SY6768 : A sighting of the tide race off Portland Bill

taken 1 year ago, near to Southwell, Dorset, Great Britain

A sighting of the tide race off Portland Bill
A sighting of the tide race off Portland Bill
The tide in the English Channel runs generally east or west. The Isle of Portland deflects the tidal stream southwards. Off Portland Bill the south-flowing stream meets an east- or west-flowing stream, creating turbulence – a tide race – which is made worse by a dramatic reduction in depth off the Bill and the action of wind. Sailors are advised to avoid the race and vast eddies, either by sailing several miles south of it or by taking the inshore passage, a narrow strip of calmer water close to the shore SY6768 : Taking the inshore passage, Portland Bill. The tide race is also seen in SY6768 : The Red Crane .
The tide race is shown in an aerial photo in the University of Southampton's Geological Field Guide to Portland Bill: LinkExternal link in LinkExternal link The main location of the race would appear to be SY6867.
It featured in Yachting Monthly, 9 December 2015: "It has a fearsome reputation. Tom Cunliffe, author of the Shell Channel Pilot, describes this place as ‘the most dangerous extended area of broken water in the English Channel. Quite substantial vessels drawn into it have been known to disappear without trace.’ There is a ferocious tidal stream off the Bill, reaching seven knots at springs. This creates a race with heavy overfalls, particularly in wind-against-tide conditions, which moves menacingly around the Bill as the state of tide changes. Overfalls can extend up to seven miles offshore." Read more at LinkExternal link
Overfall: "A turbulent stretch of open water caused by a strong current or tide over a submarine ridge, or by a meeting of currents." Here, it may also mean a change in the height of the sea surface as the water lifts or drops in response to submarine topography.
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SY6768, 408 images   (more nearby )
Photographer
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Date Taken
Saturday, 16 September, 2017   (more nearby)
Submitted
Thursday, 13 September, 2018
Geographical Context
Coastal  Air, Sky, Weather  Estuary, Marine 
Place (from Tags)
Portland Bill 
Subject Location
OSGB36: geotagged! SY 6796 6802 [10m precision]
WGS84: 50:30.6653N 2:27.1932W
Camera Location
OSGB36: geotagged! SY 6779 6842
View Direction
South-southeast (about 157 degrees)
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Other Tags
Isle of Portland  Tide Race 

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Image Type (about): geograph 
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