Porthtowan is one of those locations that can only be in Cornwall. The idyllic blue mix of Atlantic surf, golden beaches and heather topped cliffs are punctuated by the scree of mine waste tips pouring down from long disused mine shafts. Where there are now holiday makers and second homes, there was once miners and engine houses; where now is heard the sound is now of playing children the hammering of the Cornish stamps once dominated.
On a day, sometime in 1828 a young William West was working on one of the engines that stood on here at Great Towan mine. It was no ordinary engine, for this was one of Samuel Groses’s 80″record breaking steam engines at Druce’s and Wilson’s shafts. Groses’s understanding of thermal efficiency had been pushing the performance of his engines up and up. He was the star of the Cornish engineers of the time, his engines were dominating the performance league tables, and now he was determined to increase his lead further.
William West on that fateful day was also determined, he had an idea that, if successful, would move steam engine efficiency along in another leap. If successful, it would also move his own career in another leap. And so, when Captain Grose away, the young west, the un-schooled farmer’s son born on Dolcoath mine, made a bold request of Captain Vivian, could he experiment with Grose’s precious engine? Captain Vivian in what must have been a great act of faith, agreed.
OS 1884 (survey 1881) Reproduced with the permission of the National Library of Scotland.
His plan was simple, and one that was an extension of the concepts proven so successful by Grose. Captain Samuel Grose and made huge advances by insulating the huge cylinder of the steam engine. This insulation kept the precious heat energy where it was needed, in the cylinder. West took the idea further, right back to the Cornish Boiler where the high pressure steam was produced.
Ordnance Survey 2016 Contains OS data © Crown copyright published under OGL
On that day the boiler and pipework had been lagged with sawdust. On that day, on the hill slopes above Porthtowan another advance in steam engine technology was made. More water was raised for every bushel of coal fed into the boiler because less heat was wasted heating the air above Cornwall, and more heat went into producing the high pressure steam demanded by the engine.
West’s idea worked, and Grose on his return was impressed. He adopted West’s improvement, and was rewarded with the engine achieving a new record of 87 million duty. A result that Thomas Lean described as,
“Began, as it were, a new era in duty of the steam engine.”
But there was a flaw in West’s plan. A simple basic flaw, with disastrous consequences. Of all materials to encase a hot, fire filled, boiler with sawdust should not have been a first choice. The result was predictable, the sawdust caught fire, along with the roof and woodwork of the engine house. But once the smoldering wood and been put out, the boiler was re-lagged, the lesson had been learnt, this time ash or burnt earth was used.
Grose gained the accolade of his achievements at Porthtowan, and West went on to make his own name.