Footnote to cruising the Scillies: piloting there is a reminder of the importance of proper Admiralty charts, because they show the age of the surveys on which they are based, unlike any of the proprietary ‘vector’ charts available on chartplotters.
The Scillies is a mixed area from this point of view. Some of the surveys of the area were last done in 1860 – 1904 by lead line, probably from boats carried on naval survey ships and rowed up and down in straight lines quite a long way apart, so rocks could easily be missed. Other parts of the islands were surveyed at a range of different dates in the 20th century. Continue reading “Is your chart relying on an 1860 survey?”