Crucial D-Day harbour revealed in stunning 3D thanks to hi-tech survey

Stunning 3D images have been produced of the artificial harbour built to support the invasion of Normandy 70 years ago. The UK Hydrographic Office - which provides Royal Navy warships with charts to conduct their daily global missions - has carried out the most detailed survey yet of the 'Mulberry harbour' at Arromanches.

This is part of the greatest temporary harbour ever built - Mulberry B, the vital man-made haven created off Arromanches in France to support the Normandy landings in June 1944.

The remains of the artificial harbour were scanned on behalf of the UK Hydrographic Office - the people who provide the Royal Navy (and many of the world's seafarers) with charts.

To test new methods and train some staff, the UKHO teamed up with commercial survey firm Netsurvey to conduct the first detailed survey of the Mulberry for the first time in nearly 20 years.

Back in WW2 the harbour was used for nearly ten months by the Allied forces as they pushed into France, liberating it from the Nazi yoke, and then into the heart of Hitler's Germany.

Mulberry B - also known as Port Winston - was one of two such artificial harbours built; the first, to the west off Omaha Beach, was wrecked by a Channel storm at the end of June.

B survived - and thanks to it 500,000 vehicles, four million tonnes of supplies and more than two and quarter million men were put ashore.

The images show the underwater remains, lying at a depth of about five metres - and previously hidden from all but divers

Chris Howlett, Head of the Hydrographic Office's Seabed Data Centre

The harbours were constructed in the UK and then assembled off the French coast, with work beginning just three days after D-Day.

Some of Mulberry B can be seen on the beach at Arromanches, and rising out of the Channel - but much more is beneath the waterline.

And whilst the last survey of the huge structure by French hydrographers back in 1993-94 ensures the waters off Arromanches are safe for navigational purposes, the work carried out by the UKHO is intended to help archaeologists.

The resulting 3D map of most of the harbour - the eastern end is in shallow water and festooned with floats for crab pots, making it too difficult to reach - will allow experts to assess the rate of deterioration of what is left of Mulberry.

D-Day Harbour 3D Images

Looking down on a set of caissons located in the western breakwater

The surveyors spent two weeks aboard the small boat Xplorer, fitted with a scanning laser and multibeam sonar to precisely record the above and below-water remains of Mulberry B, while the craft towed a magnetometer to see if there was any debris buried.

The UKHO team are delighted with the results - its surveyors gained the experience they required and most of Mulberry B was very accurately recorded.

"It's one of the most impressive and important examples of military engineering ever - and a triumph of British ingenuity and engineering skill," said Chris Howlett's, head of the hydrographic office's seabed data centre.

"The images show the underwater remains, lying at a depth of about five metres - and previously hidden from all but divers."

The Royal Navy is commemorating the defeat of the submarine and the 70th anniversary of victory in the Battle of the Atlantic this spring. Visit Battle of the Atlantic 70th Anniversary for the latest news, details of events, history of the conflict and first-hand accounts from the men who were there.

If you want to explore the remains of the harbour, you can order a DVD containing the survey data and other images from the UKHO.

The hydrographic office is making this DVD available for free - but requires a donation to be made to its chosen charity for 2013, Freewheelers, a group which provides a free out-of-hours motorcycle courier service to hospitals in the South West of England.

To obtain the DVD send a stamped addressed envelope (make sure it is large enough to hold a DVD) and a cheque for at least £5 made payable to 'UKHO Charity' to:

Michelle Blagdon
Admiralty Way

UK Hydrographic Office