The Mulberry Harbour (using the British spelling since it is located on a British invasion beach and that is the one used in all the literature on them) was an essential part of the plan to make the D-Day invasion successful. The Allied leaders knew that having a port to bring in supplies and men was necessary - that is why they originally tried to come into Europe at Calais - a city further north in France with it's own port, but the Germans were aware of the Allied need for a port and placed heavier protection around any existing port and that attack failed, so Winston Churchill decided that if he couldn't take a port, he'd make one instead (sounds a bit like the Grinch and reindeer, doesn't it??!!). He is quoted as having told his staff "They must float up and down with the tide. The anchor problem must be mastered………let me have the best solution worked out. Don’t argue the matter. The difficulties will argue for themselves."
The logistics of building this port, of which there were to be two - one at Omaha Beach and one at Gold Beach, were huge! Each harbour was to be made up of about 10 miles of flexible steel roadways with 33 jetties that would float on steel or concrete pontoons. The roadways were codenamed "whales" and the pontoons "beetles". The whales ended at huge pier heads that had legs that rested on the seabed. This whole structure was protected by a breakwater made from scuttled ships and 146 sunken Phoenix caissons (each one 230 feet long and 66 feet high and 49 feet wide) and floating breakwaters too. Materials required - 500,000 tons of concrete, 85,000 tons of ballast, and 105,000 tons of steel for one harbour. Construction of the pieces needed began long before D-Day, with people working in England having no idea what they were building. As each piece was finished, the Allies sunk them in rivers and other waters in England so the Germans would not be able to see them. Each piece was towed across the English Channel at just over 4 miles per hour when the day arrived! Both Mulberry Harbours started being constructed on June 6th as part of the invasion.
Unfortunately as we already know, the harbour at Omaha Beach was destroyed in the violent storm of June 19th, but it had certainly helped get things going before that happened. The harbour at Arromanches on Gold Beach remained functional for several months, landing over 500,000 tons of equipment by August - an amazing and logistical feat beyond measure!
Not much remains of the Mulberry Harbour - many of the caissons are still there and can be seen at low tide.
Alex, Amanda, Curt
Amanda takes a picture of the inside of a caisson while Alex, Curt, and Casey go around the corner of it.
Inside the caisson
This is how the road sections came over from England
Now you understand why Amanda is considering doing her project on the Mulberry Harbour - it was such a huge feat of engineering skill!