MULBERRY HARBOUR

MULBERRY
This was the official name for the complete harbour installation. There were to be two complete harbours, Mulberry A for US forces and Mulberry B for British use.

PHOENIX
These were concrete caissons of five different sizes, the largest of which were 200’x60’x60’ and each unit weighed between 6044 tons and 1672 tons They were airtight floating cases open at the bottom with air-cocks to lower them to the sea-bed in a controlled fashion. Around 2 million tons of steel and concrete were used in their construction. They would form a breakwater to protect the harbour.  146  were constructed  by well known civil engineering contractors in 28 different locations  mostly in the south of England, including East India Dock [which had been drained for the purpose], South Dock, Millwall, Red Lion Wharf, Northfleet, Southampton Docks, Portsmouth Dockyard and Beaulieu River. When completed they were towed to locations off Selsey Bill and Dungeness and partially sunk on the sea bed to help avoid detection. An early trial  showed that a 750ihp tug could tow the largest units at 3 knots in ideal conditions.

GOOSEBERRY
A harbour of refuge for small craft  formed by sinking obsolete merchant and naval vessels on the 2 fathom contour.  70 obsolete merchant vessels and naval vessels  were amassed at Oban on the west coast of Scotland, stripped down, ballasted and primed with explosive scuttling charges. Some proceeded to the Channel under their own power, others were towed. They were concentrated at Poole Bay until required. This was known as Operation Corncob. 

BOMBARDONS
A floating breakwater comprising a steel cruciform structure which was used where the water was too deep to use either Gooseberry or Phoenix breakwaters. Each unit was 200’ in length. They  were the outermost barrier and therefore the first line of defence against rough seas.

LOBNITZ PIERHEADS
Constructed by the well known Clyde based shipbuilders and engineers in a special facility at Leith. These were complete pier head units, secured to the seabed by a ‘spud’ at each corner which could be mechanically adjusted to compensate for the rise and fall of the tide.

WHALE
The floating roadway which connected the line of Lobnitz units to the beach and were supported by floating pontoons called beetles.

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It will be appreciated that with the exception of some of the Gooseberry vessels every component of the harbour would have to be towed from the manufacturing site to the operational area, either free floating or on barges or pontoons.  A pool of 158 tugs was estimated to be sufficient. Agonising decisions had to be taken in regard to this tug procuring process, not least of which was whether to re-deploy rescue tugs then currently engaged in convoy rescue duties. Throughout the operation the most acute  problem was the tug shortage, which was never satisfactorily remedied. The target date for completing Mulberry had, as a result, to be postponed.  [Even after VE day there was still an acute shortage of tugs and a directive was issued urging that now redundant A/S trawlers should be pressed into service for towing barges etc]

 In August 1943 it was stated that 50, 750hp and 40 ,1000hp tugs would be required. A tug census was taken by the Admiralty and MoWT and it was decided that 65 tugs could be provided for a limited period.  This could only be achieved by:-

 

1] Withdrawing 20% of tugs from commercial ports.

2] Suspending coastal towing operations.

3] Withdrawing 30% of rescue tugs.

4] Withdrawing 25% of Admiralty dockyard tugs.

 

It was hoped the shortfall would be made up by US tugs but by  December 1943 delays in deliveries of US tugs caused more anxiety and Churchill called for another tug census. Requirements for Mulberry towage had now risen to 154 tugs and for other work in connection with the invasion a further 36 tugs could be required.  

 

On 19th May 1944 Capt E J Moran USNR [A member of the American tug owning family] was appointed Tug Controller. He was made responsible for the control of over 200 tugs involved in the assembly, assault and build up stages of Operation Overlord.

A special body, known as COTUG, was organized on the 24th May 1944 under ANCXF to deal with all Mulberry tug problems. In charge of COTUG was Capt. J G Y Loveband RN. with Commander F H E Vaughan RNR as deputy.  There were not enough tugs in the country, however, to satisfy all Commercial, Naval and Military demands for their services.

As late as 31st May 1944 only 48 out of 72 large, and only 4 out of 44 small tugs allocated for towage of Phoenix and Whale units were available. On that date Admiral Ramsay directed that "the principle, that Mulberry and construction constituted a vital part of the whole operation, must govern decisions as to the extent that tug assistance could be provided for other purposes". The operation finally commenced with a total of 132 tugs, 72 British, Dutch or French and 60 American. Out of this total 97 tugs were suitable for cross-channel tows and 35 were small handling tugs, only really suitable for use in sheltered waters.  On 18-12-1944 COTUG was relocated from Lee-on-Solent to offices in Bryanston Square, London.

A statement to Parliament in March 1945 reported "One hundred and thirty-two tugs, including British, American, French and Dutch, were employed in towing the units of this harbour from sheltered anchorages in the United Kingdom to the Normandy coast. Nearly 1,000 tows were made for this purpose in June and July. Tugs were mobilised from far and wide to accomplish this mighty task, made the more daunting by the rough and unseasonable weather in the Channel. The moorings in the British area alone included 242 buoys, requiring the handling of 3,265 tons of mooring gear."

 

COTUG ceased to exist at 2359hrs 13 July 1945, and the pool of Overlord tugs ceased to exist with it. After that date all control of US tugs reverted to the US authoroties, the Admiralty resumed control of all rwescue tugs, and control of all other tugs reverted to MoWT or Naval Director of Sea Transport. This included foreign flagged vessels still on charter. The shortage of tugs had never been solved and commanders of captured continental ports were still fighting to hang on to their allocated vessels.