Whilst not local history, this article relates to the history of a ‘local’ –one of the Society’s Honorary Life members, Les Bloom, who has been a member for over 50 years. As an apprentice, Les was working on pressure vessel manufacture with Webster, Clough & Co Ltd in Bradford, when he was put in charge of some secret development work in connection with the World War II D-Day preparations of the Ministry of Supply. Les, who over time became a Chartered Engineer, received this responsibility as being particularly numerate and able to understand the specifications. He carried this responsibility while studying in the evenings. The component of the harbour he worked on was codenamed ‘Bombardon’. This article is a local contribution to the National Victory in Europe celebrations.

Chris Alder

The Mulberry Harbour Project

Twenty million pounds (sterling), 40.000 men, 144,000 tons of concrete. 85,000 tons of ballast and 105,000 tons of steel were all part of the building of two major ports, each the size Of Dover, transporting them in large sections over the English Channel – under the eye of the enemy – and establishing them on the coast of France in high seas; this was what the Mulberry Harbour project was all about. It was of the greatest engineering feats of World War Two and there can no doubt that Mulberry played a decisive part in the success of the invasion of Europe in June 1944. “Mulberry” and other code names were words appearing in the Daily Telegraph crossword puzzle in the month prior to the invasion!

Harbour Description

Fifty nine Obsolete merchant and naval vessels were ballasted and fitted with explosive charges, crossed the channel under their own steam, to be sunk in the required positions to form one of three forms of break waters at the two sites – Mulberry ‘A’ at Omaha for the Americans and Mulberry ‘B’ at Arromanches for the English and Canadians. These break waters were codenamed “Gooseberry”.

Immediately after this, the first pontoons known as “Phoenix” began to arrive. These were concrete caissons, weighting between 3,000 and 6,000 tons, measuring 220 ft by 52 ft by 60 ft high – towed by tugs and sunk as the old merchant ships on the Calvados reefs. They formed a 4 mile-long breakwater and were one and a half miles from the shore.

Floating breakwaters (Bombardons) moored in Weymouth Bay during experiments.

Floating breakwaters (Bombardons) moored in Weymouth Bay during experiments. Copyright: © IWM. Original Source:

A massive outer floating breakwater was formed codenamed “Bombardon” – which was constructed from large steel sections, all linked together on site.

THE MULBERRY HARBOUR (H 39297) Construction in Britain: A Spud pierhead unit parked awaiting D Day. These were fitted with legs to enable adjustments to be made according to the state of the tide. Copyright: © IWM.

THE MULBERRY HARBOUR (H 39297) Construction in Britain: A Spud pierhead unit parked awaiting D Day. These were fitted with legs to enable adjustments to be made according to the state of the tide. Copyright: © IWM. Original Source:

Pier heads were then established – “Hippo’s”- to unload the ships. These were floating platforms made of steel, each corner of which was a ‘spud leg’[i], which were lowered on to the sea bed, where they were held firm by the pressure while the platform moved up and down with the tide. The pier heads were linked to the shore by floating roadways – “Whales” – made of small concrete pontoons linked by metal bridges – “Beetles” making a 4,000 ft long roadway. There were 4 of these floating roads, one for landing light vehicles such as ambulances, command cars and jeeps, one for heavy vehicles such as tanks, bulldozers and cranes, and two for unloading various cargoes. In addition to these unloading capabilities, there were about 350 dukws plying constantly between ships and shore. At times there could be 280 ships unloading at the same time in the harbour.

Construction in Britain: A section of the floating causeway parked awaiting D Day. Copyright: © IWM.

THE MULBERRY HARBOUR (H 39295) Construction in Britain: A section of the floating causeway parked awaiting D Day. Copyright: © IWM. Original Source:

Use and Development History

The American harbour (Mulberry ‘A’) was not securely anchored to the bed and was soon severely damaged by the worst period of severe weather, but parts were rescued to maintain Mulberry ‘B’ and in due time this became known as Port Winston. Prime Minister Churchill himself had put immense pressure on the designers, manufacturers, the military and naval top brass, and the Ministry of Supply to achieve his objective. He knew, after the disaster of Dieppe in 1942, when 3,000 men were killed or captured, that the German forces would defend or destroy ports to prevent their use by an invading force. What was required was an artificial harbour which could be pre-fabricated, then taken across the Channel for installation on the chosen landing beach. This would have to be designed, tested. and then built in a very limited period of time. In a directive which he wrote on 30th. May 1942 to Admiral Mountbatten, who had been appointed to command Combined Operations, he said about the piers “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!”

Secrecy and security were of paramount during the design, manufacture, and trials of the two harbours, despite the fact that all the large and small engineering and construction companies throughout the country had to be involved. Garlieston in Wigtownshire, Scotland was the area chosen for the long lasting and frustrating trials and the D-Day Landing Museum has been set up there.

The whole business was immense and beyond many contributors’ comprehension and yet, when the day arrived, success was achieved and in the 5 months Port Winston (Mulberry ‘B’) was in use, over 2 million men, half a million vehicles and 4 million tons of supplies passed through the harbour.

A Personal Perspective

This account started by mentioning the 40,000 men involved – I was just one young engineer of those 40,000 engaged in a very small part of the system. We had no idea what the total scheme was about, it was top priority and top secret, we were just pushed and pushed by the Ministry of Supply to build and test large components of “Bombardon” as quickly we possibly could – the work was spread around the country and changes in design had just to be accommodated, still maintaining delivery times – they clearly knew the dates were critical.

What vision and what pressure – no wonder Winston liked his brandy!!

Les Bloom

Further Resources:

Engineers at War: Mulberry Harbour

Think Defence: The Mulberry Harbour – a comprehensive history

The Imperial War Museums collection: search for Mulberry Harbour

[i] A spud leg is one placed at the corner of a working platform that can be lowered to the sea bed and enables the platform to be jacked up above sea level, thus providing a stable surface