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Saturday 25 February 2012


I wrote recently about the character-forming influence over my 3x great uncle Thomas Richard Guppy, a civil engineer, by his mother the inventor Sarah Beach Guppy. I was being a little disingenuous in not giving Thomas’s father some credit too.

Samuel Guppy married Sarah in the port of Bristol in 1795, and Thomas was born there two years later. Sarah’s first patent, for a better system for building the pilings for suspension bridges, was granted in 1811 – the same year this penny token was issued by the Patent Sheathing Nail Manufactory of Bristol.

Penny token of the Patent Sheathing Nail Manufactory, Bristol

The manufactory was owned by Samuel Guppy. In 1796 Samuel invented and patented a labour-saving machine for “cutting, heading and finishing nails” to which he added several patented improvements in 1804. His great innovation was the invention of a barbed copper nail for fixing copper sheathing to the wooden hulls of ships. Although a mere nail may not seem much of a contribution to marine engineering now, it was at the time such an important development that the British Government bought the patent for it from Guppy for the vast sum of £40,000 – about £3,000,000 at 2012 prices.

Wooden ships suffered greatly from wear and tear. The hulls were vulnerable to shipworm and seaweed infestations which affected both the structure and the handling of the vessels. Traditionally hulls were coated with oil, brimstone or tar to resist these perils. Early attempts at sheathing the hulls with lead or replaceable wooden skins met with partial success. From the mid-18th century the Royal Navy began experimenting with sheets of copper.

Halfpenny token of the Patent Sheathing Nail Manufactory, Bristol

Copper was effective, and the corrosive electrolytic reaction of the copper bolts used to attach it with the iron bolts of the hull’s internal construction was addressed by using alloys. By 1780 Britain was at war with America, France, Spain and Holland; the supremacy of the nation’s navy was essential, and the order was given to sheath the entire fleet. By the end of the war in 1783 the hulls of 393 vessels had been clad. Over the following three years, as problems with corrosion recurred, the decision was taken to re-bolt every single hull with copper bolts. The cost of all this was high – copper sheathing was up to six times more expensive than wood. But with the nation’s fleet and supremacy at sea at stake, it becomes obvious that the government thought the price of Mr Guppy’s patent pure copper sheathing nails a price worth paying.

Merchant ship owners began to adopt the practice, although it was generally an expensive option applied only to the best ships by owners wealthy and farsighted enough to maintain their fleets. Copper-sheathed vessels attracted lower insurance premiums from Lloyds and a new expression entered the language for an investment with a safe, dependable return – such ventures were described as copper-bottomed.

Farthing token of the Patent Sheathing Nail Manufactory, Bristol

Samuel’s company traded at 34 Queen Square Bristol, Grove Avenue Bristol, and 22 Dowgate Hill London, both addresses where the farthing, halfpenny and penny tokens he issued could be redeemed for coin of the realm. I’m not sure why Samuel needed to mint them. The rapid expansion of the economy caused by the industrial revolution at the end of the 18th century caused a severe currency shortage, which some industrialists overcame by paying their employees in their own currency tokens; but the building of a new Royal Mint in London was complete by 1809, two years before the issue of these coins.

After Samuel’s death, his wife Sarah’s last patent, in 1841, continued the family’s contribution to the science of wooden ship-building, with a device for the better caulking of wooden hulls. But by then, events in Bristol had already been set in motion which would render the wooden ship obsolete. In 1837 a family friend, Isambard Kingdom Brunel, launched his wooden-hulled SS Great Western, built at Bristol with financial and engineering backing from Samuel and Sarah’s eldest son Thomas. The success of that ship led directly to the construction of the iron-hulled SS Great Eastern in 1858, at that time far and away the largest vessel ever built. In their own ways, Samuel, Sarah and Thomas Guppy could all take some credit!

Since posting this, I've been told by a friend that when George Keats, the brother of the poet, emigrated to America in 1818, the ship he sailed on was advertised as being "copper bottom'd and copper-fasten'd." That's Guppy's doing!

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