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Inshore End of the Mulberry Harbour, Arromanches

Inshore End of the Mulberry Harbour, Arromanches

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Inshore End of the Mulberry Harbour, Arromanches

Here we see the inshore end of one of the piers on the artificial Mulberry Harbour built at Arromaches after the D-Day landings. The vast fleet that supported the invasion can be seen in the background.

Mulberry Harbour

My father, Herbert Geoffrey Hall - Geoff Hall — was born in Macclesfield, Cheshire, in 1911, and died in retirement in North Wales in 2002, aged 90. During the Second World War he served in the Merchant Navy. He kept a diary of his experiences from which he later prepared accounts of some of the more memorable and important of these. This is his account of his involvement with the Mulberry harbour project.

On the 13th August 1944 we went across to the artificial harbour at Arromanches, towing a huge drum from which some miles of PLUTO (pipe line under the ocean) was being unwound to lie on the sea bed. I think about 5 pipes were laid altogether, about 120 miles long, but as alternative means of getting petrol supplies became available they were not much used.
In Arromanches it was quite remarkable where once there had been an open beach now there were deep-water quays (whales) joined to the beach by floating causeways along which flowed a never-ending stream of 3-ton trucks. An outer breakwater had been constructed by sinking no fewer than 16 old ships on one side, and a row of huge concrete blocks, which had been sunk and filled with sand, around the rest. Suitable openings had been left so that big ships could move in and out as necessary. All this and much more had been towed over from England in the early days.
There was tremendous activity, even though the war had moved away from this beachhead. As usual, no one seemed to know why we were there or what they wanted us to do, so we tied up to one of the sunken ships the Allenbank, an old friend of mine as she had been an anti-aircraft vessel on Convoy PQ 16 to Russia. For some days we did all sorts of odd jobs and there developed a pattern of air-raid warnings each evening, when we could hear aircraft but not see anything. Raids in the daytime were more common with bombs dropped and we came to the conclusion that, perhaps, small was beautiful after all. Work after dark was difficult as the forced draught fan located in the engine room required so much air that we had to keep the door and skylights open and the strict black-out meant we could only have a very dim oil lamp below.
The harbour was surrounded by a large number of barrage balloons whose winches were stationed every few yards along the cliff edge. These were intended to deter low-flying aircraft from attacking from that direction. One night a tremendous thunderstorm developed very quickly and, although the soldiers in charge of the balloons did their best to get them down, no fewer than 40-odd were struck by lightning and destroyed. A most impressive sight, as one saw the lightning strike the gas bag which took fire and slowly crumpled and fell to earth, but at the instant of strike the wire cable from winch to balloon became incandescent and came down in a rain of molten metal. I don't wonder the troops were reluctant to approach the winches.
At this time it was customary for the laden cargo ships to anchor about 3 miles out and to come in on their own power as quay space became available, but one day a ship coming in suddenly blew up and sank, as a result of passing over an acoustic mine. Now it became apparent what was the purpose of the evening raids we had heard some days ago. Jerry had been dropping acoustic mines across the path of incoming ships. Another imponderable was that these mines could be set so that a number of ships could pass and then, the fifth, say, would trigger the explosion. So, it was then decreed that the big ships must anchor 10 miles out and on being summoned to the harbour, must shut down everything in the engine room, including the generators. We then went out, took them in tow on a long rope and set off to bring them in. In our case we set everything going full belt and then sat on the engine room skylights wearing our life jackets. There were three of us assigned to this work and two of us survived.
After a little while things quietened down as the war moved away from us. Fewer ships came here as it became possible to use the Channel ports of France. Most of the small craft disappeared and we were left as Salvage, Rescue and Fire boat of the harbour. This gave some opportunity to go ashore and three of us were having a look at Bayeux on the 23rd August, the day that Paris was liberated. We were rather surprised at the lack of emotion shown by the locals. A few handshakes, a few bits of bunting and flags. I think their feelings had been drained to the limit.
Requiring bunkers a few days later we discovered that we had to do the job ourselves, i.e. shovel some 30 tons of coal into buckets and tip it into our bunker hatch on a hot day. This, of course, was why we had a "V" on our identity cards, a pledge to do anything, anywhere, as required.
A full gale developing a little later, and we were sent to tow the Harpagos off the beach, but working in the dark in foul conditions we again got a rope round one of our propellers. This time we were able to clear the rope after much heaving and juggling with the gear. The gale continued and things started to break up in the harbour.
A fresh block ship - concrete caisson arrived, all 4,000 tons of it, and we had to assist to get it positioned and sunk where wanted. These things were hollow and once sunk were filled with sand by a dredger. The dredger than knocked a hole in her bow on some obstruction and we had to get our salvage pump to work to keep her afloat. All this took a couple of days, during which we had very little sleep as the salvage pump was mounted on the bulkhead between our accommodation and the engine room and the noise was horrific.
When we had any slack days I used to make oddments - copper tankards, fancy spoons and an engine big enough for Val to ride on, which passed the time effectively. Suddenly on 17th September we were told to tow a damaged mine-sweeper back to Portsmouth. This we did and then moved over to the Town Quay in Southampton. As we were to be there a few days I managed a quick run home. Very pleasant but not enhanced by the fact that I had to stand in the train nearly all the way back and so we returned to Arromanches.
By now the war had moved far inland and Jerry was too busy elsewhere to bother with what had now become an obsolete port. Port, did I say? The damage caused by stress of weather was becoming ever more evident and several sections were breaking up or becoming unusable. We had little to do but were treated each evening to the overflight of many of our aeroplanes and even watched the 1,000 bomber raid on Le Harvre from a distance of some 25 miles or so.
Not having enough to do the crew began to get bored and restive so we were pleased when John Martell, who was acting as Superintendent for the Company, arrived on the 3rd November with news that we were to hand over to the French next week. Of course, it didn't happen and we continued to do odd jobs whilst we waited.
Requiring bunkers once again we moved to a quay where coal was stored expecting to have to do the job ourselves. This time, however, a gang of German Prisoners were sent down and they set about the work with gusto. It was interesting to see this lot working hard and singing at the top of their voices. I asked one who spoke English why he was so happy. He explained 1) the War was nearly over 2) they were all alive and being prisoners could expect to remain so and 3) they were prisoners of the British and this was much better than being prisoners of the Russians or even the Americans.
Another item of interest was the revival of life on the French coast. The place had been devastated and I don't think our people at home realised just how deprived everybody was. Some French fishermen made their small boats seaworthy and set off to catch fish in the Channel. As there had been no fishing for some years stocks were good, but you can't keep warm on fish, so, on their way home in the early morning, they would come alongside us and barter a box of fresh fish for a bag of coal. Dover soles barely 6 hours out of the water provided some of the best fish I have ever tasted.
Arrived back in Southampton and I came to the end of another remarkable piece of history. The Mulberry Harbour in conception and achievement was almost certainly the biggest engineering feat ever accomplished. Its story has been fully written up in several books but to have played a small part in it was, to an Engineer, an extraordinary experience and although those in charge frequently seemed not to know what we had to do next, one could only conclude that the opposition must have been equally inefficient or was it simply a matter of wealth and manpower? These matters I will leave to those better qualified than I am. However, to summarise some facts about the Mulberry I quote the "Guide Heimdal" of 1980. 'To build required 45,000 men, of use for 80 days, landing about 7,000 tons per day. 60 ships scuttled, and over 200 concrete caissons built to form outer breakwater of 3.7 miles long. 33 whales led onto 10 miles of floating jetties. 164 tugs employed on the project which weighed in total 1.5 million tons. One can only admire those who could visualise so big a scheme and then have the courage to carry it out.'

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Inshore End of the Mulberry Harbour, Arromanches - History

To supplement supply from landing craft on the beach, the British invented and built a pre-fabricated harbor, which they towed into place and assembled on the coast of France. Two harbors were actually made, one at Arromanches for the British and another on Omaha Beach for the Americans. A storm largely destroyed the Omaha Beach harbor, but the one at Arromanches was repaired and continued to function into the autumn of 1944, even after a number of ports had been captured. Remains of the harbor are still visible, and there is a wonderful museum the town of Arromanches explaining it.

Design was begun in 1942 in reaction to the Dieppe Raid, when it became apparent that the Germans would keep French ports well defended. In addition, in the Mediterranean the Germans showed their willingness and skill at destroying ports before their capture. Winston Churchill was an eager proponent of the Mulberry Harbor concept. Despite Churchill's enthusiasm, final construction of the pre-fabricated components was a rush job in the spring of 1944. Assembly in Normandy began just a few days after D-Day.

Mulberry from Longues Battery

From Atop the cliffs to the west, you can make out the shape of the artificial port. A rectangular shaped area was protected by blockships and pre-fabricated caissons.

This is the view from just outside the museum. In the distance, you can see the remains of the caissons that protected the harbor. On the beach, you can see the remains of the floats of the pontoon bridges, which came ashore in this vicinity.

Behind the protection of these breakwaters (foreground), bridges on pontoon bridges were built out to piers where ships could be offloaded (center and background).

These are the large concrete structures floated, towed really, across the Channel, then flooded so they would sink and form a barrier to high waves. Unfortunately they were designed only for flooding, not for being pumped out, so they were immovable once sunk. They were also liable to being swamped, so later version had a steel top despite the wartime shortage of steel. Some of the caissons mounted anti-aircraft guns or barrage ballons. Although the Luftwaffe had sustained heavy losses by this point in the war, the Mulberry Harbor was an inviting target. In addition to here at Arromanches, casissons and blockships were used elsewhere to ease debarkment across beaches without the system of bridges and piers. Floating devices known as bombardons were also placed further out than the caissons in the hope of protecting the harbor, but they were generally considered to be a failure.

Also towed across the Channel were the bridges and pontoons. Maximum towing speed was just three knots.

The pontoons were anchored, stongly at Arromanches, not so strongly at Omaha Beach. The bridging sections were designed to be flexible to account for the waves, and they were cabled together.

This is one of the remaining bridging sections. The round surface that you can see at the corner is where they sat on the pontoon. The rounded surface allowed for the flex that was inevitable from waves and from vehicles passing.

Because of tides, a special floating piece was required at the end. There were two bridges out to the pier, one for empty traffic going to the pier, one for full traffic coming to the beachhead.

Most pontoons were made of concrete to conserve steel. Some pontoon sections, like the one at left, were more securely attached to the bottom. These steel pontoons were rigged to float up and down with the tides through poles that sat on the bottom. The middle bridge span you can see is different than the ones on either side. It is built to telescope, or expand and contract to account for tides and the movement of vehicles.

These are some of the remains of the pontoons.

There were seven platforms making up the piers. They could be connected with expandable bridges and rectangular floats.

This is a section designed for unloading LSTs, vehicles which would ordinarily beach themselves to debark directly onto the beach. On the Mulberry Harbor, a flating wedge was designed for the LST to beach itself and unload from its bow. In addition, the LST could be unloaded from its side, making for a much quicker operation. Two LSTs could be unloaded in less than an hour. And unlike a beached LST, one unloading at Mulberry would not have to wait many hours for the tide to allow them to leave, which could take six hours.

Like the pontoon bridge, the platforms of the piers were designed to move up and down with the tide on poles that rested on the bottom. This meant that the ships, the platforms, and the bridges were always at the same level, insuring that the harbor could be used around the clock.

Some platforms were used for unloading Liberty ships. Cranes were used. Too late, it was determined that conveyor belts might have been more efficient. The small vessel in the water is a DUKW, an amphibious truck. A surprising percentage of the cargo was transported to shore by DUKW.

Also part of the logistics effort was 'PLUTO', a pipeline under the Channel made of lead, rubber, and steel - designed to bring fuel to the Allied troops.

Despite the efficiency of the Mulberry Harbor, the majority of men and materiasl arriving in France were deposited the old fashioned way, on the beach. Because of this, and the failure of the Mulberry at Omaha Beach following the gale, some people question the wisdom and usefulness of the Mulberry Harbor. However, it did give the Allied command the confidence to make a landing away from a major port, in an areas which were much less well defended.

Story behind the Mulberry Harbour Blocks on Burnham-On-Sea beach

For lying here, partially buried in the sand, are the remains of 30 large concrete blocks which formed part some of the man-made Mulberry Harbours used to land troops and machinery in France.

The story behind these blocks is incredible. By 1944 the Germans had used their years in France to turn most of the English Channel ports into fortresses, so much so that there was no question of capturing them in an attack either from sea or air.

The Allied troops needed harbours in order to land their hundreds of thousands of troops and millions of tons of supplies which would be needed if Operation Overlord, the code-name given to D-Day, was to succeed.

The apparently ridiculous idea was mooted of using artificial harbours to land and support what was to be the world’s greatest invasion. Such was the scale of the operation that two harbours would be required, each the size of Dover itself.

The harbours, code-named ‘Mulberries’, would consist of 73 individual prefabricated concrete blocks which when assembled would make up the ports, breakwaters and pontoons where ships could tie-up and unload their precious cargoes.

Floating ramps would be used as roadways to allow the lorries to be driven directly on to the beaches. The component sections of the harbours would be built in ports throughout the UK and towed across the Channel for final assembly off the Normandy coast.

The most spectacular feature of the Mulberry project were the huge, hollow blocks of concrete – which can be seen on Burnham Beach.

Before being flooded, each block weighed between 1,500 and 6,000 tonnes. The largest ones measured sixty by seventeen metres, and were the height of a five-storey building.

In the early hours of D-Day June 6th 1944, an invasion fleet of more than 1,000 ships carrying 156,000 men headed towards the coast of Normandy, and the individual sections of the two Mulberry Harbours went with them.

Tugs towed the sections of concrete and steel pontoons which would make up the seven miles of piers and jetties. After assembly one harbour would support the American sector opposite Omaha, the other the British and Canadian beaches, opposite Arromanches.

In the first six days of the invasion the Allies managed to land a third of a million men on French soil.

Once the war was over, some of the blocks were left in place along the French coastline (and can still be seen today) while others were removed and dropped off around the coastlines of England to be used as sea defences.

The Mulberry Harbour

The Mulberry Harbour was built for D-Day in June 1944. The Mulberry Harbour’s purpose was to ease and speed up the unloading process so that Allied troops were supplied as they advanced across France after breaking out from Normandy. The success of D-Day could only be maintained if the advancing troops were supplied and more men landed. The Mulberry Harbour was one of the greatest engineering feats of World War Two.

Remnants of the Mulberry Harbour at Gold Beach

Support for the harbours came from on high – Winston Churchill.

“Piers for the use on beaches: 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 Mulberry Harbour was actually two artificial harbours, which were towed across the English Channel and put together off the coast of Normandy. One, known as Mulberry A, was constructed at Omaha Beach and the other, known as Mulberry B (though nicknamed ‘Port Winston’), was constructed off Arromanches at Gold Beach. Put together like a vast jigsaw puzzle, when both were fully operational, they were capable of moving 7,000 tons of vehicles and goods each day.

Each of the two artificial harbours was made up of about 6 miles of flexible steel roadways that floated on steel or concrete pontoons. The roadways were codenamed “Whales” and the pontoons “Beetles”. The ‘Whales’ ended at giant pier heads that had ‘legs’ that rested on the seabed. The whole structure was protected from the force of the sea by scuttled ships, sunken caissons and a line of floating breakwaters. The material requirements for any part of either Mulberry A or B were huge – 144,000 tons of concrete, 85,000 tons of ballast and 105,000 tons of steel.

The various parts of the Mulberry harbours were made around Britain in the greatest of secrecy. The many various parts were moved to Normandy immediately after June 6th – D-Day. By June 18th, both harbours were in use. They were meant to stay in use until the capture of Chebourg in the north of the Cotentin Peninsula.

However, a violent storm begun on June 19th. By June 22nd, the harbour serving the Americans at Omaha had been wrecked. Parts of it were salvaged to repair the British harbour at Gold which worked for 10 months. In that time this harbour landed 2.5 million men, 500,000 vehicles and 4 million tons of goods.

For all its apparent success, the idea of Mulberry did not have the support of everyone:


The Dieppe Raid of 1942 had shown that the Allies could not rely on being able to penetrate the Atlantic Wall to capture a port on the north French coast. The problem was that large ocean-going ships of the type needed to transport heavy and bulky cargoes and stores needed sufficient depth of water under their keels, together with dockside cranes, to off-load their cargo and this was not available except at the already heavily-defended French harbours. Thus, the Mulberries were created to provide the port facilities necessary to offload the thousands of men and vehicles, and tons of supplies necessary to sustain Operation Overlord and the Battle of Normandy. The harbours were made up of all the elements one would expect of any harbour: breakwater, piers, roadways etc.

Development [ edit | edit source ]

The actual proposer of the idea of the Mulberry harbour is disputed, but among those who are known to have proposed something along these lines is Hugh Iorys Hughes, a Welsh civil engineer who submitted initial plans on the idea to the War Office, Professor J. D. Bernal, and Vice-Admiral John Hughes-Hallett.

At a meeting following the Dieppe Raid, Hughes-Hallett declared that if a port could not be captured, then one should be taken across the Channel. This was met with derision at the time, but in a subsequent meeting with Winston Churchill, the Prime Minister declared that in 1917 ΐ] he had surmised a similar scenario using some German Islands and sinking old ships for a bridgehead for an invasion in World War I. The concept of Mulberry harbours began to take shape when Hughes-Hallett moved to be Naval Chief of Staff to the Overlord planners.

A trial of the three eventual competing designs for the cargo-handling jetties was set up, with tests of deployment at Garlieston, Wigtownshire. The designs were by Hugh Iorys Hughes who developed his "Hippo" piers and "Crocodile" bridge units on the Conwy Morfa, using 1,000 men to build the trial version the Hamilton "Swiss Roll" which consisted of a floating roadway made of waterproofed canvas stiffened with slats and tensioned by cables and a system of flexible bridging units supported on floating pontoons designed by Major Allan Beckett, Royal Engineers. The tests revealed various problems (the "Swiss Roll" would only take a maximum of a 7-ton truck in the Atlantic swell). However the final choice of design was determined by a storm during which the "Hippos" were undermined causing the "Crocodile" bridge spans to fail and the Swiss Roll was washed away Beckett's floating roadway (subsequently codenamed 'Whale') survived undamaged. Beckett's design was adopted and 10 miles of Whale roadway were manufactured under the management of J. D. Bernal and Brigadier Bruce White, under the orders of Churchill.

The proposed harbours called for many huge caissons of various sorts to build breakwaters and piers and connecting structures to provide the roadways. The caissons were built at a number of locations, mainly existing ship building facilities or large beaches like Conwy Morfa around the British coast. The works were let out to commercial construction firms including Balfour Beatty, Costain, Nuttall, Henry Boot, Sir Robert McAlpine and Peter Lind & Company, who all still operate today, and Cubitts, Holloway Brothers, Mowlem and Taylor Woodrow, who all have since been absorbed into other businesses that are still operating. Α] On completion they were towed across the English Channel by tugs Β] to the Normandy coast at only 4.3 Knots (8 km/h or 5 mph), built, operated and maintained by the Corps of Royal Engineers, under the guidance of Reginald D. Gwyther, who received a CBE for his efforts.

Deployment [ edit | edit source ]

Wrecked pontoon causeway of one of the "Mulberry" artificial harbours, following the storm of 19–22 June 1944.

By 9 June, just 3 days after D-Day, two harbours codenamed Mulberry "A" and "B" were constructed at Omaha Beach and Arromanches, respectively. However, a large storm on 19 June destroyed the American harbour at Omaha, leaving only the British harbour still intact but damaged, which included damage to the 'Swiss Roll' which had been deployed as the most western floating roadway had to be taken out of service. The surviving Mulberry "B" came to be known as Port Winston at Arromanches. While the harbour at Omaha was destroyed sooner than expected, Port Winston saw heavy use for 8 months—despite being designed to last only 3 months. In the 10 months after D-Day, it was used to land over 2.5 million men, 500,000 vehicles, and 4 million tonnes of supplies providing much needed reinforcements in France. Γ] Δ] In response to this longer than planned use the Phoenix breakwater was reinforced with the addition of extra specially strengthened caisson. Ε]

The Royal Engineers built a complete Mulberry harbour out of 600,000 tons of concrete between 33 jetties, and had 10 miles (15 km) of floating roadways to land men and vehicles on the beach. Port Winston is commonly upheld as one of the best examples of military engineering. Its remains are still visible today from the beaches at Arromanches, and a section of it remains embedded in the sand in the Thames Estuary, accessible at low tide, about 1,000 m off the coast of the military base at Shoeburyness. A Phoenix unit known as The Far Mulberry sank off Pagham and lying at about 10 metres is an easily accessible scuba diving site. Another unit is aground with a broken back just inside Langstone Harbour.

3. Mulberry Harbours (1944)

In to the D-Day landings of World War Two, the Allies faced a challenge in supplying their troops. German defenses made the capture of a port town extremely dangerous, and there was no guarantee it could be done at all. But once they landed, troops would soon need to be resupplied.

The solution was the Mulberry harbors, pre-fabricated concrete harbors whose component parts were floated across the English Channel and sunk in place at Omaha Beach and Arromanches. The Omaha harbor was destroyed by a storm, but the design far exceeded expectations in its durability. Meant to last three months, the Arromanches harbor was used heavily for eight months, and over a ten month period, it unloaded over 2.5 million allied troops as well as 4 million tonnes of supplies.

‘Mulberry’ Floating Harbours

Co-ordinating the effort required awesome organisation and logistics. The Allies had to marshal and maintain over 2 million men, 11,000 aircraft, and 7,000 ships in England. The prodigious industrial output to meet their requirements had to be matched by efficient distribution. The engineering work behind the landings was staggering, and thousands of construction workers were recruited to work night and day. The Petroleum Warfare Department pioneered PLUTO (Pipeline Under The Ocean), ready to pump millions of gallons of petrol across to the invaders. To get the astonishing volume of men, equipment and supplies ashore in north-western France, Churchill’s pet project, the technologically ingenious ‘Mulberry’ floating harbours, were essential. Two were to be constructed off Normandy. Over a hundred enormous 6,000-ton reinforced concrete caissons called ‘Phoenixes’ (each 60 feet high, 60 feet wide and 200 feet long) would be towed across the Channel from Selsey Bill and Dungeness by some of the fleet of 132 tugs and then filled with sand from ‘Leviathans’ so they sank to form a breakwater in the Bay of the Seine. Outside this artificial reef was a floating line of ‘Bombardons’ towed from Poole and Southampton to calm the waves, and inside, in shallower water, a line of ‘Gooseberries’, formed from two dozen redundant merchant navy vessels, Liberty ships and one old dreadnought that were scuttled and sunk where needed. In the calmer waters within the two-square-mile Mulberry harbour, strong Lobnitz or ‘Spud’ pier heads were sunk deep into the sand which allowed long bridges or floating roadways to the shore, known as ‘Whales’, to float up and down with the tides. The menagerie of code-names was augmented by power-driven pontoons called ‘Rhinos’ and amphibious vehicles known as ‘Ducks’.

Artificial Ports

When the Allies prepared for the Normandy landing, it became evident to them that the Germans would do everything possible to prevent their French ports from falling into enemy hands. They consequently decided on a surprise approach, which involved bypassing existing ports and landing on a bare expanse of beach. Two structures were designed to accomplish this purpose: landing craft of various types that were to be deliberately run aground on the beach and then opened to discharge their cargo, and artificial ports.

Churchill had conceived the idea of artificial ports as far back as 1915. In 1940, as prime minister, he thought of it again. On May 30, 1942 he elaborated on his concept in a note dispatched to Mountbatten, who for some time had pondered over the problems that would be posed by a military landing. During a meeting of the chiefs of staff, Mountbatten declared “If there are no employable ports, we can build them piece by piece and tow them over.” After reconnaissance information about Dieppe confirmed the need for “mulberries” (the code name given to these artificial ports), two of them were constructed in June 1944 for use at Arromarches and Vierville. Their use came as a complete surprise to the Germans, who had never even suspected their existence. Carried over the English Channel piece by piece, these two ports, complete with breakwaters, loading platforms and mobile jetties almost Vs of a mile in length, had a storage capacity exceeding the port of Dover. They could handle daily cargo unloadings of 6,000 tons of equipment and 1,250 tons of vehicles. The construction of these brilliant examples of British naval engineering in gcnuity, weighing one million tons each, required the labor of 20,000 men over a period of eight months, as well as 100,000 tons of steel and 8.75 million cubic feet of concrete. The Vierville port, constructed under extremely bad weather conditions, turned out to be useless. So did the Cherbourg “mulberry,” which was finished on June 27, 1944. But the Arromanches mulberry was able to discharge cargoes of 680,000 tons of equipment, 40,000 vehicles and 220,000 men between mid-July and October 31, 1944.

The artificial port used at Arromanches consisted of four basic elements. The first was breakwaters of three different sorts. One line of breakwaters was formed by filling 60 old ships with 500,000 tons of cement, which, of course, caused them to sink. Next came 146 open caissons of reinforced concrete. Six different types of caissons were made, ranging in weight from 1,672 tons to 6,044 tons they were deployed at different levels as the depth of the ocean floor increased. The largest could be used where the ocean floor reached a depth of 30 feet. These caissons, armed with Bofors guns to protect personnel, were towed across the Channel by 1,500-horsepower tugs. At the proper moment the caissons’ valves were opened they then filled with water and sank. The outermost breakwaters, cylindrical metal floats 225 feet long and 16 feet in diameter, were assembled side by side in groups of three and supported by a concrete “keel” weighing 750 tons, the upper part of which emerged six feet from the surface of the water. Anchored at a depth of 65 feet, they were placed end to end to form a floating breakwater a mile long, which took the first shock of the waves, before they struck the caissons.

The second element of the mulberries was fixed oi sheltering jetties. Floating caissons were placed end to end and sunk in lines at right angles to the shore. They protected the port from waves, and from attacking midget submarines or frogmen, and served as loading platforms for small ships.

Next were wharves made of pontoons. To keep the floating platforms at a steady horizontal level, which was necessary to avoid complications in unloading ships, they were anchored to steel braces on the ocean floor by a system of pulleys and cables. To compensate for the tides, pontoons were raised or lowered by winches. The winch operation was controlled by extensometers that were connected to the cables securing the pontoons to the steel braces.

The most difficult problem was how to maintain a continuous connection between the pontoons and the shore, which, at high tide, was about 3,000 feet away.’ In spite of the breakwaters the sea was in such constant turmoil that there was doubt as to how long floating jetties made up of several sections would behave. Exhaustive studies beginning in 1941 led to the construction of a jetty supported by floating caissons. Each 100-foot section was composed of two girders in an extremely rigid “bowstring” form, transversely connected at the center by an equally rigid strut and at different points on the strut by a number of articulated braces. The striated sheet metal deck was fixed to the various braces in such a way as to permit expansion. Thus, the ends of the two master girders could take various positions relative to one another. The whole structure was made of high-elasticity steel its components were riveted together.

The variation of the tides was such that the floating jetties needed the capacity to lengthen or shorten. For this purpose they were fitted with telescoping sections, each consisting of twin girders whose ends were enclosed in a central unit into which they could slide. In this way each section could be lengthened by nine feet.

The installation of an artificial port required a graded shoreline, depending on its composition-i. e., whether it was primarily wet sand, pebbles, marsh etc. Roads in some cases needed to be constructed from prefabricated material shipped across the English Channel and swiftly laid by engineering crews. The road-building material was sometimes prefabricated metal mats, or perhaps of mineral or vegetable origin. In this last instance a British Valentine tank was sent forward with an enormous drum dispensing several hundred feet of coconut matting. A roadway laid down in this fashion over wet or dry sand proved excellent for wheeled and tractored vehicles.

Further amazing engines onshore also sprang from Churchill’s ‘inflammable fancy’: armoured tank bulldozers and ploughs, special fat-cannoned Churchill tanks for blasting blockhouses, other ‘Crocodile’ Churchill tanks that could squirt petrol and latex flames over a hundred yards, great machines for laying fascines across mud or barbed wire, or for thrashing their way with flailing chains clear through exploding mine fields. These devices came from Churchill’s direct encouragement and protection of a brilliant maverick, Major General Sir Percy Hobart of 79th Armoured Brigade, and were collectively known as ‘Hobart’s Funnies’.

The deception plan for NEPTUNE, the cross-Channel attack, was called Plan FORTITUDE, and its object was ‘to induce the enemy to make faulty dispositions in North-West Europe’. FORTITUDE NORTH aimed to keep Hitler worrying about Scandinavia, and the danger to Germany posed by an Allied attack on Norway and Denmark. Dummy wireless traffic and bogus information from double agents indicated that the (notional) British Fourth Army in Scotland, supported by American Rangers from Iceland, was going to attack Stavanger and Narvik and advance on Oslo. British deceivers also worked hard on the neutral Swedes. The commander-in-chief of the Swedish Air Force was asked for ‘humanitarian’ assistance in the event of an Allied invasion of Norway. As his office was being bugged by the pro-Nazi chief of Swedish police, this information went straight to Berlin. When Hitler read the transcript he ordered two more divisions to reinforce the ten already in Norway. Thus 30,000 more soldiers were diverted away from France.

The Cunning Plan

Planning for D-Day started in March 1943, although it had been known since Jan 1942 that there would be an invasion, and the Allies, especially the USA, were already building up their men and materials in preparation. The problem was ships.

Flat-bottomed landing ships couldn’t deliver the assault forces and then go on to deliver the continuous stream of weapons, vehicles, men, fuel, armaments and equipment needed to sustain them in battle. That would have to be done by ordinary cargo ships. Thankfully, the USA was beginning to outstrip merchant ship losses to U-boats in the Atlantic with their Liberty Ship programme. The problem was that ordinary deep-keeled merchantmen needed a port to unload, and there weren’t any of those on the coast of Europe. Nor were any likely to become available quickly even if captured. The Germans would do all they could to sabotage them. So, the Allies had to build their own port. As Lord Louis Mountbatten said: “If we can’t capture a port we must take one with us.”

So, the plan starts with breakwaters, to afford ships large and small some protection and sheltered water. The allies decided to build breakwaters with floating ‘Bombardons’, scuttled ships and concrete ‘Phoenix’ caissons.

Bombardons were 200 ft concrete & steel tubes with a x-section in the shape of a cross. Three blades of the 2,000 ton Bombardon were below the water so the fourth made it look like a floating wall. They were strung together with fifty foot gaps between them and anchored to the bottom. Twenty-four bombardons would make up a mile of breakwater – and that was their function, to flatten out the wave movement. Bombardons and scuttled blockships were allocated to all the D-Day beaches. The breakwaters of the two Mulberry harbours at Arromanches (Gold) and Saint Laurent-sur-Mer (Omaha) were made up of blockships and Phoenix caissons scuttled 2 kilometres offshore.

Mulberry B at Arromanches (Photo: IIWM Non Commercial Licence) Swipe left or click arrow for more

Phoenix Caissons with AA towers. A sunken blockship in the background. (Photo: Public Domain)

An anchored string of floating bombardons (Photo: USN)

At the end of May 1944, 55 old warships and cargo ships were gathered in Loch Linnie, Scotland where they were prepared for scuttling, with explosives and concrete ballast. Then they set off with an escort to join the gathering fleet for D-Day. Meanwhile on 4th June, 146 giant concrete ‘Phoenix’ caissons of varying sizes, which had been constructed in secrecy over the previous 9 months and then sunk to hide them, were refloated and began their slow (4 knots) journey to Normandy, towed by 85 tugboats.

You’ve got to admit, that is spectacular planning and organisation on a grand scale, and we haven’t even talked about the piers!

Again, all this has to work across a huge tidal range. So a great deal of testing was involved in designing the wharves and piers heads needed to unload a large share of the estimated 38-40,000 tons of supplies needed daily.

Essentially the system works around huge wharf units fixed in position on four legs like an oil rig, and allowed to float up and down with the tide. This type of wharf is called a “Spud” wharf, but the wharf units in the Mulberry harbours were called Loebnitz wharves². These are connected to the shore by a flexible roadway up comprising 80 ft bridging spans on floating concrete pontoons (“Beetles”). The causeways could be up to a kilometre long in order to place the wharves in water deep enough to allow a fully laden cargo ship alongside at low tide.

Mulberry B (Courtesy The D-Day Center)

There were several causeway & wharf platforms (piers) at Mulberry B to allow for unloading offshore. The east pier was the pier for unloading tanks, bulldozers, artillery and other military vehicles from LSTs (Landing Ship Tank). It had one causeway because all the traffic was self-driving.

The main wharf was made up of seven platforms, allowing up to seven ships at a time to be unloaded. This was the general supplies wharf (food, medicines, clothes, materials, equipment, etc). This had two 1.2 kilometre floating causeways so a continuous stream of empty trucks could drive out on one, load up, and return to shore on the other.

To the west of the main wharf there is the pier for ammunition barges, and west of that, an interesting pier called a ‘Swiss Roll‘. It was a floating road surface, which in trials had proved capable of handling light vehicles up to 7 tons.

Mulberry Harbours

Because of the lack of any adequate deepwater ports along the open stretch of the Normandy coast selected for the assault it was necessary to provide shelter and large-scale unloading facilities for the build-up, until such time as Cherbourg and Le Havre could be captured and put into operation. Two quite separate projects were undertaken to fulfil these needs – Corncob and Mulberry.

‘Corncob’ provided artificial breakwaters by scuttling blockships – four old warships and 54 merchant ships – off each of the assault beaches. The five shelters, which were code-named Gooseberries and were laid between 7 and 10 June, formed a lee for the smaller landing craft and also served as bases for maintenance and repair parties the French battleship COURBET continued to fly her ensign and man her AA armament.

The two ‘Mulberry’ harbours were far more ambitious in their concept and execution. Each was to provide a sheltered anchorage equivalent in area to Dover harbour, with unloading facilities which could handle 6,000 tons of stores and 1,250 unwaterproofed vehicles daily by the fourteenth day after the initial assault due to a lack of tugs, these targets were extended, four days before the operation began, to the twenty-first day. The life of the harbours was to be 90 days.

Each Mulberry comprised three main components:

  • 200-ft floating steel cruciform structures moored end to end offshore to reduce wave energy and provide shelter for a deepwater anchorage in practice, they were found to reduce wave height by up to 40 per cent.
  • Concrete caissons, uniformly 200 feet long but varying in displacement between 2,000 and 6,000 tons, sunk on the 10 metre (5% fathom) line to form breakwaters for the inner harbour the Gooseberries off ‘Juno’ and ‘Omaha’ beaches were incorporated into these breakwaters. The Phoenixes also provided accommodation and AA gun positions for the defence of the harbour.
  • the floating pierheads, piers and roadways within the port prefabricated in steel and concrete sections, they were assembled on arrival. Like the Phoenixes, the Whales were a War Office design and production responsibility: towing characteristics were not prominent among the design criteria and caused problems – after the loss of four Whale tows through bad weather, sailing in wind strengths above Force 3 was not permitted.

The moorings for the Bombardons were laid off ‘Omaha’ (Mulberry A) and Arromanches (Mulberry B) on D+ 1 and the first units were moored on the next day. Phoenixes were laid down from D+3 as surveys of the intended lines were completed and on the same day the first Whale pier was begun in the Arromanches harbour. The bad weather interfered with the programmed work but by D+ 10 piers were operational in both harbours and Mulberry B was handling a dozen coasters and 1,500 tons of stores daily Mulberry A was not quite so far advanced.

Between noon on 19th and midnight 20th/21st June, the Channel and Seine Bay were affected by a Force 7 gale which produced waves of an average height of eight feet in the assault area. The more exposed Mulberry off ‘Omaha’ beach was wrecked, two thirds of the Phoenix units collapsing and the main pier destroyed by up to 30 LCTs and other craft being driven against it. Mulberry B was more fortunate and remained virtually intact, although over 800 craft of all types from LCTs downwards were stranded When stock was taken of the damage and loss (which included 22 Whale tows – 2½ miles of roadway – which sank offshore), it was decided that Mulberry A would be abandoned and all resources would be devoted to clearing and expanding the Arromanches harbour. The ‘life’ of the harbour was to be extended to permit it to continue operating into the winter.

After Neptune

The surviving Mulberry was not completed until 20 July. It was, however, already operating beyond its planned capacity and an average of 6,750 tons per day was cleared between 20 June and 1 September. Compared with the tonnage delivered over the open beaches from LSTs, LCTs and lighters – a daily average of 15,000 tons over just the two US beaches, this ‘dryshod cargo’ figure may not seem impressive, but among its other virtues the Mulberry was able to handle certain loads which could not be simply driven ashore. Cherbourg fell to the US Army on 27 June but the very thorough German demolition of the facilities prevented its reopening until September thereafter, a daily tonnage of 12,000 was soon reached.

The Arromanches Mulberry remained open well into the autumn for although Le Havre and Antwerp were captured during the first half of September, neither could be reopened until November, the former because demolition, by the RAF as well as the retreating Germans, had been so comprehensive and the latter because the heavily-mined approaches to the undamaged port were dominated by enemy-held territory, necessitating a further major amphibious operation (the invasion of Walcheren), followed by a major mine clearance operation before the first cargo could be delivered. Antwerp was opened to large ships on 28 November 1944 and, with a daily capacity of 40,000 tons, thereafter became the principal Allied supply port for the advance into Germany.


Arromanches-les-Bains (French pronunciation: [aʁɔmɑ̃ʃ le bɛ̃] ( listen ) or simply Arromanches) is a commune in the Calvados department in the Normandy region of north-western France.

The inhabitants of the commune are known as Arromanchais or Arromanchaises. [2] [3]


Arromanches-les-Bains is 12 km north-east of Bayeux and 10 km west of Courseulles-sur-Mer on the coast where the Normandy landings took place on D-Day, 6 June 1944. Access to the commune is by the D514 road from Tracy-sur-Mer in the west passing through the town and continuing to Saint-Côme-de-Fresné in the east. The D87 road also goes from the town south to Ryes. The D65 road goes east to Meuvaines. About a third of the commune is the urban area of the town with the rest farmland. [4]


Arromanches is remembered as a historic place of the Normandy landings and in particular as the place where a Mulberry harbour artificial port was installed. This artificial port allowed the disembarkation of 9,000 tons of material per day.

It was on the beach of Arromanches that, during the Invasion of Normandy immediately after D-Day, the Allies established an artificial temporary harbour to allow the unloading of heavy equipment without waiting for the conquest of deep water ports such as Le Havre or Cherbourg. Although at the centre of the Gold Beach landing zone, Arromanches was spared the brunt of the fighting on D-Day so the installation and operation of the port could proceed as quickly as possible without damaging the beach and destroying surrounding lines of communication. The port was commissioned on 14 June 1944.

This location was one of two sites chosen to establish the necessary port facilities to unload quantities of supplies and troops needed for the invasion during June 1944, the other was built further West at Omaha Beach. The British built huge floating concrete caissons which, after being towed from England, then had to be assembled to form walls and piers forming and defining the artificial port called the Mulberry harbour. These comprised pontoons linked to the land by floating roadways. One of these ports was assembled at Arromanches and even today sections of the Mulberry harbour still remain with huge concrete blocks sitting on the sand and more can be seen further out at sea.

Some key figures: by 12 June 1944 more than 300,000 men, 54,000 vehicles, 104,000 tons of supplies had been landed. During 100 days of operation of the port 2.5 million men, 500,000 vehicles, and 4 million tons of material were landed. The best performance of the port was in the last week of July 1944: during those seven days the traffic through Arromanches exceeded 136,000 tons or 20,000 tons per day.

Today, Arromanches is mainly a tourist town. Situated in a good location for visiting all of the battle sites and war cemeteries, there is also a museum at Arromanches with information about Operation Overlord and in particular, the Mulberry harbours. [5]

On 21 September 2013 Bradford-based sand sculpting company Sand in Your Eye created a tribute called "The Fallen 9,000". It was a temporary sculpture project—a visual representation of 9,000 people drawn in the sand which equates the number of civilians, German forces and Allies that died during the D-day landings. It coincided with Peace Day, and was washed away with the tide at the end of the day. [6]


Azure, an anchor of Or debruised by a mullet of Argent between two chains of Sable posed in chevron inverted broken, in chief Gules debruised by a leopard of Or armed and tongued Azure.

Watch the video: Bob Larbey discusses end of Mulberry (August 2022).