Thread: Building a Caisson for Mulberry Harbour

The figures of the construction workers give an indication of the size of these concrete caissons which formed the outer breakwater for each of the two Mulberries.

The large concrete boxes known as Phoenix, were built on the South coast of Britain, and launched sideways as shown in this film still. Many were sunk to conceal them from prying German air reconnaissance, before being refloated and towed across to Normandy for the two artificial harbours known as Mulberries.