Anything to do with ancient China always seems to elicit a great deal of discussion and debate so the historical reference points for the emergence of military bridging are varied but most historians see China as the first recorded place that military bridging used pontoon bridges several hundred years BC
These were commonly called a bridge of boats or pontoon bridges.
Greece and Rome
Although not strictly British it is useful to set the scene.
A large pontoon bridge was constructed in 480BC for Xerxes the Great of Persia across the Hellespont, or Dardanelles in modern terminology, that separated Asia from Europe. The first bridge was made of papyrus and flax; unsurprisingly it was destroyed in a storm to which Xerxes entirely sane reaction was to have the engineers beheaded and the water flogged.
A later pontoon bridge was sturdier, the Greek writer Herodotus wrote;
and meanwhile other chief-constructors proceeded to make the bridges; and thus they made them: They put together fifty-oared galleys and triremes, three hundred and sixty to be under the bridge towards the Euxine Sea, and three hundred and fourteen to be under the other, the vessels lying in the direction of the stream of the Hellespont (though crosswise in respect to the Pontus), to support the tension of the ropes. They placed them together thus, and let down very large anchors, those on the one side towards the Pontus because of the winds which blow from within outwards, and on the other side, towards the West and the Egean, because of the South-East and South Winds. They left also an opening for a passage through, so that any who wished might be able to sail into the Pontus with small vessels, and also from the Pontus outwards. Having thus done, they proceeded to stretch tight the ropes, straining them with wooden windlasses, not now appointing the two kinds of rope to be used apart from one another, but assigning to each bridge two ropes of white flax and four of the papyrus ropes. The thickness and beauty of make was the same for both, but the flaxen ropes were heavier in proportion, and of this rope a cubit weighed one talent. When the passage was bridged over, they sawed up logs of wood, and making them equal in length to the breadth of the bridge they laid them above the stretched ropes, and having set them thus in order they again fastened them above. When this was done, they carried on brushwood, and having set the brushwood also in place, they carried on to it earth; and when they had stamped down the earth firmly, they built a barrier along on each side, so that the baggage-animals and horses might not be frightened by looking out over the sea.
The Romans were great military engineers and many of their military constructions stand to this day.
During the First Dacian War in 200AD Roman engineers constructed a large pontoon bridge over the Danube
This was somewhat overshadowed by the famous Trajan Bridge which for more than a thousand years was the longest arch bridge in the world.
One of the earliest instances of military bridging in the UK was King Edward 1’s attempt at crossing the Menai Straits in Wales, although it was hardly an auspicious start. In 1277 in order to quell a Welsh rebellion King Edward I sent a force of 2,000 soldiers to capture Anglesey, thus depriving the opposing forces of much of their food supply and to outflank defending forces at Conwy.
The Warden of the Cinque Ports (Stephen de Pencaster) was given the construction task and used carpenters and shipwrights from his area to create the bridge, comprising a number of interlinked boats, commonly called a ‘bridge of boats’.
Unfortunately these were too heavy to be conveyed by the naval force and a second set had to be constructed at Chester.
Despite the bridge being perfectly adequate, poor communication and coordination meant the English forces crossed at exactly the wrong moment and were caught between a rising tide and the opposing forces with obvious results.
Walter of Guisborough wrote;
When they had reached the foot of the mountain and, after a time, came to a place at some distance from the bridge, the tide came in with a great flow, so that they were unable to get back to the bridge for the debt of water. The Welsh came from the high mountains and attacked them, and in fear and trepidation, for the great number of the enemy, our men preferred to face the sea than the enemy. They went into the sea but, heavily laden with arms, they were instantly drowned.
Edward also made use of military bridge builders in Scotland, this time to greater effect.
Commissioning Kings Engineer (Magister Richard) to create a set of portable bridges at Kings Lynn in Norfolk, he went on to use them to cross the River Forth, neatly bypassing the heavily defended Stirling Bridge.
The next major milestone in UK military bridging is the establishment of the Board of Ordnance in 1597 and subsequently Ordnance Trains which although were predominantly concerned with artillery had a significant combat engineering element. Ordnance Trains were raised only in times of war and built on a small full time contingent.
In 1704 British and Dutch forces captured Gibraltar and the territory was granted to the UK in perpetuity in the Treaty of Utrecht in 1714. Gibraltar and other overseas territories needed a larger contingent of engineers to develop infrastructure and fortifications and although not necessarily bridging related it is important to understand the source of an expansion of military engineering.
The regular Corps of Engineers was formed under a Royal Warrant on May 26th 1716, although it only consisted of a handful of people without military rank. This split the artillery and engineering functions that had been combined in the original ordnance trains.
In 1757 the members of the Corps were granted military rank, commissioned by the King.
In 1787, another royal warrant was issued, this time conferring the title Royal.
We are further pleased to direct that Our said Corps of Royal Engineers shall rank in Our Army with Our Royal Regiment of Artillery, and whenever there shall be occasion for them to take post with any other corps of Our Army the post of the Corps of Royal Engineers shall be on the right with the Royal Regiment of Artillery, according to the respective dates of the commissions of the officers belonging to the Royal Regiment of Artillery and Corps of Royal Engineers. And for so doing this shall be, as well unto you as unto all other officers and ministers herein concerned, a sufficient warrant.
After using a number of improvised pontoon bridges in India General Sir Arthur Wellesley returned to Europe to start his long series of dust ups with the French.
A significant bridging effort in 1812 was over the River Tagus is Spain, the original Roman bridge was funnily enough called the Trajan Bridge (see above) and was about 190m long, constructed of granite without the use of mortar. The bridge was strategically vital and alternatives such as fords were not available. In 1809, Lord Wellington (as he was now known) ordered the bridge destroyed to impede French freedom of movement and although the explosive demolition was not entirely successful a single arch collapsed some time later, the locals being somewhat less than impressed, especially because although it was a British military commanded operation, the actual forces involved were Portuguese.
As the tides of war changed, in April 1812, Wellington instructed Lieutenant Colonel Sturgeon to effect a repair. Sturgeon was not an officer of the Corps of Engineers but instead the Royal Staff Corps. The design was to create a suspension bridge, spanning the destroyed arch. Construction took place away from the bridge site and transported using wagons. Once on site ropes were strung across the gap and pulled tight, onto these the rolled up bridge was unfurled and secured.
The superb website Napoleon Series quotes from General Leith Hay, commander of the 5th Division
The arch destroyed was of so extensive a span, and the parapet of the bridge so great a height from the bed of the river, that no repair by using timber was practicable; the gap to be passed over being ninety feet wide, and the height of the bridge, one hundred and eighty from the bed of the river… The work was commenced by placing two beams on supporters four feet high and ninety feet asunder. These were secured to the side and end walls of the building by braces and tackles, to prevent their approximating by the straining of the ropes. Eighteen cables were then stretched round them, extending from end to end; eight pieces of timber, six inches square, at equal distances, were placed upon the ropes, with notches, one foot asunder, cut on their surface to secure them; these notches were seared with hot irons to prevent the ropes from chafing. The cables were then lashed to the beams; they were netted together by rope-yarn, and chains of sleepers were bolted and laid on the network, and secured to the two beams originally placed at the extremities of the work. Planks were cut and prepared for being laid across, bored at the ends so as receive a line destined to secure them to the sleepers and to each other… The next point was to prepare the edge of the fractured part of the bridge, and to cut channels in the masonry for the reception of the purchases. When arrived on the spot, four strong ropes were stretched from side to side, as conductors, for passing the cable-bridge across, the beam on the south side having been previously sunk into the masonry; the whole was then stretched by windlass erected on the opposite pier, by which means it was so tightly drawn as to prevent any great sinking, or the vibration which might render it insecure and dangerous, even when heavy weights were passed over
To understand the importance of this and a subsequent destruction of the French pontoon bridge at Almaraz these two simple acts reduced the march distance for Wellington’s forces by 250km and added 650km for the French.
The bridge was illustrated in the Royal Engineers Journal and a model can be seen in the Spanish Army Museum
Once completed, a column of siege artillery was able to cross the Tagus with ease on their way to Salamanca.
As Wellington prevailed in Spain he pushed into France.
In order to blockade Bayonne on his way to Toulouse, the River Adour would need to be crossed. Selecting the crossing site was compounded by the presence of French garrison forces so in order to provide some protection a site downstream was chosen, this however, meant the gap was larger (nearly 275m) and subject to strong tidal fluctuations.
Two Corps of Engineers officers (Lieutenant Colonel Elphinstone and Lieutenant Colonel Burgoyne) and one from the Royal Service Corps (Lieutenant Colonel Sturgeon, again) were tasked with this significant challenge. Lieutenant Colonel Burgoyne would later go on to achieve the rank of Field Marshal and incidentally, have a building (The Burgoyne Study Centre) named after him at the Royal School of Military Engineering in Chatham.
Due to the size of the gap and extreme tidal fluctuation it was obvious that conventional pontoons or a suspension bridge would not be up to the job so they decided on a solution that used local coastal vessels called chasse matrees. These were large boats, some in excess of 15m long. 48 boats were ‘hired’ and the plan called for them to be moored at 10 to 12 metre centres with the bridging surface combining timber planks. Because of the large quantity of timber that would be needed Lieutenant Colonel Sturgeon suggested using a similar technique to that employed by him in the construction of his bridge over the Tagus in Spain, using ropes to provide a surface onto which a reduced number of planks could be placed.
The cables were paid out towards the shore from the two centre boats and secured using weights (18 pounder cannons) and capstans anchored into the ground.
Under a Royal Navy escort the flotilla of boats set sail on the 22nd of February 1812.
Because of the fast flowing river this was easier said than done and the effort to establish the bridge was considerable, a number of boats were lost to weather and tide, only 34 making it to the bridge site. A bridgehead was also established on the far bank and had to fight off a strong attack from the garrison.
The Subaltern by George Robert Gleig, published in 1825, describes the operation in some detail but the most interesting segment is the description of anchors for the pontoon boats.
I need not add, that no economy was exercised in the matter of anchors
Working through the night the bridge was quickly finished and by noon the next day was being trafficked by troops, wagons and artillery.
The historian Napier said of the bridge;
A stupendous undertaking which must always rank amongst the prodigies of war
What came next can be read here
Wellington took a great deal of interest in military bridging and fully realising the strategic advantages it could deliver, much more attention was therefore given to the subject.
Permanent Bridging Trains were introduced and the Royal Engineer Establishment created. In 1812 a Royal Warrant established a permanent training facility at Chatham for the instruction of Corps of Military Artificers (later Corps of Sappers and Miners) and Royal Engineers.
During the Peninsula Wars Wellington also realised that bridging equipment needed to be highly mobile, took the horses from the Artillery Train and gave them to the engineers. Writing in his despatches he wrote;
We have been sadly delayed by the movements of our bridge, without which it is obvious that we can do nothing, the equipment is quite new and has marched only from Abrantes but there has already been much breakage and I understand the carriages are shamefully bad. I shall have sad work for this bridge throughout the campaign and yet we can do nothing without it.
The end of the Napoleonic Wars ushered in nearly 50 years of European peace but British forces were engaged overseas in India for example.
In 1839 during the advance in Afghanistan a very long span pontoon bridge was constructed at Bukkur, now in Pakistan.
Bukkur is a fortified island on the Indus, between Sukkur and Itoree and a natural crossing point. The bridge itself consisted of two spans, one 200m long and the other over 300m, using over 90 boats and 14 days to construct. Although the high speed of the river its rocky banks caused problems the bridge allowed several thousand troops and equipment to cross.
The Asiatic Journal and Monthly Register (May to August 1839) records events around the crossing including this gem;
PS, the bridge of boats has just given way, and several camels have been carried off, no one knows where
A further detailed account can be read here
Later in the century bridging continued to play an important role in Abyssinia, the Crimea, India, West and Southern Africa
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