Mulberry Harbour Conundrum, any Experts?

Truxx

LE
As it happened old bean,, dug out my scan of the history the other day to help the D-Day 75 planners...

The document is called THE STORY OF THE MULBERRIES, written in 1947 for the War Office by Rear Admiral Hickling (NOIC of Mulberry B) and Brigadier Mackillop (DQMG(Movements) 21 Army Group). It is a combination of engineering and operational history.

The photo from the OP looks to be an 80 feet span of floating roadway. WHALE referred, as others have said, to the overall equipment package to provide quickly erected piers to "provide continuous alongside discharge on flat beaches with a tidal range of up to 30 feet... able to withstand rough weather." It was one of the four main component packages, the others being the blockships, the BOMBARDON floating breakwater, and the PHOENIX caisson harbour-walls. The blockships and BOMBARDONS were naval responsibilities, PHOENIX and WHALE Army responsibilities.

WHALE comprised two principal parts:

a) the SPUD pontoon pier-head; and
b) the flexible floating roadway to link the pier-heads to each other, and, more importantly, connect them to the shore. Came in two classes - Class 40 for tanks, Class 25 for 10 ton lorries plus trailers.

The authors comment that the floating roadway was the most difficult design problem of the whole of the Mulberry project, and luckily one of the first to be tackled. The 80 foot spans as shown in the picture do not seem to have had a specific codename, but the pontoons on which they floated were BEETLES, so called as they were turtle-backed to dampen the wave motions. The BEETLES were also designed so that rubber bags could be inserted easily in them and inflated by a work boat as a temporary fix should they suffer strafing or bomb damage, to reduce the number of occasions a roadway would have to be shut down to allow a pontoon to be replaced. The BEETLES could also be fitted with legs to stop them coming into contact with seabed rocks at low tide. Beehive charges were used by divers to create anchor points for the BEETLES in rock.

There was also a variant span, which was telescopic and could vary between 71 and 80 feet - these were used every four or five standard spans, to cope with the extremes of spring tides - the problem otherwise would have been that you could not build the roadway at a neap tide, and not then suffer embarrassment when the springs rolled in. They were also used to connect the pierheads to each other - as the authors comment, it would otherwise have been "very tedious" to position the pierheads precisely 80 feet apart...

Worth mentioning, if not known, that each roadway span could twist safely up to 18 degrees end to end.

Overall WHALE production was 23 SPUD pontoon pierheads, plus 7 miles of floating roadway spans and BEETLES - 50,000 tons of steelwork made at 240 different factories in the UK, with assembly in the Clyde, at Southampton, and at Richborough. There was a back-up alternate design for the BEETLES in reinforced concrete, since steel-plate was a bottleneck, but these could only be used at the seaward end of the roadways as they did not handle grounding well. In any case, too many concrete BEETLES would in turn have risked a bottleneck on the construction of PHOENIX.
Good man! I knew you would be out there somewhere to put the record straight!
 
Have realised that I have completely failed to answer main thrust of the OP's original question...

There is no mention of "plastic armour" in the Mulberry history. However, the reference you make to "protecting machinery" must refer to the spud pontoon pierheads, since each had a diesel power-plant and electric motors to power the spudded steel legs which gave the pontoon its name. Each of the main pier-head pontoons was 200 feet long, 60 feet wide, and weighed in at 1000 tons. There were also auxiliary dumb pontoons, 90 feet long, used to extend the frontage of the quay where possible, plus buffer pontoons with a sloping face to act as a false beach/ramp for the bow doors of LST-type vessels, and a high level ramp and drawbridge that could be fitted to some SPUDS to allow simultaneous discharge from the upper decks of LSTs.
 
Since I have dug out the papers, some random stats:

Equipment losses:
Tugs - planning assumptions allowed for 10% losses, but only one British and one US tug were thankfully lost.
Mulberry components - planning allowed for 20% in transit. Only two PHOENIX caissons were lost - one to a mine, the other to a torpedo, but nearly 40% of the floating roadway components were lost en route.

Positioning the blockships and caissons was the task of a specialist 40 man RN/Army team, led by a Lt Cdr rejoicing in the title of The Planter. Managed to get most sunk into place within inches of desired position, with each PHOENIX having a sink time of 10 to 20 minutes.

Probably known by some, but the deadweight tonnage handled by Mulberry B up to 31 August 44:
Ammunition - 178,226t
POL - 76,930t
Supplies - 103,852t
RE stores - 153,077t
Coal - 3,095t
Misc - 64,256t

Total of 579, 436. And all that excludes MT!

On a daily basis, the Mulberry B DUKWs alone were shifting an average of 4,800 tons from ship to shore. They were used particularly for ammunition movements. No1 Transhipment Area at Mulberry B had ten unloading bays with cranes for the DUKW cargos, and roller runways to ease loading of lorries. Needed a control tower to oversee / manage the whole site. Had to be supplemented by a second transhipment area in due course.

Record time for unloading a fully laden LST was 18 minutes, using bow doors and upper deck ramp onto the WHALE equipment.
 

HE117

LE
Agreed. 10 years after designing and building the Lancaster bomber the same team gave the world the Vulcan. 10 years. Others, equally talented, having perfected the jet engine and the atom bomb in the meantime.

For some inexplicable reason we have forgotten that we are (or were) seriously seriously good at shit.
In many ways, this was the result of a couple of generations of an education system that was selective but was based on a remarkable degree of equality of access. If you could do something, the system was pretty good at picking this up and supporting it, particularly if it was needed by industry.

Our engineering apprentice schemes and pure science subjects were accessible to those who could do them and there were huge opportunities for gaining knowledge and practical experience in manufacture. My father left state schooling in 1925 aged 15, but ended up twenty years later with a science based PhD, all done part time whilst in full employment and looking after his mother and sisters! I doubt very much if this could have been done today..!

We waste far too much resource on funding mediocre and overblown vanity projects these days, and have lost the plot over the arts v science debate IMHO!
 
Visit Arromanches-les-Bains in Normandy, plenty to see and hear about it all, just avoid the cheap jap tat being sold.
 

Truxx

LE
Have realised that I have completely failed to answer main thrust of the OP's original question...

There is no mention of "plastic armour" in the Mulberry history. However, the reference you make to "protecting machinery" must refer to the spud pontoon pierheads, since each had a diesel power-plant and electric motors to power the spudded steel legs which gave the pontoon its name. Each of the main pier-head pontoons was 200 feet long, 60 feet wide, and weighed in at 1000 tons. There were also auxiliary dumb pontoons, 90 feet long, used to extend the frontage of the quay where possible, plus buffer pontoons with a sloping face to act as a false beach/ramp for the bow doors of LST-type vessels, and a high level ramp and drawbridge that could be fitted to some SPUDS to allow simultaneous discharge from the upper decks of LSTs.
I didn't like to say.....
 

Truxx

LE
Since I have dug out the papers, some random stats:

Equipment losses:
Tugs - planning assumptions allowed for 10% losses, but only one British and one US tug were thankfully lost.
Mulberry components - planning allowed for 20% in transit. Only two PHOENIX caissons were lost - one to a mine, the other to a torpedo, but nearly 40% of the floating roadway components were lost en route.

Positioning the blockships and caissons was the task of a specialist 40 man RN/Army team, led by a Lt Cdr rejoicing in the title of The Planter. Managed to get most sunk into place within inches of desired position, with each PHOENIX having a sink time of 10 to 20 minutes.

Probably known by some, but the deadweight tonnage handled by Mulberry B up to 31 August 44:
Ammunition - 178,226t
POL - 76,930t
Supplies - 103,852t
RE stores - 153,077t
Coal - 3,095t
Misc - 64,256t

Total of 579, 436. And all that excludes MT!

On a daily basis, the Mulberry B DUKWs alone were shifting an average of 4,800 tons from ship to shore. They were used particularly for ammunition movements. No1 Transhipment Area at Mulberry B had ten unloading bays with cranes for the DUKW cargos, and roller runways to ease loading of lorries. Needed a control tower to oversee / manage the whole site. Had to be supplemented by a second transhipment area in due course.

Record time for unloading a fully laden LST was 18 minutes, using bow doors and upper deck ramp onto the WHALE equipment.
Notwithstanding the outstanding engineering and logistic undertaking that was Mulberry I have it in my head somewhere, again from way back, that more tonnage came across the beach than was actually handled by Mulberry. Like most things though it could also be a figment of my aged and beer fuddled imagination.
 
I do know a chap in MOD who pulled the entire mulberry file from the Public Records Office (we needed it for part of the 60th Anniversary of D Day)
!

And actually a very informative read. think I may have my copy still around somewhere.
 

Truxx

LE
Visit Arromanches-les-Bains in Normandy, plenty to see and hear about it all, just avoid the cheap jap tat being sold.
Other thoughts that sometimes make it to the surface based, presumably, on some traumatic events once upon a time, have an Arromanche flavour. One memory involves a heady cocktail of Michael Grade (BBC) bucket loads of vetrans determined to drink the place dry (and making a bloody good job of it), losing my driver to the clutches of a lady BBC producer, and a partially blind Royal Marine with conjunctivitis at the helm of a Winnebago.

But again, it could have been a dream.
 

Truxx

LE
In many ways, this was the result of a couple of generations of an education system that was selective but was based on a remarkable degree of equality of access. If you could do something, the system was pretty good at picking this up and supporting it, particularly if it was needed by industry.

Our engineering apprentice schemes and pure science subjects were accessible to those who could do them and there were huge opportunities for gaining knowledge and practical experience in manufacture. My father left state schooling in 1925 aged 15, but ended up twenty years later with a science based PhD, all done part time whilst in full employment and looking after his mother and sisters! I doubt very much if this could have been done today..!

We waste far too much resource on funding mediocre and overblown vanity projects these days, and have lost the plot over the arts v science debate IMHO!
I think you make some excellent points. I particularly agree with the comment on education - selective and competitive yet accessible.

The other thing that struck me about this particular subject was the extent to which the expertise was uniformed. I know that there was a war on but entities such as RE Tn were formidable in their own right well before hostilites got underway.

Compare and contrast with the current military fixation with the "generalist" and the relegation of real technical expertise to the second division, if at all.

I suspect that there is a threadsworth on this subject alone.
 
Other thoughts that sometimes make it to the surface based, presumably, on some traumatic events once upon a time, have an Arromanche flavour. One memory involves a heady cocktail of Michael Grade (BBC) bucket loads of vetrans determined to drink the place dry (and making a bloody good job of it), losing my driver to the clutches of a lady BBC producer, and a partially blind Royal Marine with conjunctivitis at the helm of a Winnebago.

But again, it could have been a dream.
I was going to say, I remember - just about - you and I sat on the Arromanches seawall in the early hours of 7th June 2004, quaffing wine from a bottle with a seriously grateful BBC reporter, watching the Froggie fireworks launched from the remains of Mulberry B.

I do still have PTSD though from said RM officer's failed attempts to move the vehicle out of the way of 101 Log Bde. As, probably, does the poor RLC Lance Jack who was trying to give him steering instructions, whilst giving you a despairing look that asked, oh so clearly, "Is he seriously a commissioned officer, sir?"

Though for me the highlight was whispering in the ear of a 17 P&M Staff Sgt that the old boy, heading towards him on the beach for a word with him and his lads, was a Field Marshal.

"But we don't have Field Marshals any more, sir!"
"That's the point, Staff. He is Field Marshal Bramall. Landed here 60 years ago. Have a nice chat."
 
Notwithstanding the outstanding engineering and logistic undertaking that was Mulberry I have it in my head somewhere, again from way back, that more tonnage came across the beach than was actually handled by Mulberry. Like most things though it could also be a figment of my aged and beer fuddled imagination.
Absolutely right. Even leaving aside the weight of vehicles, the tonnage handled by Mulberry B, as a percentage of gross deadweight load through the British sector, was 48.4% for the period June to 31 August. Lowest weekly percentages were weeks ending 12 June and 19 June, understandably as the Mulberry was still being built / working up, at 12% of total. Peak Mulberry share was first week of August, when it handled 68.9% of sector load.

Also, of course, plenty came directly across the beach inside the Mulberry, typically 20% of the port's daily discharge rate; 70% if one includes the DUKWs swimming ashore from the ships. Only 10% - but the most awkward 10%, plus a lot of vehicles - came along the floating roadways.
 
Have realised that I have completely failed to answer main thrust of the OP's original question...

There is no mention of "plastic armour" in the Mulberry history. However, the reference you make to "protecting machinery" must refer to the spud pontoon pierheads, since each had a diesel power-plant and electric motors to power the spudded steel legs which gave the pontoon its name. Each of the main pier-head pontoons was 200 feet long, 60 feet wide, and weighed in at 1000 tons. There were also auxiliary dumb pontoons, 90 feet long, used to extend the frontage of the quay where possible, plus buffer pontoons with a sloping face to act as a false beach/ramp for the bow doors of LST-type vessels, and a high level ramp and drawbridge that could be fitted to some SPUDS to allow simultaneous discharge from the upper decks of LSTs.
Actually without noticing you did. You mentioned how many Spuds were built, that number tallies a little too closely to the numbers protected. Which confirmed the possible ID provided by yourself and others.

Also, thanks, I knew I'd find a Mulberry expert somewhere.
 
I wasn't thinking in terms of it igniting, more of the molten stickiness and fumes. It would start to soften at around 90 centigrade and act as a viscous fluid at around 120 centigrade. Being in contact with the stuff would be horrendous as the only way to remove it would be by soaking with diesel.
Sorry I had wanted to answer this, but got side tracked.

The risk is, frankly a bit negligible. Plastic was normally cooked up at about 230 degrees C. In mostl cases the plastic was applied to the outside of the location to receive it. If you have a fire that is able to generate those sorts of temperatures outside, then I would argue that you have vastly bigger problems than the walls getting a bit runny.

Equally, the Bitumen only accounted for ~8% the total weight of the Plastic, and that was in the first version only. The amount dropped in later mks. By comparison the same mark of Admiralty Specification* PA Mk.I had some 37% of its composition as limestone powder.

*Yes, this distinction is needed to separate it from Bence-Jones PA, US PA, Indian patten PA. Both the latter were so widely variable its amazing. Indeed the US stuff was described as 'Bootleg' PA by one officer, which gives you an idea of the sate of US production was like in the early years, as there was almost no regulation or standards for it, and several companies were just chucking stuff out that had almost no official sanction to make a fast buck.
 

ugly

LE
Moderator
I seem to recall a complete set of mulberry models in RSME Chattenden in the 1980's. I wonder if they ended up in the RE museum? They were in the halls of the classroom area, Burgoyne study centre anyone? They were in glass cases along with loads of models and other interesting items.
 
Agreed. 10 years after designing and building the Lancaster bomber the same team gave the world the Vulcan. 10 years. Others, equally talented, having perfected the jet engine and the atom bomb in the meantime.

For some inexplicable reason we have forgotten that we are (or were) seriously seriously good at shit.
as per the guardian comment.

many leftards want us to fail, because we once ruled an empire on which the sun never set.
 

Truxx

LE
I seem to recall a complete set of mulberry models in RSME Chattenden in the 1980's. I wonder if they ended up in the RE museum? They were in the halls of the classroom area, Burgoyne study centre anyone? They were in glass cases along with loads of models and other interesting items.
Another complete set was at Marchwood Military Port.
 

Mikal

ADC
Thanks, that has pretty much cemented what Truxx suggested.



Trouble is as I do research, I've gone off books, because why read someone else when I can get the documents from the original source and be sure I've got everything. Yes, I've turned into a source snob.
Plus I'm contemplating writing it up myself possibly for a book.
The trouble with other peoples books is that they compound inaccurracies - the bibliographies are a good help. I had some great discussions with some authors about he source of heir information withmany admitting they had quoted other books without checking for accurracy. Some of them had never checked orignal documents.
 
The trouble with other peoples books is that they compound inaccurracies - the bibliographies are a good help. I had some great discussions with some authors about he source of heir information withmany admitting they had quoted other books without checking for accurracy. Some of them had never checked orignal documents.
I agree, hence why I never use other books for sources, unless I have no option. Of course stuff like eye witness accounts (which are already somewhat unreliable) are often only available in older books.

I do wonder if some of the more prolific and well off authors fall into the category you describe. Jsut churn out facsimiles of other works, it does seem to be the only way to make an income from history writing (at least from my lowly position).
 

SpiderFox

Swinger
Year old thread revival I know, but there's this picture in the D-Day museum in Portsmouth which shows the various components in "picture" form. Not the greatest photo but it was through the glass cabinet:
Mulberry.jpg
 

Latest Threads

Top