UK military bridging enjoyed several finest hours during WWII and it would be impossible to describe every single operation. Instead, I am going to look at a significant operation in the three theatres of North West Europe, Italy and the Far East.
The Far East
Operations in the Far East were very different to those in Europe and although the area of operations was enormous British and Commonwealth forces were mainly engaged in Burma.
The initial retreat from Burma saw more bridge demolition that building but the Indian Engineers managed through sheer perseverance and hard work support the retreat.
As plans for the 1943 advance were made routes were chosen and bridging considered, the Manipur River was a significant obstacle, over 350 feet wide at the optimal crossing point. After the Relief of Imphal the Manipur was crossed using light ferries, only capable of carrying jeeps and trailers. These were soon replaced with a larger 16 tonne raft was used but with the rising river caused by monsoon rains operating rafts became impossible.
Locally made PN Boats were bought up and these provided some relief, operating as a pontoon in conjunction with the original rafts. This did not last long as the river rose even more, sweeping all away.
Another crossing used a lightweight suspension bridge, again, only suitable for very light vehicles and foot traffic.
It was time for a Bailey Bridge.
In January 1944 a Class 18 Bailey Bridge was completed, vastly improving the volume of traffic over the pontoons, ferries and lightweight suspension bridge. Later in the year the Manipur was crossed again, this type using a combination of ferries, rafts including a Class 40 Mark V and Class 24 Bailey raft. These were operated as ‘flying ferries’ with Elephants operating as the tractive prime movers. Conditions continued to be extremely challenging with the river flowing at one stage of 12 knots.
The next major obstacles were the Chindwin and Irrawaddy Rivers.
Bailey Bridges were coming into theatre in much greater quantities and the next phase of the advance were in the advanced stages of planning.
Lead elements of the 19th Indian Division crossed the Chindwin using ferries in November 1944 and by the end of the month the entire division had established a strong bridgehead, able to provide protection for the 11th East African Division and the rest of the Fourteenth Army to cross.
The Chindwin is a wide River and a ferry would not be sufficiently capable to support the planned forces crossing in good order so a bridge was planned. This was to be a Class 30 Bailey pontoon with a backup of a Class 12 Bailey pontoon should the heavier bridge not make it forward.
The bridge dump was selected and some 26 miles away from the crossing site, transporting all the bridging equipment from Dimapur, through the Kabaw Valley and Myittha Gorge was no easy task, the roads in the area generally being extremely poor. This approach itself needed 22 timber and 9 Bailey bridges to be constructed.
By the beginning of December all the bridging stores were in place, four sets of 130ft double-double Bailey, four sets of Class 40 Bailey rafts and many pontoons, cordage, Somerfield and coir matting and other construction materials.
On the 6th, work commenced; 67, 76 and 361 Field Companies Indian Engineers, 332 Field Park Company Indian Engineers, a company of the Pathan Engineers Battalion, 852 and 854 Bridge Companies Indian Engineers, under the command of Colonel Seymour-Williams.
Construction of some elements of the bridge took place upstream where there was less danger of Japanese artillery and working conditions for vehicles were better. The construction site was protected by barrage balloons bought up from Calcutta. Grub Bridge, as it was called, after Colonel Seymour-Williams son, was open for traffic 4 days later and the first vehicle crossed on the afternoon of the 10th December 1944.
Grub Bridge was impressive, over 1,150 feet long it was the longest span bailey Pontoon constructed in any wartime theatre and only surpassed by those built over the Rhine after the end of the war and much later by Indian engineers in 1971 in Bangladesh (now), the Wer Madhumati River bridge being just short of 1,500 feet.
In an echo of events in 1982, the BBC announced that a Bailey bridge had been built over the Chindwin and given that a 1,100ft Bailey bridge is not that difficult to spot if one knows the river it is spanning, it was attacked by Japanese fighter and lightly damaged, requiring the bridge to be closed for twenty minutes.
The Grub Bridge was used continuously for 10 weeks after which it was replaced with a more substantial bridge, partly dismantled and floated down river for use in the crossing of the Irrawaddy.
Viscount Slim attributed the speed of the Japanese withdrawal largely to the swiftness of the crossings of the Chindwin and the surprise bought about by this speed. In addition to a number of deceptions and careful siting of the bridge construction site the Indian Engineers quickly put in place a ‘superhighway’ along which significant forces could be moved, reducing the Chindwin to merely a slight restriction in road speed for the advancing forces. It should also be noted however, that the Japanese had intended the area between the Chindwin and Irrawaddy to be semi sacrificial.
Slim seized the opportunity and rapidly changed his plans, deciding on OP EXTENDED-CAPITAL, which was a massive deception. Instead of attacking across the Irrawaddy at the strongest Japanese point he would move part of the 14th Army southwards through the difficult Myittha valley, crossing the Irrawaddy at Pakokku and thus on to the real target of Mektila, a short 80 miles away.
In true Clauswitz style, the simple things were indeed difficult.
All that was needed was to move more or less and entire Corps unobserved, 300 miles through the Kabaw and Myittha valleys, establish a bridgehead on the far bank of the Irrawaddy and then launch the main body across the river to Mektila before the Japanese realised what was going on and that Mandalay was not the main target!
In these days of inter service rivalry it is worth taking a moment to reflect on the truly joint nature of this operation. Without the transportation and air cover provided by the allied air forces none of this would have been possible and equally, although sometimes less noticeable, the Royal Navy had with a great deal of foresight instigated a river tug and pontoon construction effort that would be vital in subsequent operations.
The Indian Engineers would play an equally vital role in the construction of river transportation and there is an interesting quotation from Slims epic take, Defeat to Victory;
One hot day at the beginning of the advance I took Bill Hasted, my quietly spoken Chief Engineer, a little upstream of the Kalewa and said ‘Billy, there’s the river and there are trees. In two months I want 500 tonnes of supplies a day down that river’. He looked thoughtfully at the river and trees, and then at me. ‘The difficult we will do at once, the impossible will take a little longer,’ he quoted from a saying in frequent use in the 14th Army, and added with a grin ’For miracles, we require a month’s notice!’ ‘You’re lucky’, I answered, ‘you’ve got two!’
By the end of the campaign over 540 boats were in use and with the assistance of Commander Holt of the Royal Navy, some of them were even armed. Slim went on to joke that he was the only General ever to have designed, built, commissioned, launched and commanded warships for the Royal Navy. The boats were called Una and Pamela after the daughters of Slim and Mountbatten.
Crossings were of course made higher up the river but these were parts of Slims deception.
Even further South the crossing would not take place at the obvious points and the site chosen was Nyaungu, 20 miles downstream of Pakokku. It is beyond the scope of this post to describe what happened after the crossing but it was a masterful stroke of genius, surprising the Japanese and drawing them into their predictable huge counter offence that would be a simple battle of destruction, they lost.
But what about the bridge?
Well, strictly speaking there wasn’t one.
The initial crossing on the 14th February 1945 to establish a bridgehead was a classic assault crossing and given that in some places the crossing was in excess of 3,500 yards the journey was a long one. Three crossing points were selected and the equipment needed 250 lorries to bring to the assembly point.
First over were elements of the South Lancashire Regiment, silently paddling in assault boats, whilst especially noisy diversionary crossings took place elsewhere. Follow on waves were to use assault boats with outboards but many of these simply failed to start so there was a period of chaos but despite fierce fighting and the need for close air support the bridgehead was established.
Using a collection of rafts including three Class 40 Bailey Rafts the majority of the Indian 7th Division was across by the 15th.
Once the 7th Division was across the next phase necessitated and increase in rafting capacity and over 30 rafts of various types were used to get the 17th Indian Division, 225 Armoured Brigade and Corps troops across by the 22nd of February.
At its peak, the crossing rate was over 100 vehicles an hour.
During the rest of the campaign, bridges and rafts continued to be a vital enabler.
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