deep oval brick lined Shaft just in front of the wated-tank at the Sawmill.
Unfortunatly during construction of the tunnel and sawmill Marc Brunel was not given overall control of the building work.For his tunnel he designed an elliptical arch but this was changed in his absence to a vertical segmant design. Due to this weaker design and poor workmanship of the bricklayers a 45 foot section of the tunnel colapsed killing one man and injuring 10 others.Also there was problems with the 120 foot chimney on the Sawmill that saw Brunel and the authorities in contention.Brunel observed the chimney had cracks and was bulging outwards so building work was halted to the annoyance of the authorities.Butresses and wrought iron ties were installed to make the Chimney safe.
When the Sawmill and Canal were completed and opened in 1814 Timber could be floated through the Canal and tunnel to the shaft at the base of the sawmill.Then a counterpoise could be filled with water from the water-tank above to raise the timber up to the surface where it was grabbed by a crane which travelled on a gantry and the wood was lowered onto a carriage.
Inside the 90 foot square sawing room of the sawing mill were 8 vertical saw frames,each capable of carrying one to 36 saws.There was also 2 circular saw benches to cut the wood to the required widths.Windlasses and Capstans were used to move the wood inside the Sawmill,powered by the steam engine.Saws were driven at 80 strokes per minute by the Beam Steam engine.When the wood was sawn into planks it was loaded onto a carriage and taken to a timber seasoning shed.
The Sawmill and its moving of timber systems revolutionised working of wood at the dockyard,it saved much money and boosted production.It is said when the saws were running the high pitched note could be heard in the town and over the river.
When the Sawmill was closed it was used for various things.During the early part of the 20th century the basement was converted into a steam laundry which was used up untill the dockyards closure. In World War II the tunnel was converted into the "Yard H.Q." and used for Passive Defence,to co-ordinate Civil Defence within the Naval area.
Below are some photo's of inside the tunnel.
The South Mast Pond and Canal have been filled in,the South Mast pond is now the visitors car park.(The Sawmill can just be made-out in the trees)
Today the Sawmill is used by North Kent Joinery Ltd.
"Although the outside is viewable from the Dockyard the Sawmill is not generally open to Dockyard visitors.The tunnel is also not open to visitors."
Many thanks to the worker who gave us permission to look inside the tunnel and also to the Armchair explorer.