MULBERRIES
By D. H. LITTLE
MY first contact with "Mulberry" took place
a week before Christmas, 1943. Sir Arthur
gave mc a set of drawings of some floating break
waters with instructions to report on how suit
able they might be if subjected to storm waves
eight feet high. I was warned that the job was
Top Si cri t and that no more men than abso
lutely necessary, were to deal with it. From
that day until "D" Day the only people who
bandied Mulberry in the Drawing Oflicc
were Mr. E. Evans (now resigned), Mr. Minni-
kin (now with the Superintending Civil Engin
eer, Bristol) and myself. Outside the Drawing
Office, Sir Arthur and Dr. Chatley (now re
signed) were the only engineers involved, while
all the papers were filed by Mr. Gervase Rendell
personally. (I have no strong recollection that
the filing system adopted was very original
but all the entries were in manuscript and most
legible.)
At that -very first contact, none of us in the
Drawing Office had any idea what Mulberry
stood for, but the drawings were marked
Phoenixand showed large box-like struc
tures of reinforced concrete in outlinesome
thing like shoe boxes without lids, and divided
up inside with cross walls after the style of egg
boxes. There were four different types- all
about 200 feet long but of varying heights and
widthsthe smallest being 25 feet high and
weighing 1,660 tons, and the largest 60 feet
high and weighing 6,000 tons. They were in
tended to be towed across the sea and then
sunk in pre-arranged lines so as to form a
sheltered harbour in which ships could lie at
anchor and be protected against stormy seas.
Such structures are by no means novel and
permanent commercial breakwaters have been
built all over the world on similar lines, except
that invariably the hollow caissons-as they
are usually termedare filled with sand, as
soon as they are sunk into position, to give them
appropriate weight and strength. We under
stood, however, that the caissons we were now
concerned with were not going to be filled, and
our calculations soon indicated that in waves
eight feet high they might rock badly. This was
rather an alarming conclusion. The job was
obviously an extremely important one, and
although there were no designers' names on
the drawings it seemed reasonable to assume
that important people had been responsible.
Before stating officially, therefore, what we
thought, we tried to find out a little more about
the original designers. We were not successful
in this, and so with a hectic last-minute rush a
report left the Department on Christmas Eve
stating that in our view the structures were not
strong enough as a whole for their purpose.
This was intended to draw blood, which it
certainly did.
Two weeks later 1 accompanied Sir Arthur
and Dr. Chatley to a very high-level meeting
in London at which Admirals and Generals
were in the majority. At this meeting I realised
that Mulberry was the code name for com
plete new harbours with port facilities to be
built oil' the French coast for the invasion,
and that Phcenix was the code name for
those units which were to form the fixed break
water protection to the harbour. As a result
of this meeting we had close consultations with
the Army Engineers, who had designed Phoe
nix," and we agreed that while the waves would
almost certainly cause them to rock, it was
unlikely that the blows would last long enough
to topple them right over. We were firm in
our view, however, that the units might be
pushed bodily along the sea bed, and accord
ingly it was decided(a) that an attempt should
be made to add sand to them when in position,
and that the breakwaters as a whole
should be strengthened by sinking ballasted
block ships in line in front of them. There was
no possibility by then of amending the design
because many units all over the country were
well advanced in the actual making. Later on
when details of construction became available
we suggested some simple but very important
adjustments to the steel reinforcement of the
outer walls, and these were adopted in the last
units to be built.
In the main, the various components such
as breakwaters, pier heads, jetties and roadways
which went to the making of the Mulberry
harbours were the responsibility of the Army,
who arranged with teams of private designers
and contractors for the design and building of
them in this country.
Two harbours were planned and actually
built Mulberry A and Mulberry B. Both were
built from similar components, made mostly
by the British, but Mulberry A was assembled
and constructed on site by the Americans for
the U.S.A. Army, while Mulberry B was put
together by the British for our Army.
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