1. Summary of Operations
a. The 121st Engineer Combat Battalion, less Company A, with the 112th Engineer Combat Battalion attached, landed on Omaha Beach as part of the 116th Infantry Combat Team, which was part of the First Infantry Division Landing Team. The first units of this Battalion to land were two platoons of Company "B" with Lieutenant Colonel Ploger, the Battalion Commander, and a small staff, from two LCM’s at 060710 B June 1944. These platoons were closely followed by an LCM containing one platoon of "B" Company and one platoon of "C" Company landing ten minutes later. Advance element of Battalion Headquarters landed from an LCL(L) at 060730 B. The landings were made under heavy mortar, artillery, and machine gun fire inasmuch as no infantry had proceeded the landing of the Engineers on Dog Green and part of Dog White beach. A direct artillery hit on the bow of the LCI(L) was made just as unloading began and many engineers became casualties as a result of the blast and following fire. It is estimated that 50% of this initial force were casualties, and 75% of the equipment was lost. Captain Holmstrup, Commanding Officer, Company "C", was killed as he left the landing craft. Our initial effort was to regrup our forces and to gather enough material on the beach to accomplish our missions. Some elements of the Battalion proceeded immediately inland and entered Vierville-sur-Mer at about 1000 B hours, cross country by way of the bluff overlooking the beach east of Vierville.
Two platoons of "C" Company landed on Easy Green beach from LCT’s at 061030 B hours with bulldozers and about one ton of explosives each. Remnants of Company "B" and Company "C" were then directed to exit D-1 to open it for traffic. It was necessary to wipe out several sniper positions before actual work could begin. Approximately 30 prisoners were taken in the ensuing action. At about 1200 B hours an officer patrol, formed in Vierville-sur-Mer and led by General Cota, Assistant Division Commander and containing Major Olson, Engineer Battalion Executive, Captain Bainbridge, ADE of 254th Engineers, Lieutenant MacAllister, Engineer Battalion Adjutant, and others, proceeded through the D-1 Exit from the rear before it was opened, rejoining the elements of the Battalion at work on the beach and beach exit. The wall blocking the beach exit D-1 was breached with an external charge of 1100 lbs of TNT. The resultant vehicles. Company "B" remained on the beach to complete opening of the beach exit ant to clear the road to Vierville-sur-Mer. These missions were accomplished by 062100 B hours. Meanwhile Company "C" was ordered to clear transit area #1 west of Vierville-sur-Mer, which mission was about 50% completed that night. Company "C" bivouaced in transit area # 1, "H&S" and "B" Company bivouaced just south of Vierville. At 070530 B June 1944 the enemy attacked our positions from the south. The elements of the Battalion withstood the attack until the arrival of Rangers supported by tanks at about 1030 B hours. We then set up a defensive line for protection of Division CP along the east-west road through Vierville. Captain Humphrey, Commanding Officer, Company "B", was wounded while leading a part of Company "B" out the assembly area. At 071600 B hours Company "C" continued with their mission of cleaning transit area # 1, which was completed at 071900 B hours. Company "A" landed with the 115th Combat Team, the leading platoon landing at 062300 B hours. Company "A" supported for the forward movements of the 115th CT by opening lines of communication behind their leading elements. While passing through Saint-Laurent-sur-Mer, Company "A" came under fire of some snipers, at which time Captain Martin, the Commanding Officer, was wounded and evacuated. Company "A" joined the Battalion the evening of 7 June. Company "C" on the morning of 8 June cleared the town of Vierville-sur-Mer of rubble caused by artillery bombardment during the previous evening. Company "A" cleared the road leading to Grandcamp on 8 June.
The 112th Engineer Combat Battalion, attached to the 116th CT for the landing, reverted back to unit control on 7 June 1944.
b. The Advance to and Crossing of inundated area, Capture of Isigny, and the Advance to the River Elle.
Each infantry regiment in this phase of operations was supported by engineers who cleared roads to their forward elements. As soon as Isigny was captured the C Company bulldozer was dispatched there and cleared the road through the town which had been severely damaged by aerial and artillery bombardment. Company A supported the 115th Infantry in crossing the inundated area by building ten improvised foot bridges using assault raft equipment, pneumatic floats, and bridge timbers. The 254th Engineers supporting this Battalion constructed four short tread way bridges on the road from La Cambe to Douet, and also constructed a 40 foot double single Bailey Bridge at 473847 on the Isigny-Carentan road. Our Battalion continued to support the advance of the infantry south of inundated area to the River Elle with clearance and maintenance of routes of communication. Our first water point was established at 610907 and opened at 1900B hours on 9 June 1944.
c. Defense of the Elle River.
On reaching their objectives short of the Elle River, the Infantry consolidated their positions for defense. This Battalion furnished fortification material and mines to the infantry by establishing forward dumps immediately in rear of their front lines positions. On the night of 10 June Company C prepared bridges over the River Elle at 522743, 537733, and 526738 for demolition to protect the right flank of the Division, and assisted the S&P Platoon in preparing a road block at 536733. Company A on 11 June prepared road blocks of AT mines at cross roads in vicinity of Moulin Eveque and St. marguerite l'Elle. Company C assisted Company E of the 175th Infantry in crossing the Vire River at 477820 with assault boats the morning of 12 June.
d. Drive to the Vire, Villiers Fossard, Couvains Line.
Company B supported the attack of the 116th Infantry to capture Couvains and St. Clair sur l'Elle by cleaning and repairing roads on their axis of advance. Company C performed the same mission for the advance of the 175th Infantry south of Noon sur Elle. Waterpoints and engineer dumps were moved forward behind the advancing infantry.
e. Initial Defense of Vire, Villiers Fossard, Couvains Line.
As soon as the 175th and 116th Infantry reached their objectives, Company B and Company C established forward dumps of fortification material behind leading elements. Clearance of roads was extended to secondary roads. bridges and roads were reconnoitered. Infantry was assisted in preparing road block and constructing wire obstacles.
f. Engineer Battalion in the Line as Infantry.
At 181230B June 1944 a request was received from Division to clear out a nest of snipers at 526683. Two platoons of Company C were dispatched to reduce this strongpoint. The initial force proved inadequate for the mission and A Company plus a platoon of Company B was ordered to reinforce the elements of Company C. The piece meal attack on the 18th was unsuccessful so a coordinated attack was prepared for the morning of the 19th, to be supported by two tank destroyers, artillery fire and mortars from the 115th Infantry. Our troops advanced approximately 300 yards under heavy mortar and artillery fire. It was then apparent that this strongpoint was part of the enemy main line of resistance. The positions reached by our attacking troops proved to be untenable and they withdrew to a position slightly in advance of the line of departure. At 200700B June the 3rd Battalion 115th Infantry attacked the strongpoint from our let flank with elements of our Battalion holding in our present position. The attack was spearheaded by an engineer-tank-infantry team. The mission of our engineers (Company B) was to blow gaps in hedgerows to permit passage of tanks. Gaps blown with two 25 lb external charges were not entirely satisfactory, though the tank attack progressed further than that of the infantry. The infantry did not clear the enemy from the front of our positions. Our troops remained in position and organized the defense coordinating with the 175th Infantry on the right and the 115th Infantry on the left. The 115th Infantry relieved this Battalion from its defensive position 232200B June. The 1121 Engineer Group which had been in direct support of the Division since 7 June was replaced on 20 June by the 1115th Engineer Group. The 82nd Engineer Combat Battalion, a unit of the 1115th, Began closely supporting the 121st Engineer Combat Battalion on that date.
g. Continuation of the Defense of the Vire, Villiers Fossard, Couvains Line.
Upon being relieved from front lines, this Battalion took over normal engineer work in support of the infantry in setting up their defenses. Roads were cleared and repaired. New water points were established at 541728 ant the old WP at 568755 was taken over by the 82nd Engineers. Company C constructed a splinter proof shelter for Division Headquarters. Company A and Company C assisted the 115th and 116th Infantry in digging in their CP's. Company A constructed a dugout for G-4. On 26 June Company B practiced the use of engineers in the engineer-tank-infantry team assault through hedgerow country, using two 50 lb external charges, which proved very satisfactory, with the exception of the heavy load the engineer soldier was required tocarry. On 27 June Company B cleared hedgerows for anti-tank fields of fire in the vicinity of Couvains. A road leading through the 175th sector was xxx from enemy observation by Company C. Company A and Company C also cleared gaps in hedgerows for fields of fire for anti-tank weapons. Body traps laid by our troops were cleared by Company C in the 175th sector. Company A supported the attack of the 115th Infantry to capture Villiers Fossard, clearing rubble from the town and cleared roads of Teller-mines. A large number of cattle were buried with the use of bulldozer. As soon as the infantry captured Villiers Fossard, Company A assisted them in establishing their defense by furnishing fortification material and lading in construction of road blocks.