The success of Overlord was in part dependent on detailed
topographical map information about the beaches and coastal towns along the French coast. British experience of Galipolli in the First World War
, with the loss of 100,000 dead or wounded troops, meant that detail was necessary to ensure the invading army did not get stuck on the beach.
Aerial photographs helped identify likely locations but, to obtain more detailed views, the Government asked the
picture postcards
of unspecified coastal areas of France.
However, as it was known that the beaches were in parts underpinned by ancient forests which had turned into
peat bogs
before becoming submerged, much more detailed information on the target beaches and their approaches was required. Local conditions such as the composition of the beaches, hidden underwater banks, German defensive obstacles, depth of water, tidal conditions etc. would all be taken into account in the planning of the project.
Pilot operation
On
hydrographical survey craft, they moved closer to shore where Major Logan Scott-Bowden and Sgt Bruce Ogden-Smith swam to the beaches. Collecting samples at designated points, they were careful not to leave behind evidence of their visit, and returned to England the next morning.[1]
On 16 January 1944, X20 planned to spend four days off the French coast. Commanded by Lt K.R. Hudspeth DSC* RANVR and Sub. Lt. B. Enzer RNVR, with the COPP (Combined Ops Pilotage Party) comprising Lt. Cdr. Nigel Willmott DSO DSC RN, and the same divers, Major Scott-Bowden and Sergeant Ogden-Smith.
X25 X-class submarine, the type used
During the daytime,
condoms
.
The divers went ashore on two nights to survey the beaches at
benzedrine tablets) and the worsening weather caused Hudspeth to shorten the operation, returning to HMS Dolphin
The allies built two scale models of the landing beaches, one held by the
Cabinet War Rooms
.
At Cairnryan, just north of Stranraer, south west Scotland, a "life size" reproduction of the beaches was constructed. This allowed the planners to assess the effectiveness of the current landing techniques and the movement of men and machinery over the terrain.
