Dunnose is a cape on the

Isle of Wight The Isle of Wight ( ) is a Counties of England, county in the English Channel, off the coast of Hampshire, from which it is separated by the Solent. It is the List of islands of England#Largest islands, largest and List of islands of England#Mo ...

in the English Channel. The headland is visible from well out to sea, and is used in navigation. It has twice been used as the base point for a triangulation of Great Britain. The line of accurately surveyed points running north from Dunnose to Clifton in

Yorkshire Yorkshire ( ; abbreviated Yorks), formally known as the County of York, is a historic county in northern England and by far the largest in the United Kingdom. Because of its large area in comparison with other English counties, functions have ...

provide the basis for triangulation to determine the positions of all other locations in Britain.

History

German

U-boat U-boats were naval submarines operated by Germany, particularly in the First and Second World Wars. Although at times they were efficient fleet weapons against enemy naval warships, they were most effectively used in an economic warfare ro ...

SM UB-81 sank off the coast of Dunnose in December 1917.

Location

Dunnose Point lies to the east of

Ventnor Ventnor () is a seaside resort and civil parish established in the Victorian era on the southeast coast of the Isle of Wight, England, from Newport. It is situated south of St Boniface Down, and built on steep slopes leading down to the sea. ...

, and can be reached via the A3055. It is said to be haunted by HMS ''Eurydice'', which sank off the point on 24 March 1878 with the loss of 300 people. The bay between Dunnose and St. Catherine's Point to the southeast has a rocky bottom and can be hazardous, since the charts may not show all the submerged rocks.

Survey point

Around 1800 Dunnose was taken as a base point for a triangulation of Great Britain, in which Captain

William Mudge William Mudge (1762–1820) was an English artillery officer and surveyor, born in Plymouth, an important figure in the work of the Ordnance Survey. Life William Mudge was a son of Dr. John Mudge of Plymouth, by his second wife, and grandson o ...

measured a section of the meridional arc running up into Yorkshire. The triangulation was conducted in 1801 and 1802. The positions of twenty three points between Dunnose and Beacon Hill, Clifton, near Doncaster, were determined, and the closest possible measurements were made of the distances between the points and the direction from one point to another. Doubts were cast on the accuracy of the measurements in 1812, when Joseph Rodriguez pointed out that, if they were accurate, the length of a degree of longitude did not vary with latitude as it should if the earth were flattened at the poles. The

Retriangulation of Great Britain __NOTOC__ The retriangulation of Great Britain was a triangulation project carried out between 1935 and 1962 that sought to improve the accuracy of maps made of Great Britain. Data gathered from the retriangulation replaced data gathered during ...

that began in 1935 again took Dunnose as a base point. Dunnose also was the origin (meridian) of the 6 inch and 1:2500 Ordnance Survey maps for the central group of English counties: they were Derbyshire, Nottinghamshire, Lincolnshire, Staffordshire, Warwickshire, Worcestershire, Leicestershire, Rutlandshire, Northamptonshire, Gloucestershire, Oxfordshire, Buckinghamshire, Wiltshire, Berkshire, Hampshire and the Isle of Wight.https://www.charlesclosesociety.org/files/153Meridians.pdf

Notes and references

Notes Citations Sources * * * * * * {{refend Headlands of the Isle of Wight