At the time, the Normandy invasion was the largest military operation ever undertaken. Thousands of soldiers, sailors, airmen, and coastguardsmen took place in Operation: OVERLORD. This segment will outline only those engineer units involved directly with operations on Omahd Beach supporting the 29th Division. Beacue of the magnitude of the invasion, confusion arises as to what unit did what. One of the more confusing aspects of the Normandy invasion is the plethora of engineer units. It is simpler to think of the engineer support in three main phases:
1. Special Engineer Task Force (SETF) - Landed on Omaha Beach with the 1st and 29th Infantry Divisions.
2. Organic Engineer Battalions. These were assigned to support the combat functions of the assaulting divisions. Each division had its own organic engineer battalion assigned in the initial landings. Each division had its own organic engineer battalion assigned for the initial landings and each assault regiment had had a second engineer battalion assigned to the initial landings. This second battalion was usually assigned from higher Corps.
3. Lastly came the enginner units concered with operating on the beaches as a place for troops to land and for supply dumps to be stablished. The last function was the role of the engineer units composed of the U.S. Navy Engineer Special Brigades (ESBs).
For simplicity and brevity, only the roles of the SETF and the Engineer Combat Battalions will be discussed here.
Special Engineer Task Force (SETF)
The SETF assigned to Omaha Beach was comprised of the 112th Engineer Combat Battalion, the 146th Engineer Combat Battalion, and the 299th Engineer Combat Battalion (less Company B whihc landed on Utah Beach). Like other assault units, this was temporarily attached to the 1st Infantry Division; at the time the most experienced Division in the US Army.
Their primary mission was to prepare 16 fifty yard wide gaps through all obstacles with the tidal range on Omaha Beach. Two gaps on Fox Greeen, six gaps on Easy Red, two Gaps on Easy Green, two gaps on Dog Red, two gaps on Dog White and two gaps on Dog Green. Their secondary mission was to remove all obstacles on Omaha beach.
The SETF was divided into various "Gap" teams and "Support" teams and, at the time of the invasion, was nearly 900 men in strength. An Army Gap Assault Team was composed of 1 officer, 25 enlisted men, and 1 medic. Each team was divided into 2 demolition crews and 2 mine crews, although no records describe the actual composition of these crews. A reserve of an extra 1,00 pounds of explosives was carried in each gap team boat, stored in a rubber raft. These extra explosives was pulled out of the LCM after beaching.
The Gap teams were to land at H+3 minutes in LCMs. Initially, the SETF would start to demolish obstacles closest the surf line, and work towards the baech. The 121st Engineers would move to the next belt of obstacles and work into the shore.
The plan called for the gap team to rig all obstacles with explosives tied together with primacord and set off in one major blast. These gaps were supposed to be 50 yards wide and run the 300 yards from the shore out to the farthest line of obstacles. Once blown, one man would place a gap marker on the beach to indicate to the following boats where the obstacels had been cleared. The marker was a white triangle 2 feet wide at the bottom and mounted on a 6 foot pole.
The rest of the team was to open and mark a 50 yard gap from the low to the high water line. When finished with the 50 yard gap, they were to continue to widen the gap until the beach was cleared of all obstacles.
Mine crews would search and for and destroy any mines mounted on obstacles with hand emplaced demolition charges. They were to then cut paths through the barbed wire strung between the obstacles. Once the initial area was cleared, the breach was widened and marked with white engineer's tape.
121st Engineer Combat
Battalion
Each Divison had its own permanently-assigned Engineer Combat Battalion - in the 29th Division, this was the 121st Engineer Combat Battalion. These engineers would move inland with the unit, suppoorting it in combat and providing counter-obstacle, counter-mobility, mine-clearing, bridge-building, demolition, and construction support as needed. Attached engineer units were a different story. They were seperate units permanently attached to the 1st Army and assigned as needed at either Corps or Division lvel. They would land with the assault division, but soon after the front line passed inland, they reverted back to the control of 1st Army and would be assigned to any future task in the Army's area of operations.
The 121st Engineers were assigned the D-1 (Vierville sur mer) exit and the 113th Engineers the D-3 (Saint Laurent sur mer) exit. The horrific chaos combined with the powerful German Emplacements on Dog Beach delayed both of the these units,. The 121st Engineers tool severe casualties in men and equipment following on the heels of the decimated 116th Infantry. The 121st lost most of their explosives during their intitial landing. The Battalion commander was wounded as well. In conjunction with remnants of other engineer units in the area were finally able to open the D-1 exit for vehicular traffic by late afternoon on June 6th; roughly the saem time the 20th Engineers assgined to the 1st Division opened the D-3 exit.
Once the beach exits were open, the engineers moved inland to specific areas where there were to clear enemy mines for the troops following. The 121st suffered more casulaties when it found itself in the middle of German counterattack in the Vierville, area on the morning of D+1.
Tools of the Trade
All engineer units that took part in the invasion, regardless of echelon, used the following equipment:
Primacord
Primacord looks like yellow clothesline, but it contains a central core of explosive. When set off with a blasting cap the explosion travels along the Primacord and simultaneously detonates anything it is connected to. Primacord came in 50, 100 and 200 foot sections on wooden reels. Some demolition specialists connected several spools of Primacord together into a long chain and wound it onto DR-8 communications wire reels in 500' lengths.
Block, Demolition, C-2 (Compostion C4)
This was the main explosive used to destroy beach obstacles. Eight blocks of C-2 were packed into each satchel. C-2, a form of plastic explosive, was issued in 2 1/4 lb blocks. These satchels were designed to be blown up with their contents so little effort was expended in their material or construction.
M-1 Friction Ignitor
The M1 holds the time fuse in place by teeth inside the fuse lighter. These teeth are inclined to permit time fuse to enter, but prevent its removal except by force. A loop or handle is provided at the closed end of the igniter to aid in ignition. To prevent pulling the fuse igniter from the fuse, which will cause an air gap between the fuse end and the igniter, hold the body of the igniter in one hand and pull the igniter wire with the other. If any doubt exists as to whether the fuse is burning and the length of the fuse will permit the time, pull the fuse igniter off the fuse by force immediately after pulling the igniter wire to verify time fuse is burning. The Fuse Lighter was introduced before the United States’ entry into WW II as an alternative means to igniting time fuse with a match (the most commonly used method of the time). While not weatherproof, it was more reliable and windproof than a match. By 1945 the M1 was in the process of being replaced by the M2 fuse igniter. A reliable igniter as far as function goes, but not completely weatherproof and therefore unreliable in inclement weather. In the earliest Army demolition manuals, employment as a firing device is shown with short lengths of time fuse.
This is a chemical delay igniter, very similar if not designed from the British No. 10. The colored strips indicate the nominal delay times for each firing device.
Lighter, Fuse, Weatherproof, M-2
There were two types of fuse lighters used during the invasion. The standard M-1 ignitor was prone to failure if it got damp. An improved M-2 lighter was available, but only in limited quantities. Most of the waterporrf ignitors did not reach the demo teams until a few days before the landing. Once the "T" -shaped handle was pulled, the ignitor started a short length of safety fuse burning. Normally the time delay was two minutes, but the standard fuses made for Omaha were 8- second, 22- second, and 45- second delays. Once the fuse was ignited, it took the specified time for the dalme to reach a blasting cap (a small metal tube filled with sensitive explosive). When the blasting cap went off, it detonated the Primacord it was taped to. Designed during the Second World War, this is a fairly standard type pull switch. It likely owes a lot of the design to the British No. 1 Mk. I Switch. Remained in service and production for many years.
15 Second Delay Friction Detonator
Friction Tape
Friction Tape is a water-resistant adhesive tape used to insulate exposed electrical conductors. The tape is comprised of a high-quality cotton fabric coated with an electrical-grade rubber adhesive. It is designed to provide mechanical protection against abrasion and cut-through for cable and wire splices and connections insulated with rubber electrical tape.
Block, Demolition, M-2 Tetryol
Tetryol is a High Explosive composed of 75% Tetryl and 25% TNT. Tetryol is a high explosive bursting charge, and is used as a demolition explosive, a bursting charge for mines, and in artillery shells. The explosive force of tetrytol is approximately the same as that of TNT. It may be initiated by a blasting cap. Tetrytol is usually loaded by casting.
Tetryol was issued in 2 1/2 lb blocks linked together by a single length of Primacord. Wach 15 lb chain of 8 tetytol blocks was issued in a cloth bag. One 15 lb satchel charge of tetryol was used to blow up each hedgehog obstacle.
All of these photos are of reproduction equipment made by one of our members, Brian Lyles.