A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Sumner and the Smalls lighthouse.
From: George Huxtable
Date: 2006 Mar 3, 19:40 -0000
From: George Huxtable
Date: 2006 Mar 3, 19:40 -0000
Bill asked, in a thread labelled "Simple celestial navigation in 1897"- | Back to Sumner, I eagerly await the results of George's inquiries into | Small's/Smalls (and other?) "migrating" lighthouse(s). It was clearly IMHO | within the abilities of civil engineers to erect such a structure on a | submerged shoal or foundation circa Smalls # 2. Is relocation the case, or | were there measurement problems? ================ Response from George- I'm still "on the case", investigating that matter. The mystery deepens, rather. I had expected a definitive answer "within a few days" from the lighthouse authority for those waters, Trinity House, as to the position of the predecessor to the present Smalls light, and where exactly that would have been in Sumner's time (1837). No response so far, but chasing them up recently, I have found that the lady who promised thus is on annual leave, back on Monday. So Bill will have to wait 'til then. The Bodleian library didn't start to acquire charts until the 1880s, but I visited their map room the other day, and they dug out for me "Cary's improved map of England and Wales", published 1832. This is a large-format atlas comprising county maps bound together, at 2 miles to the inch. Map 22 is of Pembrokeshire, extending westwards into St George's Channel, with an individual date of 1829. Although it shows lots of navigational information, including lights, soundings, and tidal streams, with scales of lat and long, it is basically a land-map, so would not perhaps carry the authority that a proper sea-chart might hope to claim. It was reasonably easy to measure off the positions of the Smalls light as given on that map to a tenth of a mile or so, to be N 51 deg 43.3', W 5deg, 38.8' And as drawn, it appeared to be sitting on top of the always-above-water Smalls rock. It was shown surrounded by drying rocks and shoal patches to about half-a-mile away. Outside that area, it's deep water; no chance of planting a lighthouse there. My guess is that both lighthouses, the old one that Sumner saw in 1837, and the new one of 1858, were in fact planted on the same rock, for which we have considerable divergence of position. Frank had written- "Here's some historical positional info for Small's/Smalls Rock lighthouse: I checked Bowditch 1826, 1842, 1849 and the position listed in these editions is 51d 45'N 5d 36'W. That's very likely the position known to Sumner. In the 1868 edition the position is about three miles away: 51d 43'N 5d 40'W. In the 1883 edition, which is when the US Navy took over and substantially re-wrote the book, the position is the same but more precise: 51d 43' 14"N 5d 40' 9"W. BTW, in all of these it's listed as "Small's" (possessive). In the 1918 edition of Bowditch, the position for "Smalls Rocks: lighthouse" (no longer possessive) is listed as 51d 43' 15"N 5d 40' 15"W. According to various web sites, the first Smalls Rocks light was built in 1773 and stood until 1858. It consisted of an octagonal cabin standing on nine massive oak posts. A new lighthouse was built from 1859-1861. It still stands ..." The best estimate I can make of Sumner's position for Smalls light, as he drew it on his chart in plate III, is N 51deg 48.4', W 5 deg 37.5', which is several miles North of any of those quoted positions for the lighthouse. Its real position will have been sufficiently far South of his plotted "Sumner line" that he would have had little chance of spotting it in the "thick weather" he describes. So was Sumner guilty of tinkering with the position of Smalls light, to make a better story? The evidence, so far, seems to point that way. It will become more definite, one way or the other, if and when Trinity House responds. ======================== I think it was Frank who wrote- |>"...With all the talk recently on Sumner's method, I think it's worth | > remembering that Sumner's lines were considered a somewhat exotic technique, | > one that might never be used in months at sea. Celestial lines of position | > didn't catch on universally until almost a century after Sumner published. | > And why that was the case is still a fascinating question..." To me, that's one of those sweeping statements, that cries out for a bit of backup evidence. There is much evidence to the contrary. In his "Wrinkles in practical navigation" (1881), Lecky, a practical navigator if ever there was one, and no academic, states that his chapters XI, on Sumner Lines, and XII, on Double Altitudes, are the most important in the book. He tells us that within a year of Sumner's publication, an order was given to supply a copy to every ship in the US Navy! So I wonder whether that statement is based on a biased sample of navigationally backward or ultra-conservative mariners; such as, perhaps, American whaling vessels. | George. contact George Huxtable at firstname.lastname@example.org or at +44 1865 820222 (from UK, 01865 820222) or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.