This image of kite surfers flying their kites at Calshot Spit in the Solent Southampton clearly shows the sand and gravel bars at Calshot that represent a real danger to shipping in their journey to and from the Port of Southampton. I believe that the concrete pontoon visible in the image was used by both commercial flying boats and later by the Royal Air force during World War 2. Image captured in June 2010 from the deck of a Red Funnel car ferry.