Regarding the location of the 70in engine at Trewavas, (going off the original subject somewhat), Ken Brown was adamant that this was located inland and that the existing more westerly engine house must have been for a smaller engine than the 45in. However having done a very detailed search through all archive evidence and also a great deal of fieldwork on the site, my conclusion was that the western surviving house was for the 70in. Detailed measurements of this show it is in fact substantially larger than that for the 45in. Part of the argument for this was the location of the inclined shaft which was tied in with the workings pumped from the 70in, which I thought might have started from the second shaft close to the western engine shaft, & went off at an incline below sea level. The real evidence which none seemed to have been able to relocate was a section at the CRO referred to by AK Hamilton Jenkin. After many years tying to find this both by
myself & CRO staff this has now been located, & is shows surface features in great detail & the South Lode workings in great detail, including the Inclined Shaft located just as I had suggested. It shows the 45in engine house but not that on the western (lower) engine shaft, indicating the latter was built after the section had been drawn, although the underground workings had been updated. This all goes to support my view Ken was mistaken on this subject.
Eventually hope to write up the results of our research, only at the moment waiting to trace some documentation the National Trust reports are held somewhere privately possibly in Porthleven.
On Tuesday, 29 April 2014, 23:34, Paul Smith <[log in to unmask]> wrote:
Thanks Andy, I now have your article about the Snailbeach machinery, and find your argument compelling about the year of installation of the 60 inch engine, it makes a lot of sense, I am hoping to visit Snailbeach again in May/June time, equipped with measuring instruments, I now have the information I need to estimate the strokes from measurements of the engine house cylinder loading and balance bob slot. But the 10ft indoor, 9ft outdoor stroke seems most likely, as the pumps were in the main shaft 9ft pump stroke is probably correct as stated, it is the engine stroke which seems to be recorded wrongly, 6ft stroke for a 60 inch engine seems very small. The 10ft stroke mentioned in the PDMHS journal is probably the correct measurement.
Measuring the approx half length of the beam seems the best way to prove this. The indoor half of the beam would have to be very short for a 6 foot engine stroke! (Only about 10ft from beam from centre gudgeon to the cylinder end gudgeon). Whereas 9ft stroke equates to approx 15ft from centre to pump rod gudgeon. Even allowing for different positions of the centre gudgeon on the bob wall, the measurements of the engine house should be accurate enough to estimate both engine and pump strokes. Certainly to prove which stroke is the longer, engine or pump.
It would be good to know who manufactured this engine, but by the sound of it the records of this time are very incomplete.
Anyway thanks for a very interesting and informative article on Snailbeach.
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