As a riverside industrial town with two naval dockyards and some of the activities of a busy port Greenwich is somewhere with a use for tar. After all sailors have been known as ‘Jolly Jack Tars’. What we think of today as tar is largely that made from coal and as by-products of gas coal gas manufacture. That has clearly only been around since about 1820 and before then what was used was called Stockholm Tar which imported from Sweden and Russia and was a derivative of wood. Cheap coal tar came to have a number of uses which were primarily a way of proofing wood against rot – of great importance with wooden ships and increasingly to railways and telegraphs. There were however other uses as a substitute for Stockholm tar, as for example in rope making but there were active investigations into new uses, as for road surfacing.
Tar made
from wood was a staple of maritime manufactures from at least the middle ages.
In the northern parts of Scandinavia, small land owners produced wood tar as a
cash crop. This came mainly from Sweden
but there were also producers in Finland and Russia – Archangel Tar was a
‘variety. In 1648, the NorrlSndska TjSrkompaniet (The Wood Tar Company of North
Sweden) was set ip and pine tar trading became concentrated on Stockholm. As Britain began to colonise North America so
these areas were encouraged to produce pine tar and pitch, for shipment to
England. England was then cut off from its Scandinavian supplies by Russia's
invasion of Sweden-Finland and by 1725 four fifths of the tar and pitch used in
England – primarily in the dockyards and by shipbuilders - came from the
American colonies until the split with America in 1776, when England was again
forced to trade with the Dutch for Scandinavian products.[1]
Supplies from the Baltic were under
increasing pressure during the Napoleonic wars and it was important to find a
supply of tar from a source that was not under threat. Coal, or 'mineral', tar seemed to be the
answer.
There were various experimenters but the most successful was in
Scotland, and was Archibald, the ninth Earl of Dundonald.[2] As an ex-naval officer, he knew that there
was a demand for tar in shipbuilding,[3]
where it was used in rope making but increasingly in the outside fabric of a
wooden ship to proof against rot and worm. Tar and pitch were, he said,
'essential to a maritime power'.[4]
In 1781 he patented a process making tar from coal but his sales to the navy
were not successful,[5]
nor were ship's repairers grateful for his work which threatened to put them out
of business.[6] From around 1810 designers of warships
considered the use of a coating of coal tar on ships for sophisticated
structural reasons - to turn them into a 'solid body'.[7]
Tar works were set up in Scotland, in the Midlands and eventually in east
London but it was needed in the Royal Dockyards in Deptford and Woolwich and it
also meant that ‘mineral tar’ was not an unfamiliar product.
The earliest gas companies in London were set up with a remit to manufacture tar and sell it profitably. They knew that the navy wanted a means to protect ships from rot. In 1816 the earliest company, the Chartered based in Westminster, recruited a Mr. Dalton who had worked at Blackwall Yard – directly opposite Greenwich across the river. He was an expert on the use of coal tar in shipbuilding working as a caulker. [8] He wrote, on behalf of the gas company about tar in connection with caulking, to the Navy Board - the civilian body in charge of naval purchasing. The Board agreed to let him undertake 'experiments' - in fact demonstrations - at Deptford Dockyard. Dalton pointed out to them possible savings of '8/6d. per barrel in dipping paper beside oil and fuel'. He followed by suggesting that they might like to take 100 tons 'for use on ships' bottoms'. He later suggested tar for rope making and offered to demonstrate by making up some rope using Chartered's tar. [9]
Dalton's persistence gained some success. In September 1817 the Navy Board officers discussed with him the purchase of coal tar 'in barrels similar to those in which tar is imported from Russia and Sweden. It was, however, nearly a year before they placed an actual order for '10,000 tons of coal tar at Woolwich'.[10]
The relationship with the Navy Board continued. By 1819 naval shipbuilders were using coal tar as 'the best prevention against dry rot ... and every ship is now completely saturated with it by means of a forcing pump'. By 1824 thirteen battleships had been injected but then the scheme was changed and linseed oil was used instead. The reason given by the Navy was the unacceptable smell of coal tar.[11]
After repeated failures in getting orders
for tar from the Navy, the Company Secretary took over the job from Dalton of
replying to tenders. He succeeded in getting an order from the Navy Board
Commissioners for 'mineral tar fit for making cordage. But within three months
of their first sale for rope making it appears that the rope makers of Woolwich
Dockyard did not like the smell of coal tar. G.Smith of the Navy Office wrote to say that
'the use of mineral tar in the manufacture of cordage is having a pernicious
effect on the workmen'. He 'desired the Superintendent at Poplar to remove what
is left at the ropeyard at Woolwich'. The
Gas Company quickly sent the Board '37,000 galls of tar that we feel confident
will not be injurious to the health of the their workmen'. However the contract
was cancelled. [12]
[1] Mystic Seaport. Web site
[2] Archibald is the father of Thomas Cochrane, the 10th Earl, who will feature elsewhere in these pages both as a naval hero but more importantly as an inventor of various steam engines and other devices.
[3] Hautala, Svomalisen Tiedeakatemian Toimitskia", 1970
[4] Lloyd, Lord Cochrane
[5] A.Cochrane, Account of Coal Tar, Edinburgh, 1784.
[6] The need was for tar to proof against damage by teredo worm – but ship repairers were kept in work by this damage
[7] Lambert The last sailing battlefleet
[8] Parliamentary Enquiry into Chartered Co. Bill 1809
[9] GLCC DM, 11th April 1817 et seq
[10] GLCC DM
[11] Lambert
[12] GLCC
No comments:
Post a Comment