D-Day 70th Anniversary: The Mulberry Harbours

By Gavin Greenwood | Updated: 04 June 2014

Mullberry Harbours - the portable temporary harbours developed by the British in World War II were vital for  the Allied invasion of Normandy. Gavin Greenwood explains

a black and white photo of a floating harbour
Mulberry Harbour, Arromanches: Lorries on the spud pierhead as Britain's Mulberry Port at Arromanches begins to operate as a harbour. Several small vessels are tide up to the pierhead.© IWM (A 243731)

Spuds, Beetles, Whales and Gooseberries were all a vital part of the massive effort to invade France on June 6, 1944. They were code names for parts of the Mulberry Harbours, strategically vital temporary harbours made from floating sections of concrete.

Although the Allied command recognised that they could successfully land a large force on the Normandy beaches with little serious interference from the Luftwaffe or the German navy, concerns remained over reinforcing and resupplying the units ashore.

Until a major port (Cherbourg) was captured that was able to handle the huge amounts of cargo and reinforcements, there remained the problem of how to sustain the drive towards the German frontier.

18 months of planning had produced an elaborate and highly theoretical resupply model that was dependent on rigid loading plans and shipping schedules. The model overtook pragmatism with its complex charts and graphs, creating uncertainty and anxiety at the highest levels.

photo shows a large concrete construction forming a harbour set into the sea

Mulberry elements in position off Normandy. Ack-ack or anti-aircraft guns can be seen. The floating concrete caissons making up the two harbours were equipped with guns, up to 12 tons of ammunition, and a crew of up to 12 men to pilot them over the channel

The British response, largely directed and driven by Churchill, was to construct two huge artificial harbours that could be built in sections and towed across the Channel for final assembly at the main Allied beachheads.

Codenamed 'Mulberry,' the harbours consisted of floating concrete sections (Phoenixes) that when joined together formed huge quays and cargo-handling platforms for the US and the British beaches.

Absorbing some 2 million tonnes of concrete and steel, the artificial harbours also contained a complex infrastructure of pier heads (Spuds or Lobnitz to the Americans), around 16 km of floating roadways (Whales) supported by pontoons (Beetles) enclosed within a 'lagoon' of specially constructed breakwaters (Bombardons) and 70 scuttled ships (Gooseberries). Rhino pontoon ferries and DUKW ('Duck') amphibious trucks would supplement the port

The Phoenixes were built on both the River Thames and River Clyde, the Beetle pontoons were assembled in Richborough, Kent, at Southsea, Marchwood and Southampton and the pier-heads and buffer ramps at Conwy in North Wales. Once completed, the floating sections were towed to assembly areas off Selsey in West Sussex and Dungeness in Kent until their final journey across the Channel.

The Mulberry plan attracted a number of sceptics, including many from the US Navy familiar with the amphibious war in the Pacific and the mechanics of the 'fleet train' supply system that carried men and material thousands of miles from the American West Coast, over coral reefs and on heavily defended beaches.

The destruction of the US Mulberry A in a major storm on 19-20 June showed this view to be largely correct as it forced the navy to beach landing craft and unload directly onto the sand. Efforts to follow the complicated landing schedules and loading sequences produced by countless hours of staff work also proved futile and were abandoned by the frontline troops as early as 8 June.

These factors, based in the improvisational skills and energy of soldiers in the field ensured enough ammunition, food and other essentials were readily available.

In many respects the Mulberries' main role was in offering assurance to the planners. The cost and effort that went into the harbours, the remains of which will serve as reminders of D-Day until the sea reduces them to the sand they were built of, gave confidence to most of the politicians and planners responsible for the invasion.

Explore the background to the D-Day landings

Find out about the training and deception involved in the D-day landings

What happened on D-Day? The Normandy Landings of June 6 1944

Explore some of the locations and museums in Normandy today that tell the story of D-Day

Read our feature on the different types of tank or Hobart's Funnies, developed for the D-Day landings

Read our timeline of events leading up to D-Day

Click here to explore D-Day web links

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