Portland Harbour Phoenix Caissons

Mulberry Harbours are a little known detail that made D-Day a reality. Amid the stories of brave soldiers storming the beaches to take Europe back from the clutches of the Nazis, one very important question needed to be answered: How do you keep a massive overseas invasion force fueled and supplied without a port to dock ships in?

Simple: Build your own dock.

Mulberry Harbour was a massive operation to build giant ship harbours made completely out of steel and concrete. It would have to unload 12,000 tons of cargo a day to keep the invasion force fueled until a proper port could be occupied and utilized to keep the invasion force going.

The day after D-Day, massive sections of the Mulberry Harbours were floated onto and just off the shores of Normandy and assembled. The harbours included massive concrete blocks called Phoenix Caissons and their purpose was to shield the ports from poor weather and enemy fire. The Caissons had the ability to be sunk and re-floated (hence the name Phoenix, as they could rise again).

The Mulberry Harbours went on to outperform their designed purpose and many parts were left off the coasts of France and England, while others were salvaged and given new purpose.

Ten Phoenixes were raised and floated to Portland in 1946, where they acted as wind-breakers for the port until 1953, when eight were sent to the Netherlands. While some Phoenixes in the Netherlands have now become museum attractions, the two left in Portland have remained in place, still acting as windbreakers.

Not only are they functional, but they act as a memorial to the massive engineering feat of the Mulberry Harbour and the war as a whole. The local WWII and D-Day museum tells more about the Harbours' story and the mannequins on top of the Mulberry Harbours stand as representations of British Troops, American GIs, and dock workers who made the operation possible.

Without the context of knowing how these leviathans of concrete played an important role during one of the most pivotal days in history, it would be very easy to overlook these structures of great historical importance.