The Combat Engineers of D-Day - WW2 Special Documentary

The engineer, the sapper, the pioneer, - maybe no other military outfit has seen its craft be refined so quickly by the rapid progress of the technology over the last 150 years as engineers. By now all major nations have expanded their engineering outfits from small brigades to corps of hundreds of thousands of men. But how were they used last month during the massive Allied amphibious invasion of Normandy? And how are they used in general? Let's find out. I'm Indy Neidell, and this is a WW2 spe

cial about engineers and the engineers of D-Day. Why, you may ask? Well, we wrote this back then, but there wasn't room in our 24 hour D Day series for it, so you get it now. The engineer's task is to support both the army's combat and its supply elements. Efficiency and firepower are to be increased by the means of construction or destruction, by either facilitating or impeding movement. Close to the front they dig trenches and tunnels, string wire or bridge shell holes, while facing the same d

angers as regular infantry. Further back, engineers are constantly building and rebuilding roads and railways, setting up camouflage screens to conceal guns and positions, and establishing lines of communication between the front and the rear. To support combat operations, they set up ranging equipment for artillery units or handle supply dumps. Chemical experts have even unleashed poisonous gas in wartime, or neutralized its effects. From mine warfare, to forestry and topography, the engineerin

g corps relies on all kinds of knowledge and tricks to outclass the enemy in the field. And that is most definitely needed on D-Day. Using engineers in amphibious landings wasn't really on anyone's mind before the war. American engagements on the islands of the Pacific and British endeavors in the Mediterranean, however, showed how much their support and technical expertise is needed. And once the clock hits H-Hour on D Day, wave after wave of landing craft and amphibious tanks are to land on No

rmandy's beaches and swarm as quickly as possible over the German defenses at the draws and beach exits. Since German High Command considers landings at low tide highly unlikely, their engineers have placed rows of obstacles at the tidal line. Around 250 meters from the shingle are the "Belgian gates". These are quite literally closed off gates that serve as mobile barriers. Often lined up with waterproof mines, the Germans expect to catch enemy landing craft as they race towards the shore at hi

gh tide. Behind the gates stand irregular rows of sharp steel stakes, as well as V-shaped rails that can shear into the bottom of the boats. In between them are mined logs. Basically one upright wooden pole, supported on two trailing legs, onto which the landing craft is to slide and then hit the mine at its top. Then, closest to the high water mark, are the Czech hedgehogs. These have been welded and bolted together at their centers to become excellent roadblocks for vehicles and tanks. Through

out the spring, the Allies photograph Normandy from high altitudes and the photos clearly show that the Germans are increasing their efforts to beef up their defenses. Obstacles multiply by the month, as do rows of barbed wire and minefields. On April 23rd, a single bomb dropped creates over a dozen secondary explosions, demonstrating the thickness of the enemy minefields. So, to deal with all these obstacles as quickly and efficiently as possible, the Allies set up specialized training regimens

and develop adequate stratagems and equipment. Because if they want to undo Hitler's stranglehold on the European continent, then they have to examine the roles for amphibian engineers. Engineers are generally divided into two outfits: Most are for general service. This includes everything from constructing large-scale rear area bomber bases, to erecting supply and ammo dumps in the rear, all the way to digging field emplacements at the front. But there are also more specialized units designate

d for direct combat support. These are sent to amphibious training schools. The British established an Underwater Obstacle Training Center, in preparation for amphibious landings in the Mediterranean. The US Navy mirrors their efforts at the Navy's Amphibious Training Base at Fort Pierce. Of course by 1944, the Allies can draw deeply from their mutually acquired experience. Still, those engineers in the European theater for D-Day need considerable training, particularly about the conditions at t

he French coastline. They calculate that the Germans do not have the numbers to use more than one platoon per 2,000-2,500 meters to man the beach fortifications. However, the number of enemies is not of importance to the engineers. It is their primary job to eliminate the beach fortifications, the concrete bunkers, pillboxes, sea walls and dugouts. Sure, they train with flame-throwers to clear trenches and shelters, or bangalore torpedoes to blast their way through barbed wire, but killing enemy

soldiers is generally not their prime objective. To prepare the engineers on how to deal with the array of German beach defenses, a specialized Assault Training Center is constructed on the northwest coast of Devon in March 1944. This allows only two months of actual invasion training and a couple full-scale exercises, but that has to do. Here the men are drilled in locating and unearthing mines, disarming camouflaged booby-traps, as well as working in concert with the demands of drivers and me

chanics. Standardization of equipment is a given to save time in equipping the men. British and American engineers have to find common methods for solving tactical problems in the field, as well as settle on a specific set of terminology and nomenclature to eliminate misunderstandings. There are also a bunch of new inventions ready for D-Day, like the battery-operated magnetic mine detector, which makes detecting and unearthing mines in the field much quicker. Or specially perforated steel beams

, which are much lighter than before but still sturdy enough to support tanks over poor or unstable soil. There are several experimental devices along the way. Like a remote-controlled drone boat - the "Apex". Or the "Reddy Fox", which is an explosive-laden pipe that can be towed into the landing areas. The big interest in explosives is because of Operation Neptune`s tight schedule. For example, the "Hagensen packs" are developed to flatten the big Belgian gate with as little danger to the surro

unding men as possible. These are waterproof canvas bags shaped like sausages, and each is filled with a kilo of C-2 plastic explosives. They have a hook at one end and a cord at the other, so that several bags can be connected via primer cord and put around obstacles like the Belgian gate. Around 16 Hagensen packs are needed to flatten such a gate if they all explode at the same time. Literally at the eleventh hour, tens of thousands of such explosive sausages are produced and delivered to the

combat engineers. The engineers themselves come from both the Army and Navy's special brigades and demolition units, and are to be landed in boat teams of up to 40 men at the beach. The sailors focus on destroying the seaward obstacles, while the army sappers start with those inland. Each boat team carries up to 500 kilos of explosives, as well as a wide assortment of accessories. These "Assault Gapping Teams" are the tip of the spear and are intended to pave the way. Taking OMAHA Beach as an ex

ample- here the engineers are expected to blast two gaps in each sub-sector. These gaps have to be up to 50 meters wide to allow for vehicles to easily and quickly come through. Once the spearhead of combat engineers has cleared the paths, the Engineer Special Brigades will then arrive and deploy all the bigger stuff needed to clear mines or reinforce roads. Then the heavy stuff will follow, stuff like Tank Dozers. Afterwards, once the fighting is done, the ordnance battalions will take over the

beach and operate all the dumps and supply lines. These ordnance battalions are technically also part of the engineering corps, although lean heavily into supply outfits. Overall, the organization of the corps is pretty diverse, because their job demands many different experts and specialists. In another specialized training center in Wales, engineers are schooled in construction and repair. In yet another training center set on the Isle of Wight, engineers are trained in constructing marine pi

pelines, and in a seven-week course at the Transportation Training Center, they learn the art of railroad work and bridging. Dealing with terrain problems is usually the main focus in all of these courses. See, from the get-go, the seaborne invasion will be confronted with slippery sand at the beaches, obstacles hidden by a rising tide, and rocky shingle right behind the high water mark. The bluffs and cliffs behind the beaches are equally tough terrain to move through, especially with the Germa

ns fortifying the whole area with mines and wire. And once on the march inland, the Allied armies will have to find their way through flooded pastures, narrow dirt roads and causeways, and a countryside full of wreckage, bomb-craters, and ruins. Without the expertise of their supporting engineers, the Allied columns will find themselves bogged down quite literally, and it would certainly pay off to have specialists that know how to rapidly construct bridges or how to mount pneumatic floats over

flooded craters. Although the basic unit framework of the Great War still applies to its sequel, all nations have developed new types of equipment and organizational structures for their engineers, as everything has drastically increased in scale. For example, the 5th Engineer Special Brigade is in itself divided into an engineer combat battalion, a naval beach company, a quartermaster service company, a DUKW company, a medical collection company, a quartermaster railhead company, a platoon of a

quartermaster gasoline supply company, a platoon of an ordnance ammunition company, a platoon of an ordnance medium automotive maintenance company, military police, chemical decontamination and joint assault signal platoons, two auxiliary surgical teams, three quartermaster service companies, three quartermaster truck companies, an ordnance medium automotive maintenance company, and, to round it all off, a utility detachment. From a sheer organizational standpoint, this is far beyond anything t

he Germans can muster at this point. But despite this complexity, engineer units are rather organic in nature, and can be quickly attached to different battalions and regiments. Maybe the largest impact the engineering corps has is on the motorization and mechanization of armies. Engineers have had to develop a whole new set of skills to facilitate the unimpeded movement of wheeled vehicles and tracked tanks. Harnessing the power of the internal combustion engine has made this war much more mobi

le than its predecessor, and has allowed for new tactics in the field, and given the engineers a whole new set of toys to play with. Allied industrial muscle in 1944 is something that German pioneers can only dream of. American and British engineers are to be supported by heavy machinery - I'm talking bulldozers, scrapers, trucks, cranes, and many other different types of earth moving, road paving, and bridge constructing machinery, but with the immensely high consumption of gasoline and oil of

motorized and mechanized armies in combat, the engineers must closely work together with the Quartermaster Corps. They also often take over laying and improving pipelines along the roads, to connect the rear areas of the advancing armies to the major supply depots at the ports. Speaking of ports, last year's landings at Naples confirmed the fears that enemy sappers would rather destroy the harbors than letting them fall into Allied hands. German engineers and specialists of the construction orga

nization "Todt" sank blockships into harbor approaches, as well as littering the harbor's channels and berthing areas with mines and all kinds of other unpleasant obstacles. So, the Allies prepare plans for major reconstruction and rehabilitation programs to dredge them clear before even beginning supply operations. And that means lots and lots of explosives, replacement parts, and specialized equipment must be made available to the engineers to remove these blockages. And not just that, but sop

histicated stuff like shallow-draft repair ships and floating machine shops are needed to bring ports back into operation. Even the most optimistic people think that the major French ports will not be fully available until at least 90 days after D-Day. And even if they get lucky and overwhelm the Germans quickly before they can destroy a port, most of the harbor installations will be out of commission anyhow either by being neglected by long inactivity, or by Allied bombing runs or acts of sabot

age by the French resistance. The widespread destruction has also shown that simply relying on the local infrastructure would be a grave mistake. Experts estimate that the destruction of the traffic grid could reach up to 75%. In fact, they reckon that most of the road and railway bridges up to 50 kilometers from the major centers closest to the invasion zone will be damaged or entirely unusable. Engineers will certainly have their work cut out for them, as SHAEF expects large parts of Normandy

to be wrecked. Either by the preliminary Allied bombing run, the damage caused by the French resistance's sabotage acts, or demolished during the retreat of the Germans - northern France's infrastructure will likely be in a dismal state, but its ports and waterways must be rehabilitated quickly to support the invasion; destroyed bridges must be rebuilt and damaged railway lines and roads repaired; water supplies restored and guaranteed. For this the engineering corps needs to produce accurate ma

ps. It is vital for their job to have the most accurate assessment of enemy's defenses, so they know what equipment to bring into which sector. Great interest is taken in the multi-lens cameras and multiplex interpretation systems integrated into reconnaissance planes. On these maps, the engineering officers involved in D-Day begin locating the best possible terrain near the ports to establish suitable supply arteries. Knowing the exact locations of roads, railways, bridges, and flooded areas is

crucial for the support units to divide their forces. On these "topo maps", the mapmakers draw topographic contours and divide them into smaller military grid squares. Then the engineering officers set the optimum approach to lay communication and logistic lines to support the armies as they march inland. This includes such things as air strips, storage dumps, gasoline and water pipelines, as well as anti-aircraft defenses in regular intervals, just in case the Luftwaffe decide to show up. Usin

g aerial photography, engineering planners have studied the amount of railroad bridging they will need. Same goes for estimates about track maintenance, railroad grades, the number and length of sidetracks needed, the carrying capacity of various lines, bridge capacities, water and commercial facilities, and available materials. Keeping roads in shape will minimize the time needed to transport and distribute supplies, ammunition and construction materials. Of course, everything has to be calcula

ted beforehand, and not just for D-Day but for the weeks and months after. How much labor and material is needed to repair a mile of road or rail? How many gasoline pipelines are needed to provide for machinery on shore? How much TNT, wire, and detonator caps are needed to blast through a sea wall? Taking just Omaha Beach D Day calculations as an example, the beach-obstacle clearance teams require twenty-eight tons of explosives and seventy-five miles of priming cord. There is of course a multit

ude of miscellaneous engineer items, like minefield gap markers, detectors, and clearing equipment, or let's say, special towing cables for D-8 armored dozers. All this, endless tons and tons of this, has by now been brought ashore in Normandy, and the engineers are still hard at work after these weeks of invasion, transforming their environment. And the environment in Italy, and in the Soviet Union, and in China, and in India, and the Pacific Islands…. And that's just the Allied engineers. But

looking at that whole picture you can see what a colossal endeavor it is- beyond any of the fighting- to make modern war. If you somehow missed our 24 hour coverage of D Day, we even put it on its own dedicated channel for your convenience, so go check that out. Right here. And join the TimeGhost Army at patreon.com or timeghost.tv. Do not forget to subscribe; see you next time.