Constructed of various concrete caissons and pontoons, The Mulberry harbours were the innovation that made the whole Normandy campaign subsequent to the D-Day landings possible.Constructed of various concrete caissons and pontoons, The Mulberry harbours were the innovation that made the whole Normandy campaign subsequent to the D-Day landings possible.
The idea was that allied forces could be re-supplied through pre-fabricated harbours towed into place on the invasion beaches. This enabled the momentum of the attack to be maintained until major ports could be captured and cleared for allied use.
The Mulberry unit off Pagham is a Phoenix unit, a 60 metre long 6044 ton reinforced concrete caisson barge, designed to be towed into place and sunk to form a pier from which ships could be unloaded.
The various Mulberry structures were built at many waterside locations throughout the UK and stored along the south coast prior to the invasion. Strings of concrete and steel Mulberry units were then towed across the channel to build harbours at Arromanches for the British and at Omaha beach for the Americans. These were not just little harbours; the enclosed area of each was equivalent to the harbour at Dover.
By the end of October 1944 over 600,000 tons of supplies and 40,000 vehicles had been landed at Arromanches. The American Mulberry was less successful, being badly damaged in a storm, possibly because the units had been wrongly assembled and inadequately secured.
Remnants of the Arromanches Mulberry harbour can still be seen and even dived from liveaboards touring the Normandy coastline.
The Pagham Mulberry was one of many stored in the area by the simple method of flooding them until they rested on the seabed, then pumping the ballast tanks out to re-float them for the invasion. When the unit was refloated the tugs were not ready and it had to be sunk again. In the process it had swung in the tide and broke its back as it settled across its own previous scour in the seabed.
During my dive I descended into one of the biggest shoals of pouting I have ever seen. Thousands and thousands of them swirling in the current. I was wearing my Dräger and with hardly any bubbles I could just hang out and be at one with the fish. They soon got used to me.
The reinforced concrete structure is now very broken up with rusty sharp ends of reinforcing rods projecting at all angles, so care has to be taken to avoid impalement. The concrete walls and piles of rubble on an otherwise flat gravel seabed forms an oasis for marine life. Apart from the huge shoal of pouting, there were slightly less numerous pollack beneath the overhanging bow at the north end of the wreck and cracks and holes provided homes for conger eels, lobsters, crabs and squat lobsters.
Further round, the more broken southern end and upper surfaces of the wreckage formed kelp shaded glades through which sea bass and ballan wrasse meandered while pecking at the general carpet of smaller weeds and animals. On a warm July day with bright sunshine, shallow water and 10-metre visibility, the overall effect was positively tropical.