Page 3 – Supporting acts

Fooling the enemy and supplying the landings 

It was not just the landings on Normandy that required months of planning. Alongside the real landing plans, a complicated fake plan was developed to fool the Germans. Landed troops needed food, equipment and fuel, so helping to meet these needs, two massive engineering projects were conceived and carried out.

Operation Fortitude

Operation Fortitude was designed to make the Germans think the Allies would land in Pas de Calais as expected.

Vehicles and dummy landing craft moved to eastern England. From there fake radio messages suggested assault divisions were massing. An invasion fleet was simulated. On the night before D-Day small flotillas of motor boats headed towards Pas de Calais. They were fitted with radar equipment that made them seem much larger on enemy screens.

This fake flotilla was joined by Royal Air Force planes that dropped bundles of window (reflective aluminium strips). On German radar, the window created the impression of hundreds of ships headed for the decoy area, drawing attention from the real landing sites.

Operation Fortitude was a success. When the real invasion happened, the Germans believed it was yet another diversion and held back their reserve troops for several critical days.


Pipe line under the ocean (PLUTO) was built to supply fuel to troops in France. Specially designed pipes were coiled around drums and run out from cable-laying ships. The first PLUTO ran along the bed of the English Channel over the 100 kilometres from the Isle of Wight to Cherbourg. Other pipes were laid later in the campaign, and these delivered up to 18,000 litres of fuel a day.

Mulberry harbours

Mulberry harbours were a complex system of temporary floating quays. They provided artificial harbours on the coast of Normandy until ports were in Allied hands. The huge concrete and steel structures were built in rivers and inlets around Britain. It took 20,000 workers just seven months to finish the job. In the wake of the armada, the Mulberries were towed across the English Channel to form breakwaters for sheltering and unloading ships.

How to cite this page

'Supporting acts', URL: https://nzhistory.govt.nz/war/d-day/supporting-acts, (Ministry for Culture and Heritage), updated 20-Dec-2012