• Nie Znaleziono Wyników

Mulberry harbour 1944-1994

N/A
N/A
Protected

Academic year: 2021

Share "Mulberry harbour 1944-1994"

Copied!
36
0
0

Pełen tekst

(1)
(2)

II

il

II II I

.

''

~

' "

E

'." ,fNGINEER'rhQmas , , , l,JIerQn

r~;

i" . , ' ,, " " "" Q " tI'a ,.." L' , Q , ndQn ,, ' , E~: 4JD. , ., , ) 071.5384656. .n."". ."n..."",,, FAX:.(Glassified) c 07U538 1228. FAX:(AllQther areas):071-5385746.

NORTHERNEDITORIALOFFICE:270 Carmel RQad

NQrth,DarlingtQn,CQ.DurhamDL39TD. TEL:(0325)461149.FAX:(0325)484870.

MulberryHarbour1944-1994is pub-lishedasa supplementto NewCivil

Engineer andis sponsoredbythe

fol-lowing fIrms which worked on the project50years ago:Amec, Balfour Beatty,Bovis,OscarFaber,Franklin &Andrews, Sir Alexander Gibb& l'artIle~s, ,Kier, John. Laing, John MowlemConstruction,EdmundNut-tall, ScottWilsonKirkpatrick& Part-ners, Tarmac,Taylor Woodrowand TrafalgarHouseConstruction.

ttr_-

c.-

r J

I Ii

-t- .,

,'rm

.. - ..#

Edited

by Mike Winney.

WrittenbyWill Howie.

Interviews researchedand written byJackie Whitelaw, Mike Winney andthe Mulberryparticipants them-selves. Other contributions are aCknowledgedin the relevant arti-cles.

Picture researchbyMary Mmphy, ICE archivist, and the sponsoring companies.

Arromanches 1994 photographsby GrantSmith.

DesignbyAlex Morgan.

Producedby MarkAldersonand Gill Rastall.

GraphicsbyAntheaWilkie. Editorial assistance

by

Elyana Rosenthal, Nichola Stubbs and Michelle Bishop.

Cover photographbyGrant Smith, insetbyImperial WarMuseum.

Editorial.&fublishing pirector:

SimonMiddelboe

Sales Director: Gra1mmHarman Grou):lProdtictionManager: Mauro Ckiarletti

Production Executives: Diana Mackenzie, Simon ODodes

CirculationManager:Derek'lB1mn

....

... I @ThQmasTelfQrd Limited 1994

Thomas 'lBlfordLtd iswhollfj owned by the Institution ofCimlEngineers, 1 Great GeorgeStree~ L~SW1f Printed by TfLfriTiters ((jK}Ltd, Kidderminster, Ubrcs. Repro:Opu$ Bureau and Damat

(3)

'Pau-_m.im8I J!S!IIIII

I

Riftyyears

ago yesterday the first

mammo,thelements

of the Allies'

lfuZbetr'llprefabrieated

harbours

wer.oset down ontke seabed

off

Arromanches,

NO'f'11l,(J/f//Iy.

Mulberry

W8;San'auda(jiouse()(ttxJfJ/P~which

made theAtlant~cWaZZ(Jlefence'

system irrelevant at a.str()lle. The

h(Jrb,ourswereprefabric,(Jtedin

.8fi;~ain.through. th(Jwinter.()fJ/J43in

aftllrlous project which wok

!prefJedenceover all otherwo~k of the

eo~tructwn'iMustr1J.

Th'is1:s,fke

st(]fJJ'()ft'4(Jtprojeet

(Jnd\itfb,fJi

~.

.(j)!it8

f/ieter8iJ1;s;

(4)

-,

II

I

I

Introduction

to the beaches by landing craft and the like, the heavy burden of supply and reinforcement could not be car-ried in that way.For such a task, har-bours were needed. But the ill-starred raid on Dieppe in the sum-mer of 1942, in which 900 soldiers were killed and 2000 others cap-tured, revealed clearly enough that the Germans would defend any ports that they held with both determina-tion and skill. Furthermore, they could be expected to hold on long enough, as was shown later at Cher-bourg, to render a port unusable for

months. Not onlywould the Germans wreck any harbour out of which they were forced before they went, but

the attack would itself probably

destroy the facilities rendering the port useless.

In any case, the Normandy coast-line chosen for the invasion offered little in the way of ports, and none of those in nearby Brittany were likely to be captured in less than two months after the initial landings. So the first build-up of men and mater-ial would have to be made over open beaches, and these would need to be

I

10. J'bnlia. .:ilrn..

_ita\.U.

PlliliS I'O!{ uS!!: uN IJE,\CtlliS

C.C.O.

-

or depuw.

The}' must 11.01J.tup lUlUdown \'Iitll the tide. Tile l:tlchor problem I.lust be master-cd. me have the best solutiun \'Iorlmd out. Don't

Let

argus tile :.iB.ttel'. 1'01' themselves.

The d1f'.i'icultiea l'Iill lJ.!'b'll6

I

50. 5. 42.

adapted to make them capable of landing and supporting an army, 30 divisions strong, in the first crucial weeks after D-Day.

So there was no real choice. Har-bours were needed and, since they could not be captured, they had to be built. This awesome decision was taken quite early in the war, even before the failure at Dieppe had underlined its necessity. Plans were put to the Chief of Combined

Opera-tions in May 1942, and Wmston Churchill'sfamous note 'Piers for use on beaches' cameat the end of that month:

"CCO or deputy.

"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."

If harbours were needed, they

would have to be prefabricated ones, built in Britain and towed across the Channel to be assembled in position immediately after the first troops had set foot on land. They also had to be partly operational after the first fortnight and be expected to remain in use for 90 days after which they would no longer be required.

(5)

Win~ton Churchill visiting a Mulberry Harbour prefabrication site:

-Ii ";: .. a. E

(6)

:> I .. ...

H

x

u

-r

I

o

""

I i

Conception

and

prefabrication

I

T

wo features of the project stag-ger the imagination. When the fmal decision was taken at the

end of1943,there were to be two

Mulberry harbours, not one. The British were to construct one of them at Arromanches, MulberryB, and the Americans the other, Mul-berry A, further west at St Laurent.

But each of these was to be bigger than Dover harbour. They had to be prefabricated in seven months and then assembled in Normandy in a matter of days.

Dover harbour had taken seven years to build, and that was in peace-time. Luckily, some of the basic necessities were already in place. Sir Bruce White, by then a brigadier, had been in charge of port engineering since early in the war. White was a well-known civil engineer and had

.

6

.>

served in the Royal Engineers in the First WorldWar.In civil practice, his consulting firm had specialised in transport systems and port

engineer-ing.

Hewas one of the fIrst to realise that, in regaining a foothold in Europe, it would not be enough

merely to rehabilitate captured ports but new ones would have to be built. White had the foresight to assemble a brains trust of consulting engi-neers and to organise a consortium

of civil engineering contractors

which could be gathered together for just such a project. Not only that, he had been involved in developing an experimental floating pierhead with moveable spud legs and a shorearm which could be, and later was, adapted for Mulberry.

What of the harbours? As an

offi-cial publication put it, some months after the invasion: "The harbours themselves are simple - there are really only three items in their com-position - but these three items are remarkable for their vast scale and the detailed work which has gone into their simplicity, for the manner in which they came into being on the 'far shore' and for the speed of pro-duction of the whole.

"The breakwaters to give shel-tered water; the pierheads or float-ing quays at which ships could unload, and the floating roadways connecting the pierheads with the land over which motor transport and fIghting vehicles could pour.

"Lastly the beaches themselves, safe within the enfolding arms of the breakwater, were made useable dur-ing all states of the weather for that

wonderful American contribution to

victory

-

theDUKWS,or amphibious

lorries which went alongside ships in the harbour, loaded up and dashed ashore. The harbour seemed to be as full of these strange craft as London streets are with motor cars."

That of course, was written as pro-paganda material aimed at raising the morale of the troops and others who read it. But, even if it is slightly overwritten for today's taste, it does convey, accurately enough, the

sim-plicity of the project and its

grandeur. It does not, however, say just how difficult that simplicity and

grandeur had been to achieve. The breakwaters were to consist partly of enormous reinforced con-crete caissons (known as Phoenix) and partly of sunken blockships (Gooseberry). These would protect

(7)

I I I I -r I II 1M

E

u

L

E. \ ...

o

u

, ..

Photographyy./as taboo on

Mulberry'construction site,

so draughtsman C R Smith

sketched the scene at Russia

Yardearly in1944.

BELOW: Bassett-Lowke model of Mulberry

components showing the

Phoenix caisson breakwater,

pierhead jack up quay and parts for the Whale floating jetty.

INSET: The soene at Normandy.

I"

the pierheads and shoreanns and provide calm water for moored ships

and other craft. The breakwaters would themselves be protected by giant steel booms (Bombardons) floating further out to sea. Three beaches which were added to the

project later were protected by

Gooseberries only. All these code names were chosen at random. None of them had any special or psycho-logical significance except, perhaps, Bombardons which was intended to convey the impression that they had something to do with anti-aircraft defences, perhaps as a cover.

That simple pattern had onlybeen developed after considerable discus-sion and even dispute, some of it between the services involved. It is hard to say who fIrst proposed the necessity for an area of sheltered water in order to supply the troops and maintain the impetus of the invasion after the initial landing. Bruce White is an obviouscontender, but is has been suggested by Guy

Hartcup in his invaluable studyCode

name Mulberry (published by David

& Charles in 1977) that the most

likely candidate was John

Hughes-Hallett, then a Commodore in the Royal Navy and later a Vice Admiral. Hughes-Hallett had proba-bly given a substantial amount of thought to the problems attached to invading the Continent for he had been the naval commander at the

Whalefloatingroadwaysat highandlowwater

Position at high water

/

Telescopic span closed

Position at low water

/

Telescopic span open

9 JUNE 1994NCE MULBERRY HARBOUR SUPPLEMENT

(8)

!I

I

I

CAlle,«' frrrangemclI' of a spud pier/Hlad

Dieppe raid and, by 1943, was the naval Chief of Staff to the planners of Operation Overlord, as the invasion was known. But Hughes-Hallett was reported as saying that "an engineer called GuyMaunsell" had shown him plans for an artificial breakwater as

early as 1940.

Be that as it may,by the middle of 1943, the idea was being taken seri-ously. No doubt, this was partly because of Churchill's note of the previous year but also, perhaps, because the Prime Minister had pro-posed an artificial harbour using concrete caissons in operations to

'" capture the Frisian islands of

"3: Borkurnand Sylt towardthe end of

=E the previous world war. This

proposi-~

tion was not unlike Mulberry, but

<t: was never used.

.;;' Naval ideas for a sheltered haven

.~ were, not unnaturally based on the

~

obvious naval solution, that is, the

~ use of blockships, scuttled in posi-~ tion and left there. Numerous other

~

proposals appeared, usually

depend-~

ing on the suppression of waves by

65 means of compressed air pumped

"I

wastornbetweenbeingpleasedandwantingthemto

stopabusingtheequipment."

"1

*"~ Allan Beckett was a key engineer in

the conception, design, fabrication and assembly of Mulberry's floating piers. Now at 80 he is still active as a consultant to the Beckett Rankine Partnership.

I

"My involvement with Mulberry

began in the summer of '42. I was working in the RailwayTraining Cen-tre at Derbyfor WilliamTeague Ever-all. But the story of how I came to be there goes back to before the war when I was one of four engineers at the British Steelwork Association.

BSA was set up to rationalise steelwork design. There were 40 or 50 steel fabrication firms who all used to do separate designs and then bid against each other for each

contract. Centralising the design

office meant that only one design was needed and the fabricators could all bid on that. Everall had been in India as engineer for the North Eastern Railway and was full of ideas for sectional bridges and trestling. He said to the War Office: 'Youshould get some trestling going, and some bridging.' He approached my boss at BSAfor some design work and was told: 'Beckett will do it.'

Later on I was anxiousto get some site experience. I had got my degree part time and wanted to join the Civils.The war started and I volun-teered to join the Navy. I was sent home and told to wait. At the end of

1940I was sent to NapierBarracks,

Folkestone,then via the OfficerCadet Training Unit at Aldershot I ended up at RTCDerbyunder Everall,who was

f i

..

:1

I

L I

~

~I 8

-'chief bridging instructor'. Everall went to the War Office once a week. We worked on his temporary bridg-ing systems. He was talkbridg-ing of spans of 400 feet. This was to carry two 100 ton locos, it was very heavy stuff.

Wewere producing parts invento-ries for different spans in six-inch increments. Later the system was used to put a bridge over the Seine in a week and to build three 300foot spans at Deventer. After one of his visits to the WarOfficeEverall came back with a sketch elevation show-ing a flat beach with a % mile long jetty including 60 or 70jack up plat-forms. 'There you are Beckett. You're a bit of a yachtsman, think of some-thing better than that!'

I made a sketch for the outline of a shallow draught pontoon bridge. Myargument was that you push it in at high tide. At this time it had to be seaworthy, there was no plan for a breakwater. We made a tin plate

model. RSM Horner helped, he was a

good artisan. We also made a

wooden box to put it in and sur-rounded it by felt packing. Everall could not carry it in the open under his arm, you had to be careful about security.

The next week he took it to the War Office.When he got it out of the

box all the felt had stuck to the paint. Back at Derby he told me

'Beckett, they liked it. They want six spans and they need the drawings by the end of the week.' Braithwaites got the contract and the prototype was assembled up at Cairnhead on the north west coast of Scotland.

Allan Beckett in wartime, and today as a consultant

Roughweather was needed to test it. Ajack up platform was ordered from Lobnitz & Co. The other designs being tested there were Hamilton's Swiss Roll floating roadway, long timber sleepers encased in canvas with hinged canvas sides, and lorys Hughes' design for concrete pon-toons topped by a tower with pairs of projecting arms into which a barge bridge span could be pinned.

In due course I had a call from Bruce White. 'You're on the night train. They've had some bad weather and your bridge is breaking up.' I went up and Lt Col Sainsbury drove me to the site. He would not let on what the problem was but when we got within a mile ofthe sea you could hear, above the wind, a terrible screaming noise of metal on metal. It was like a bucket dredger at work. The Swiss Roll was washed away

and poor old Hughes was not doing too well. Sand had scoured away under the piers. But apart from the noise there was virtually no damage to ours.

Later on during trials in the Bris-tol Channel I was Bris-told: 'Why don't your build a BaileyBridge?' I wrote a letter to the chiefs of staff meeting at Cairnhead saying that something special was needed because you had to run tanks on and off it.

Steer Webster at Tn5 said you had to have a junction to cope with the tide and so we made a telescopic

span. At the chiefs of staff visit they said 'we want six miles of this'. Braithwaitesmade jigs and these were distributed to all the other manufacturers. In the end we had 10 miles of roadway on order.

The original concept with no breakwater was decided to be no

NCEMULBERRYHARBOURSUPPLEMENT 9 JUNE1994

(9)

,.

I I

)

t,

I

I

I

through a submerged pipe and

released to form a screen of bubbles. This proved to be impractical, and was replaced by the Navy'smain pro-ject, a form of boom, at first flexible then later taking the form of a series of linked steel boxes, so propor-tioned as to disrupt the natural period of the wave. This was to

become Bombardon.

Plans for an artificial harbour which were being drawn up behind the scenes by Bruce White's engi-neers and naval personnel were known only to a few, the planners themselves, some officers at Com-bined Operations headquarters and Lord Mountbatten.

The top brass, with the probable exception of Churchill, had still to be convinced. This was done by a means of an elementary scientific demon-stration on the Queen Mary which was taking a distinguished party, including the Prime Minister and the British Chiefs of Staffs across the Atlantic to Quebec in August 1943 where Overlord, as the invasion was known, was to be examined by the

J

r ..., . ..

'

.. l.! , j i

good and Bruce White thought of

using concrete caissons, the

Phoenix units. But the Navy said these would be no good and insisted on floating breakwaters, the Bom-bardons. These had to be made of Vi inch steel plate. The Navygot prior-ity of dry docks to build them in. And their next priority was Viinch steel plate.

Next they said: 'We can't get enough steel plate, you can use con-crete.' I said we can't because of the rocks on the shore and so they took the design to Mouchel.It was agreed that we would use concrete for the pontoons, Beetles, but it was only 1Viinches thick. It had to be thin to get the draught. They snapped the bridges on at Marchwood before they were cured and you could almost put your foot through the concrete. They had to be towed to

where the Phoenix units were

assembled at Selsey. But the first two tows didn't arrive. I said to Bruce White: 'Shall I go on a tow?'

We didn't go very fast so I could lift the hatches and see in each of the six compartments. We came out of Spithead and turned left. There was a gate in the submarine netting. the first tow had to wait around while the tug opened the gate. I noticed it was not going through straight and got tangled up. We got through OKbut they had holed one of the pontoons in the first tow. It promptly sank and soon they had all gone to the bottom.

I had no confidence in the

con-crete pontoons, we put timber

bau1ksround them to protect them. Even so I think there must be three miles of concrete pontoon bridging at the bottom of the Chaunel. I wrote an instruction manual but it had to be in guarded terms. The

I

British and Americans, led by Presi-dent Roosevelt.

Guy Hartcup writes: "A selection of senior officers was assembled in one of the ship's luxurious bath-rooms where a demonstration was given by Professor JD Bernal, the eminent physicist and one of Mount-batten's scientific advisers. Standing on a lavatory seat, Admiral Sir Dud-ley Pound, First Sea Lord, invited his colleagues to imagine the shallow end of the bath as a beachhead. Bernal now floated, with the assis-tance of Lt-Cdr DA Grant, a fleet of 20 ships made of newspaper.

"Grant was then requested to

make waves with the aid of a back-brush. The fleet sank. A Mae West Iifebelt was then inflated and floated in the bath so as to represent a har-bour. The fleet of paper boats was then placed inside it. Once more

Grant applied his brush vigorously to

create waves, but this time they failed to sink the fleet. By such sim-ple means were the senior officers convinced of the importance of shel-tered water."

security was very well done by counter rumours such as: 'We were building a bridge across the Chan-nel, but don't tell anyone.' The Ger-mans knew we wouldn't go ashore on a rock strewn beach.

When it came to D-DayI said I'd like to go. There were a lot of ques-tions about just how the floating jetty would be used. A lot of senior people did not know anything about it at all and there had been very lit-tle training. The Americans showed us how to tow them. On the eve of D-Daysix US motor towing launches came looking for something to pull. I went over on the first tow.

I was sent to help the Americans on D+5 and was alarmed to see that they had used a mix of the Mk 1 and Mk2 bridging equipment. The Mk 1 was rated to carry 25 tons and the Mk 2, 40 tons. Originally the pier was designed for road transport, it wasn't realised until later that the LSTs could be docked onto it. Ells-berg (Cmdr Edward) said: 'We've done some calculations and we think we can get away with it.'

Ellsberg waved on a tank and it ran OKuntil it got to a bit of Mk 1. It speeded up and got though, andjust didn't sink the pontoon. All the top brass was lined up on the shore. They started running more tanks over it. I was torn between being pleased and wanting them to stop abusing the equipment.

Later on when the storm started I sat on the end of the Centurion and watched the waves knock the stuffing out of the Phoenixes. They were all brim full of water. The

waves were coming over the top and the walls failed by falling outwards. Afterwards I reported back.

My news was not good but at least it was objective."

9 JUNE1994NCEMULBERRYHARBOURSUPPLEMENT

TOP: Bottom shutter for a Phoenix unit being built in a floating

dock.

CENTRE:Base of a Phoenix ready for a float out from a dry dock. BOTTOM:One of McAlpine's caissons ready for towing to the assembly point for D-Day.

(10)

-I

The concept having been

approved, all that still required to be

done was to get the harbour

designed and built. That was simple enough except that the invasion date was less than nine months away and of these only about seven were actu-ally available for the work once vari-ous preliminaries had been tackled. The problem was simplified, on the British side at least, because the core of a command structure already existed under which a good deal of preparatory experimental and devel-opment work had been done.

It was not a simple and direct one, however. For historic reasons, the War Office (as it then was) was responsible for port construction and operation while the then Admi-ralty was responsible for shipping inside the harbour. This followed the long established practice that har-bours were constructed by civil engi-neers and ships were sailed by seamen. That sensible enough divi-sion of labour was to lead to some dif-ficulties later on.

This was where Bruce White came in. As early as 1941,he had been put in charge of a new division of the War Office called Transportation Five (Tn5). By late 1943,Tn5 already had

considerable experience both of

building new ports and operating older ones. By then, too, White had established his register of civil engi-neers, now some 150 strong. These were 'either in Tn5 or were posted to field units of the Royal Engineers. They were essentially civilians in uniform, and saw themselves as civil engineers rather than as soldiers.

Although the final decision on the nature of Mulberry was not taken until the late summer of 1943, White had known where the landings were to take place since June of that year. So he had been able to come to some conclusions about where the har-bour was to be and, to some extent at least what it was to be like. In ordi-nary harbour works in

everydaycivil-ian life, the first requisite is adequate site information.But in

this case the site was in enemy hands and site surveys were likely to be hurried and hazardous if they could be carried out at all.

In his1990Dickenson Memorial Lecture to the Newcomen Society, professor Sir Alan Harris quotes the naval officer in charge of construct-ing the breakwater, John Jellett (later a president of ICE), as saying: "... a letter had come to the Admi-ralty from a Dutch engineer working in Portuguese West Africa, saying that after the Dieppe fiasco it was clear that we should be unable to

capture a port on the continent

-

we

should therefore build one. He

thought that the best location would be on the Calvados reef at Arro-manches."

If this could be worked out from West Africa by a man who appeared to have considerable local knowl-edge, it is perhaps surprising that it

I

1

I

'1 .

I

,

i

,

10

"One

morning

four orfive of my close

colleagues were missing from their desks"

Georg!! Crabb was a designer with LG Mouchel & Partners during the war records his memories of Mul-berry.

"I was an RC design engineer in

1943with LG Mouchel. It was

cer-tainly not the best of times, with

many things happening

-

most of

them unpleasant.

Mouchel were then re-occupying their old offices, 4th to 7th floors at 36/38 Victoria Street, Westminster, where they had been since 1901, except for evacuation to three large houses in Sutton, Surrey. The Victo-ria Street building was an ancient 'brick and timber' block of probably mid-Victorian vintage. Life was far from comfortable there, 000 floors and gas fires, but that was the wayit was in the 1930s/40s.

It was in these conditions that the Phoenix caissons, crept up on us. One morning four or five of my close colleagues were missing from their desks. This happened for two or three days. It was most odd that they could all go sick at the same time. Curiosity then did obtain an explanation that they were working 'round the comer' at the War Office and that it should not be talked about.

They were busy with Phoenix. Mouchel became involved no doubt because of their earlier projects with concrete floating structures in

the First World War. In 1918

Mouchel under CRJ Wood had

designed a concrete ship of 1150 tons and 205 feet in length which

successfully traded under the name

SS Armistice during the last few

months of the war and up to the late 1930s between Britain and the West

Coast of Africa. Mouchel also

designed, and saw built, concrete tugboats and barges, so the firm was probably the obvious choice to be involved. Part of the project was to provide some six miles of breakwa-ter formed by large sunken concrete caissons, and floating piers with unloading heads. The energy and speed involved is illustrated by CRJ Wood'snote that the team 'took off' the whole tonnage of reinforcement by diameter for all six types of cais-son in two days.

Another engineer, well known to me when he and I were with Sir Owen Williams prewar, was Iorys Hughes. It was he who translated Sir

Owen's concept for the concrete

-.;1

j

arch roof of the Empire Pool Wemb-ley into a working possibility while I and another member of staff pro-duced the drawings.

By1942he had left Sir Owenand

had an office in Victoria Street. His hobby was sailing and boat design (he won the Jubilee Cup in 1935 in

his home town Bangor). Here,

therefore was a perfect combination

of civil engineer and marine

designer who could play his part in the Mulberry venture. Hughes car-ried out the survey of suitable sites on the coast or in estuaries where beach profiles and tide fluctuation were suitable for the construction of the caissons.

I also understand he was involved in floating pierheads and the towing design for the units. I have often felt his contribution has not received sufficient credit."

OfficialAdmiraltyartist Sir Muirhead Bone's drawing of Phoenix caisson construction.

(11)

-

--

-1

I

I

ABOVE: Concrete Beetle floats being launched by a specially built gantry crane.

TOP: Barrows were used by several contractors to feed concrete into walls for the huge Phoenix caissons.

9 JUNE1994NCEMULBERRYHARBOURSUPPLEMENT

"Wewereworkinginan

atmosphere

ofincredible

tension"

Herbert Cruickshank, then plant and labour manager for Bovis, was

rungin September1943byhis

man-aging director Paul Gilbert and told to be in Portsmouth at 9am the next day to organise some building work. Cruickshank was 34 at the time and a renowned "starter upper" of pro-jects which stood him in good stead throughout his career. When he retired in 1971 he was chairman of Bovis.

"Paul Gilbert was the old fashioned, purple complexioned sort of manag-ing director. If he said to be there at 9am, there was no question that I wouldn't be.

When I arrived there were 50 or

60 other contractors standing

around outside the gate all asking each other what was goingon. Even-tually we were shown into a large room by a rating where we sat and

waited. Suddenly another rating

popped his head round the door. 'Please stand for the Admiral,' he said.

Weall did, and for Paul Gilbert to stand for anyone was amazing. The Admiral stalked in, in full dress

Herbert Cruickshank

was not thought ofby the Germans as well. But perhaps their strategic pre-occupations were distorted by the fact that they could see southern England from the vicinity of Calais and never expected the Allies to take E a long sea crossing when they could ii! take a short one instead.

!; Harris goes on: "Wellit was not on

~

the Calvados reef, but the reef

pro-~

vided valuable shelter. The reef is to

~ the north-east of the east end of Mul-g, berry at Asnellesj it dries out some .§ five feet at MLWS,when it can be reached from the shore by wading. The charts show a gully running south-east of the Calvados reef. The coast around Arromanches, from

regalia

-

hat, braid, everything. He

looked at us and said: 'Gentlemen, I have been told that you are to come into My Dockyard to carry out important building work. I don't like it. I don't want you in

MyDock-yard but I am told your work is

important. I expect you to behave in a responsible manner.' And off he went. Gilbert turned to me and said: 'Wonderful.'

He had recognised his twin. We were then sent back to our offices with drawings provided by the MoDwhich we thought were of barges. There was nothing difficult about them, they were concrete

structures, just massive and

unusual ones. So I set about mobil-ising for the work and got the struc-tures started in the drydock with the help of agent John Harvey.Noth-ing frightened him, not even Gilbert and not this job, though we were working in an atmosphere of incred-ible tension. I remember that very clearly.

They kept the pressure on all the contractors by telling us that if we

weren't up to programme they

would bring in the Americans."

Cap Manvieux to Asnelles, was as good a place for Mulberry as any. where in the Baie de la Seine. The shallow water inside the reef was ideal for the Gooseberry; the gully gave access to moderate draught coasters."

So the landing area provided a suitable site for Mulberry B. But not much was known about it from the

harbour planners' point of view.

Some information was available from pre-war charts and aerial

pho-tographs, and a number of soundings had been taken before D-Day,and this formed the basis of the layout which was adopted. This information was not sufficiently reliable,

(12)

1--

,...

I Pierhea'ackUp

unit

sh

-I hinged precast co~crete teRder unitS.

ever,for a final plan of the harbour to be devised and a close echo survey was made between D+ I and D+3 as soon as the site was in British hands. In general terms, the layout of the harbour was influenced by the fact that the blockships could get to the site under their own steam and some of them could cross the Channel as part of the great invading armada on D-Dayitself. The more they could be used, the less would be the need for the concrete caissons which had to be towed across. But there were physical limits to the use of block-ships, even apart from their avail-ability. The large tidal range (up to 26 feet) limited their use to rela-tively shallow waters. In depths suffi-cient to shelter coasters and supply ships, breakwaters using caissons were necessary.

In the end, the proportions in which these two elements were used depended on the availability of

ship-ping for towing and construction purposes.

The layout was influencedby a number of other considerations. Thesewere listed by John Jellet in his paper:TM layout assembly,and behaviour of the breakwaters at

~I 12

Arrornanches Harbour (Mulberry B), in the ICE publication TM civil engineer in war (1948). He writes:

"(1) Meteorological information showed that the greatest protection

was needed from north-west to

north-north-west, that the

Cher-bourg peninsula would give

consider-able protection from west to

north-west, and that the Le Havre peninsula and, at closer range, the Calvados shoal, would give similar protection from the north-east. Pro-longed bad weather from the due north was unlikely and, in fact, was never encountered.

"(2) A tidal rise above LWST

vary-ing from 18 feet at neap tides to 24 feet at ordinary spring tides and as much as 26 feet at extraordinary springs was predicted. The existence of a strong coastwise current, west-wards on the ebb and eastwest-wards on the flood, with a stand of three hours at high water was also known. The strength of that current made it essential that the entrances should be so faced that ships would enter or leave on a course parallel to its direc-tion and not across it.

. "(3) It was necessary to give com-plete protection to the pierheads,

the shore exits from which were

almost rigidly determined by the lay-out of the roads serving the town of Arromanches, and which required to be in a least depth of 18 feet for use by coasters at all times. These

condi-tions defined the position of the

piers to within narrow limits. "(4) The requirement to provide, if possible, anchorages for Liberty ships inside the harbour

necessi-tated the enclosure within the

breakwaters of a sufficient area hav-ing a least depth of 24 feet at LWST. "(5) A blockship of 37 feet overall depth (the largest provided) placed in a depth of two fathoms at LWST would be submerged by one foot on a 26-foot tide. A ship of 25 feet overall depth (the smallest provided) would have to be placed in zero depth at LWSTto be in similar conditions. The

dimension taken to represent overall depth was the height from the keel to the highest continuous deck, and is a conservative one, making no allowance for bulwarks and super-structure, which have considerable value as part of the breakwater.

"(6) The overall depth of the largest caisson provided was 60 feet (it is doubtful if any larger unit could

have been contemplated as a towing commitment), which would be com-pletely submerged by a 26-foottide if

placedin a depthatLWSTexceeding

34 feet, and the objection to placing the units in such excessive depths lay in the possibility of disturbed conditions inside the harbour if bad weather should coincide with high spring tides. On the other hand, from the information available, there was a doubt whether the spacing of the seabed contours would allow the requirement (4) above to be met."

The main breakwaters at both harbours consisted of large rein-forced concrete caissons sunk to the

seabed and blockships ballasted

with concrete and scuttled by explo-sives. The caissons were mostly about 200 feet long by just over 53 feet beam with an overall height of up to 60 feet. Some were smaller with the smallest being 174 feet in length.

Seven firms or groups of consult-ing engineers were givenresponsibil-ity for supervising the construction of the caissons. These were Oscar Faber, Sir Alexander Gibb & Part-ners, Sir Cyril Kirkpatrick, Rendel Palmer & Tritton, WT Halcrow &

(13)

"Wewatchedthisthing,

40

feet high,launchitselfoutinto

SouthamptonWaterunderits ownsteam"

I

I

1

I

l

r

I

Freddie Downing, who was Bovis Construction's assistant managing director when he retired, had an exciting time with Mulberry -learn-ing to build on water and dodg-learn-ing Doodlebugs.He was 30 in 1943. "When I started off in Portsmouth the fIrst of our structures were going up in drydock. They were being built to 25 feet in the dry, then flooded and floated out to a wet dock. That's where I took possession of these boats, as we called them.

I then had to put on another 30 feet while they were floating and unstable. Bovis pumped the con-crete in the dry dock. On the water we used hundreds of barrow run-ners. Because the caisson was float-ing we had to be able to take the concrete to where it was needed to keep the thing stable, so the barrows were better for that. The system was not foolproof though.

I was moved on to some units being constructed in Southampton where Bovis was helping Pauling out. We took over with 15 feet to go. When we got there the units were

tied up alongside a jetty on

Southampton Water, exposed to the sea. Southampton Water has a 17-foot tide, twice a day, so we were up and down all the time.

Bovis' best foreman, a chap called Page, decided I think to show how quickly he could get concrete laid on

j

t

Partners, Wolfe Barry Robert White & Partners and a group including Coode, Mitchell, Vaughan-Lee and Gwyther.

Since the caissons were to be floated out, it would have been desir-able for them to have been built in dry docks, but the Admiraltyhad ear-marked these for the use of shipping and the Bombardons. So alternative sites had to be found. Graving docks were made available at Tilbury, Goole and Middlesborough and the vast East India and Surrey Commer-cial Docks were used. At the latter two, the docks were drained for the fIrst time since they were con-structed more than a century before leading to fears that the walls might

collapse because of unbalanced

water pressure. Such a collapse did indeed occur reducing the capacity of the docks as building sites.

Other caissons were constructed on beaches near Portsmouth and launched down slipways. A number of sites were also chosen in the Thames estuary where the caissons were constructed in temporary, exca-vated basins and floated out when partially complete.

Altogether 213 units of various

his side of the boat. He did it too

well, because suddenly there was a .l1J

lot of shouting and the caisson I

started to list to one side, far enough to let water in throughthe scaffold- iI

ing holes. A plumber, Dudley

Wheeler, shot down inside the unit to open up some penstock valves on the other side in an attempt to right it (he won a BEM for his bravery). This straightened the unit up, but too late and water was still pouring in. We stood on the dock side and saw it sink to the bottom.

With a 17-foot tide, the bottom

was sharply shelving and we

watched this thing, 40 feet high,

launch itself out into Southampton Freddie Downing

Water under its own steam. When it came to rest, the water level was at the top of the shuttering and all you could see were bits of scaffolding tube sticking up out of the sea.

Just then our managing director Paul Gilbert, a chap who on a good day resembled an apopleptic admi-ral, turned up.

'God Downing!' he bellowed 'What'sthat?' I'll alwaysremember hisface goingall differentcolours.

I explained that to maintain

progress we would send the men out in a boat at low tide, and get rid of the ruined concrete then.

The problem was how to refloat the structure. Jack Ward, our agent bless him, had an inspiration. He asked Pauling exactly what size

--their scaffolding holes were and designed some timber wedges that were hammered in by navy divers to make the boat watertight. We could then pump the water out using some borrowed hoses from the navy dock-yard. It worked and we were only two days behind.

When we started building Mul-berry caissons in the East India Docks in London, I was moved up there for the doubtful pleasure of building them with a lot of jockeys drafted into the Pioneer Corps. But it was a short stay. The VIs were coming over then and one came down inside a unit and blew it up. But its reinforced concrete con-tained the blast a bit and limited

damage to the rest of the area. Con-struction was moved up to Liverpool then.

I used to drive over to the docks from my home in West London in a chap called Sam Bond's car. I just got through the front door one night when a Doodlebug scored a direct hit on it. The car was smashed to smithereens, and the front wall of our house was destroyed.

My wife was in hospital for two weeks, and I had to take a day off work to have the timber splinters removed from my chest where I'd been blasted through a door. Then I had to look for somewhere else for us to live. But we were all used to that by then."

PrototypeMK1 Whalejetty tested with a 20° twistin December1942.

9 JUNE 1994 NCE MULBERRY HARBOUR SUPPLEMENT 13

(14)

sizes were constructed. Ofthese, 147

were needed before D-Day,the

remainder being required by the autumn of 1944, 40 of these being

strengthened units designed to

extend the life of the harbour. These were designed by a War Office team augmented by designers recruited from a number of consulting engi-neers and other sources.

The essence ofthe caisson design, apart from their being sufficiently robust for their allotted task, was simplicity. They were to be plain and symmetrical, without splays or gus-sets at angles. Reinforcing was to consist almost entirely of straight

bars almost always without end

hooks. Large openings were to be left

in cross walls, partly to reduce weight and partly to keep the centre of gravity low. In order to facilitate towing, swim ends were provided. Some primitive provision was made for crew quarters and gun mount-ings. An additional design complica-tion was that design, construccomplica-tion

and experimentation on flotation

and other problems were going on at the same time. Any modifications arising from the experiments had to be incorporated during construction. The two dozen contractors chose their own methods of construction, depending on the facilities available on site and the plant, shuttering and other materials obtainable as well as the supply of labour, much of which was unskilled and inexperienced in construction work. The total number of workers involved in constructing

the caissonswasaround20,000- not

counting those engaged in work off site. Casting of the units themselves began in December 1943 and was completed in 150days. The fIrst cais-son arrived offArromanches on D+ 1.

Within the shelter of the breakwa-ters and the blockships,the

har-bours were to consist of a number of moorings for Liberty ships and coast-ers, and piers for unloading cargo and personnel. Some supplies, espe-cially from the Liberty ships, would be unloaded on to the beaches by means of DUKWsand ferries. Tradi-tional piers would have taken too long to install and because of the tidal range and the gentle slope of the beach would have been too lengthy. There were to be three piers at Mulberry A and four at Mulberry B. So the pierheads had to rise and fall with the tides and allow coasters

Precast concrete Beetle unit being assembled by Wates.

to unload at any state of the tide, directly and rapidly on to vehicles. The shorearms were floating road-ways along which vehicles could quickly make their way to beach.

While the breakwaters were cru-cial to form a sheltered haven where none had been before, the effective-ness of the harbours depended to a very large extent on the piers. For maximum utility, these had to ride with the tides, as demanded by Churchill.

To meet this demand, Bruce

White drew on the design of a type of dredger which had been devised by Lobnitz & Co of Renfrew for the

extraction of minerals. It consisted of a large rectangular pontoon with sturdy load-bearing piles at each cor-ner equipped with spuds at their feet. When the pontoon was in its required position, the piles were dropped to the seabed and the pon-toon wasjacked up so that it was car-ried by the piles. The pontoon then provided a stable working platform. An assembly of these became the pierheads. As built, they were 200 feet long by 60 feet wide and 10 feet deep and had crew accommodation, and a suitable number were posi-tioned in line at the head of each pier.

"Assoon as the lock entrances were secure the

construction of the eight massive units started."

James Pope started working for

Mowlem in autumn 1943 as a junior engineer building petrol barges at London's West India Docks before he joined the Mulberry project.

"After only a few weeks, the whole

staff was transferred to Surrey

Dockswhere, amid great excitement and urgency, a contract was starting which was to result in the construc-tion of eight of the Mulberry Har-bour Phoenix units.

There was a rapid increase in the numbers of the staff, many members arriving from airfIeld construction sites where that work was beginning

to diminish.

We took over a conveniently vacant Port of London Authority office.

As our units were to be built in the SouthDocka lot ofpreliminary work was required; the two lock

14

entrances to the dock had to be made secure, one by means of a mass concrete dam and the other by heavy timbering.

While this work was proceeding and the batching plant for the con-crete was being prepared, an end-less stream of tipper lorries was arriving with hard core from the

bombed areas of the east end of Lon-don.

This formed a shelf round the bot-tom of the dock.

As soon as the lock entrances were secure the hardcore was lev-elled by bulldozers to complete the shelf, and the construction of the eight massive units started.

The timetable was extremely

tight and the highest priority was given to the supply of all necessary materials. Steel reinforcement was the vital component.

One remembers the frantic

tele-James Pope

phone calls to the steel mills and the anxiety as the progress of the trucks carrying the steel on the railway was tracked through the country.

The engineer responsible for the

jt!',';iJ

__I

reinforcement, AR Harris, main-tained a large chart several yards longon onewall ofthe officewhere the precise state of the stock of every single bar was recorded."

(15)

1

l

At Mulberry B, one pierhead was adapted so that landing craft could unload directly on to it by dropping their ramps on to special pontoons. Apart from speeding up unloading, this was particularly useful since it avoided the need for landing craft to beach themselves on shore with the likelihood of damage to their under-sides.

The shorearms, which were about % mile long, were floating roadways (known as Whale) consisting of girder bridges of 80 feet in span with a 10foot wide carriageway supported on floating pontoons. The girders were carried on spherical bearings which allowed for the twisting move-ment caused by wave action and live loads. Their principal designer was Lt Col Everall, but his assistant, Ml.\iorAllan Beckett, was responsible for much of the innovative detail. Everaillater described Beckett's role in the following generous words "Beckett, who had followed the scheme right from its inception to its use on the beaches of Normandy on D-Day,was the outstanding engineer who was primarily responsible for the success of the bridge and was one of the key men responsible for the success of the Mulberry Harbour. He was responsible for most of the

unusual features

...

and they spoke

for themselves!"

The pontoons (code named Beetle because of their shape) were 42 feet long by 15feet beam and 8 feet deep. Some were constructed of steel plate and, because of the prevailing steel shortage, some were made of precast concrete with a skin thickness of 1~ inches. Not surprisingly, the con-crete pontoons proved to be the most

fragile.

By January 1944,the number of pierheads required had been

increased to 23, a few of which were spares. The total length of floating roadways was increased from six to

ten miles, three of which were

spares. This needed 120 spans, each 80 feet long, and eight shore ramps. Some 670 pontoons were needed, of which 470 were of concrete and the rest of steel. The total steel require-ment for the pierheads was 60,000 tons, and the shorearms needed 30,000tons of steel and concrete.

Prefabrication of the pierheads was spread among 300 firms and the roadways among 250. In all, the work required a labour force of 15,000. Some of these companies were of high quality but some were not, espe-cially among the concrete firms, some of whom were more used to supplying fence posts than the water tight panels for the pontoons.

The pierheads were

manufac-tured in Scotland and Wales, and whenever possible were of welded construction to save steel. Owing to the shortage of welders, much of the work was done by people who had never seen a welding torch let alone handled one. Not unnaturally, con-struction of the piers fell behind

t.

I

"Whenyoumentioned"Phoenix"

yougot

absolutepriority."

Bob Nivison arrived at Barking Creekon a bleak dayin September 1943 at the start of contractor Arthur Monk & Co's contribution to Mulberry.

'''Report to Barking Creek' I'll

always remember that. I was the first there and told: 'The job code name is Phoenix. You will be site engineer.'

When the war started I was at Brighton Technical Collegestudying for a London University degree in engineering. I was 18 and was told my call-up would be delayed,

provid-ing that the lecturers confirmed that I was working hard.

I got first class honours then went before the Joint Recruiting Board. They said I was ideal for the REs. After passing the medical I waited at home for orders. Three months past and none came, it was embarrassing.

Then in early '42 I got a letter to say there is an urgent need for expe-rienced engineers on specific pro-jects. 'Report to Arthur Monk & Co at Warrington' it said. I was sent off to the south coast and was there until the end of the summer working on various defence jobs.

The order came for the move up to east London and I remember it was a very bleak day when I got to Barking Creek. We did not know what we were building but just called it a great big concrete boat. Our job was to build the bottom parts then the units were floated out and towed up the Thames to the East India Docks where a separate Monk team built the superstruc-tures. We sensed it was very impor-tant from the high powered naval

schedule, to the intense annoyance of the Americans who were some-what impatient of some-what they took to be British dilatoryness. Neverthe-less, by mid-May 1994, 14 pierheads were ready and all but one was ready by the end of June.

Part of the concept of an artificial harbour was an outer protecting arc consisting of a floating barrage. The problem was to design one which could deflect wave energy and also provide reasonably sheltered water without being the equivalent in size of a ship or, as it would have beep, a number of ships line astern and fixed

in position.

The first model tried out had flex-ible sides. It helped to prove, to some extent at least, the underlying theo-ries on which the floating barrages were designed. They also suggested that they could, in fact, provide calm water as efficiently as fixed

breakwa-9 JUNE 1994 NCE MULBERRY HARBOUR SUPPLEMENT

Bob Nivison

people

-

with ring after ring on their arms- whokept comingto visitthe site.

First of all we had to build a basin with an earth dam keeping out the river. A thin layer of concrete went down as blinding and then we used light timber boarding as a soffit shutter so they would lift off later on.

Getting men and materials was

no problem

-

timber, sand gravel,

cement and steel. It was always the same when you rang up the Ministry of Labour or Ministry of Supply. When you mentioned "Phoenix" you got absolute priority.

Monk, like the other contractors, was selected by the Ministry of Sup-ply rather than bidding for the work, there was no time for that. Wewere paid cost plus a percentage. No physical measure of the work was ever done but we had to keep very accurate records and all returns were made in triplicate.

One of my most important jobs

ters. Essentially, it consisted of a rubberised canvas tube supported on a reinforced concrete slab which served as a keel. In full size, each unit would have been 200 feet long by 12 feet beam and 16feet 6 inches draught. Three were launched in late 1943, but the design was abandoned because of the fragility of the canvas tubes.

Thinking turned to a rigid boom and tenth scale models of one such had been tested in June 1943. This was to become Bombardon. When it was decided at Quebec that

Bombar-don was the preferred choice,

responsibility for designing and pro-ducing it was given to the Admiralty. Even at that late date, the theories had still to be fully developed and further model tests carried out.

The requirements laid down by the Combined Chiefs of Staff were as follows (according to the paper in

was making sure the concrete qual-ity was OK.There was a lot of rein-forcement and we had to get good compaction as well. Joints were waterstopped but if there were any porous parts in the walls the water would get into our boats. The con-crete was all pumped which led to arguments between me and the gen-eral foreman, Les Brookes, as to whether it was too stiff for the pump. I learned a lot from Les.

Officially the hours were 8am to 6pm but if there was a big pour on we had to stay late. Wegot a little bit of overtime but it didn't reflect what we were doing. I lived in digs in East Ham and didn't have much spare time to do anything except have a pint in the local and go to bed. On occasions we had to work night shifts as well to keep up to time. Workingin the dark was not a prob-lem as we had plenty offloodlighting - but it had to go off if there was an air raid.

First reaction of everyone to the units was: 'Will it float or will it sink?' My boss said simply: 'If it sinks you'll probably be drafted in the army pretty quick!'

Fortunately it all went very well. Wehad to work through the night to dig out the dam."

When Phoenix work was com-pleted Nivison moved on to other war work building pipelines and tanks around Lincolnshire and York-shire airfields for FIOOfog dispersal systems. He stayed with Monk,

becoming director in charge of

north west Scotland, and now lives in retirement at Wilmslow. Monk was absorbed into the Trafalgar

House Group.

The civil engineer in war):

"(1) Sufficiently mobile to be towed across the Channel and pro-vide some sheltered water by D-Day

+4;

"(2) To be completed in all respects by D-Day + 14;

"(3) To be strong enough to with-stand winds up to, and including force6;

"(4) To be capable of being moored in water deep enough to pro-vide shelter for Liberty ships;

"(5) To be ready in all respects by

May 1944."

Although Bombardon was

designed to cope with a wind force 6, it was known that stronger winds are experienced in the Channel. It was thought, however, that such strong winds were unlikely in June and July. In any case, had Bombardon been given a more severe specification, there would neither have been time

15

(16)

-'I

! ,~

Bassett-Lowke's fully assembled model of the Whale floating

platform and pierhead with a docked ship.

1

nor materials for it to have been

designed and constructed in time for the invasion.

The overall dimensions adopted were 200 feet long by 25 feet beam and 25 feet approximately deep with a draught of 19 feet. The structure, which was more or less in the shape of a Maltese Cross in section, was

built of steel plates and angles

bolted together. Choice of bolted

connections was forced on the

designers by the wartime shortage of

welders and riveters and was one which they would have preferred to have avoided.

When launched, the bottom and

I

side arms were filled with water to

provide stability and the mass

needed to combat wave action. In place, the Bombardons were moored in pairs between buoys, and the lay-out adopted was two parallel lines, 800 feet apart. This arrangement was expected to reduce the wave height by some 70%and the wave energy by 90%.

The fIrst Bombardon units were towed out in the invasion fleet on D-Dayand the fIrst stretch offloating breakwater was in place by D+2. A single line breakwater, each of these a mile long and comprising 24 units, had been provided at both harbours

He ismodestabouthisown

efforts.Theywerepivotal.

I

~ .

.

If Bruce White was not the origina-tor of Mulberry, he was the engi-neering driving force behind it. He was a well known civil engineer and had been a Major in the RoyalEngi-neers in the First WorldWar.In 1939 he was in charge of transportation and the building of new harbours at Faslane and Cairn Ryan in Scotland. But after Dunkirk the need to return to Europe by invasion was never far from his mind. White quickly realised that this needed the artillcial harbours which even-tually became Mulberry.

He had asked why it was that ports were the responsibility of sol-diers and not the Navy.This was a question that the Navy was also inclined to ask, with some asperity.

It was neatly answered by Churchill:"... seamen go to sea in

ships and it is in their absence that the landsmen build harbours and refuges to which are brought back the fruits of their services".

Relations between the services were sometimes strained and White refers to one high level meeting,

~I

16

--Sir Bruce White

fromwhich the Navyemerged

victo-rious, as one of the biggest battles of the war. His own account of the design and construction of the

har-bours is unduly restrained and,

while he praises others generously, he is modest about his own efforts. They were pivotal. He saw clearly what was needed, and he saw that it

wasdone.

N

r

(17)

"It washazardous

work,andschedulesweredemanding."

Foreman Archie Borthwick worked for Laings and recalled his experi-ences ofMulberry in the firm's news-paper Tham Spirit during the 1980s. He was sent to work on Phoenix in October 1943.

I

"I had arrived at Portsmouth on the

.

Friday morning and our welfare

offi-cer Jimmy Ellis with his list of 'dig-.gings' soon had me accommodated, land on the Saturday morning I was able to begin at the beginning: ie look around the dockyard and the .area of the site, and formulate a few

ideas.

. The dockyard drydock area, was

approximately 1000 feet long by some 120 feet wide, and it was .arranged that Laing and another .contractor, Bovis, would share the drydock, with each contractor occu-.pying half the available area.

. There was a difference however

as one end had been bomb damaged,

by D+ 7. The Navy had not been lag-gardly. They were, however, moored

in rather deeper water than had been intended. At that depth, the waves were reduced in height by only 50% and the wave energy by 75%.

Although that was less than expected, it appeared adequate at first.

The Bombardons were to be

and therefore there was a matter to

be discussed

-

which company

would occupy which half?

Tocut a long story short, our area manager, WMJohnson called heads to a tossed coin and by calling incor-rectly, consigned the Laing opera-tions to the damaged end.

With the keel blocks removed, work commenced. First the existing floors had to be made to conform to a level surface with supplementary concrete being placed to augment the deficiencies.

This was followed with the place-ment of concrete blocks suitably spaced to provide drainage of water between, and this then was covered with heavycraft paper, to prevent any bonding between this support-ing base material, and the subse-quent pouring of the base of the Mulberry Harbour itself.

At this stage the construction of our first Mulberry Harbour caisson

severely tested, all too soon as it turned out, in the great storm of 19-23 June, shortly after they were put in place. Their effectiveness remains controversial, but the offi-cial report says:

"The floating breakwaters at both harbours withstood about 30hours of

this gale before serious damage occurred. This is impressive."

got under way. The first two units were identified as an AI type cais-son, as were all six units that were built in Portsmouth.

Drydock construction was super-vised by George Spain and Arthur Young.As I recall the Laing unit was well ahead in construction progress to its adjacent replica by Bovis.

While flooding the drydock we anxiously waited for movement of the massive caisson.

The unit broke awayfrom its iner-tia, and we were floating, and both units were taken to the wet dock, where the continuing work would now come under the supervision of Alan Greenhowand Tom Bending.

In the midst of our construction activities, I remember we were paid a visit by 'Monty' and I will never for-get the steely eyes and alert aware-ness of everything around. He was as extraordinary man, and I recall that the then Mr KirbyLaingwas present

That was perhaps making the best of a bad job. But, in fairness, it has to be said that the stresses imposed on the structures were at least eight times as great as the design stresses. It is not to be wondered at that the Bombardons failed.

Nevertheless, the authors of the paper on the Bombardons in The

civil engineer in war (Robert Lochnor, Oscar Faber and William Penney) remained convinced of the utility of the floating breakwater. They say: "The advantages of this sort of construction are many. In the normal case the cost of the floating type of harbour is of the order of one fifth to one twentieth of the fixed type. The area of sheltered water may be readily enlarged by the addi-tion ofunits and the mere re-siting of moorings. There is no interference with the local underwater currents and, in consequence, a complete

freedom from silting and scour. "A floating harbour may be

erected in a matter ofweeks whereas the fixed harbour is usually months

on the same day.

We experienced many difficulties because of the shortage of man-power and after some negotiation we were able to adopt a kind of coalition of trades.

In some instances labourers were upgraded to 'designated tradesmen', and they did a goodjob.

It was hazardous work at times, and schedules were demanding. The Laing units all passed their testing at sea, just off the Isle of Wight, and were submerged and pumped out to re-flotation without incident.

From Portsmouth I transferred to Belvedere Marshes where two more Al units were to be constructed.. These two units were first built to a. height of 14 feet 9 inches instead of the usual 28 feet.

They had to be towed up the River Thames, equipped with outriggers for stability, for completion at the Victoria &Albert Docks."

or even years in the erection phase of construction.

"A floating harbour may be

arranged to cater with a seasonal or temporary trade or requirement and the units then moved on or stored

awayin the off-season.In this way,a

temporary floating breakwater can be utilised to protect fixed harbour works during the erection phase.

"Although, when first suggested, the floating breakwater appeared as a rather startling innovation, and although the sceptics found many reasons before the trial why it could not work, yet, in fact, it did work and, inside its designed capacity, it suc-cessfully accomplished its allotted task in the invasion and liberation in Europe."

These are the brave words of men who were proud of the task which they were given and which they accomplished but, since the Bombar-dons were swept away and aban-doned less than a month after they were put in position, the jury must still be out.

9 JUNE1994NCEMULBERRYHARBOUR SUPPLEMENT 17

(18)

--Construction

in

France

S

ccess of the harbour depended

artly on the design and con-struction of the various units in Britain, partly on their successful transportation across the Channel, but ultimately on their successful installation at the site.

The officers chosen to undertake this task were mostly engineers with previous experience of

transporta-tion and port constructransporta-tion in wartime.

Overall commander at Mulberry B was a regular sapper, Brigadier AEM Walter, with Colonel GE Howarth as his deputy. Construction of the

breakwater was in the hands of Lieu-tenant-Colonel SKGilbert, an experi-enced engineer officer who has been described as "an eccentric in the

best tradition of the Corps of Royal Engineers". His naval opposite num-ber was Captain John Jellett.

Lieutenant-Colonel Raymond

Mais was to be in charge of con-structing the piers and pierheads. Mais had been a Territorial Army officer before the war and had served in various battle zones since 1939. He was said to possess that

charac-teristic which the French call elan. Within a fortnight of the landing, when the weather broke, he was to need it.

Mlijor Ronald Cowan, a Glasgow civil engineer, was in command of the Port Floating Equipment

Compa-nies which had been specially

recruited to assemble the compo-nents on site. Cowan takes up the

...

..

#JIfi

.,

18 NCEMULBERRYHARBOURSUPPLEMENT9JUNE1994

Cytaty

Powiązane dokumenty

1 – throughout history people have liked to live near water because of certain “classic values” of the water, such as the possibilities for transportation, recreation,

The purpose of the course: an introduction to general principles of choice of law process, an overview of main European and international instruments (so called the Hague conventions,

Nawet gdy sięgniemy po inne teksty, w których przejawia się interesująca nas figura, nie napotkamy napadów szaleństwa: „tamten niebieskie zwierzę u  wzgórza się

model tests vith the linearly and non-linearly moored tanker in high irregular head seas are shown. The comparison confirms that the

Throughout this research dialdehyde starches with different degrees o f oxidation have been studied to screen deviating product

Wkład tego uczonego w kształtowanie się amerykańskiej antropologii jest istotny i bez rze- telnej oceny jego dorobku nie sposób odnieść się do podejmowanych przez niego

Basic concepts of ultraproduct and some applications in Analysis, mainly in Banach spaces theory, will be discussed.. It appears that the concept of ultraproduct, originated as

Dziś jednak skupimy się na pierwszym użyciu czyli planach, zamiarach na przyszłość ( BE GOING TO- ZAMIERZAM).. To stosunkowo łatwa konstrukcja do nauczenia, głównie dlatego,