D-Day from Wikipedia
Probably the best summary of the action at Omaha beach.
https://en.wikipedia.org/wiki/Omaha_Beach
Relevance to Hex Command Mechanized
" ... Weakened by the casualties taken just in landing, the surviving assault troops could not clear the heavily defended exits off the beach. This caused further problems and consequent delays for later landings. Small penetrations were eventually achieved by groups of survivors making improvised assaults, scaling the bluffs between the most heavily defended points. By the end of the day, two small isolated footholds had been won, which were subsequently exploited against weaker defenses further inland, thus achieving the original D-Day objectives over the following days..."
The German defensive preparations and the lack of any defense in depth indicated that their plan was to stop the invasion at the beaches.[3]
About the Defenders
Four lines of obstacles were constructed in the intertidal zone. The first, a non-contiguous line with a small gap in the middle of Dog White and a larger gap across the whole of Easy Red, was 250 m (270 yd) out from the highwater line and consisted of 200 Belgian Gates with mines lashed to the uprights.
30 meters (33 yd) behind these was a continuous line of logs driven into the sand pointing seaward, every third one capped with an anti-tank mine. Another 30 meters (33 yd) shoreward of this line was a continuous line of 450 ramps sloping towards the shore, also with mines attached and designed to force flat-bottomed landing craft to ride up and either flip or detonate the mine. The final line of obstacles was a continuous line of hedgehogs 150 meters (160 yd) from the shoreline. The area between the shingle bank and the bluffs was both wired and mined, and mines were also scattered on the bluff slopes.[4][5]
Coastal troop deployments, comprising five companies of infantry, were concentrated mostly at 15 strongpoints called Widerstandsnester ("resistance nests"), numbered WN-60 in the east to WN-74 near Vierville in the west, located primarily around the entrances to the draws and protected by minefields and wire.[6] Positions within each strongpoint were interconnected by trenches and tunnels.
German Artillery at the Cliff Area
As well as the basic weaponry of rifles and machine guns, more than 60 light artillery pieces were deployed at these strongpoints. The heaviest pieces were located in eight gun casemates and four open positions while the lighter guns were housed in 35 pillboxes. A further 18 anti-tank guns completed the disposition of artillery targeting the beach. Areas between the strongpoints were lightly manned with occasional trenches, rifle pits, and 85 machine-gun emplacements. No area of the beach was left uncovered, and the disposition of weapons meant that flanking fire could be brought to bear anywhere along the beach.[7][8]
The focus of the main naval bombardment was then switched to the beach defenses, and at 06:00, 36 M7 Priest howitzers and 34 tanks that were approaching the beach on LCTs began to supplement the naval guns. They were joined by fire from ten landing craft-mounted 4.7-inch guns and the rockets of nine Landing Craft Tank (Rocket), the latter planned to hit as the assault craft were just 300 metres (330 yd) from the beach.[26]
Boats Approach Shore
As the boats approached to within a few hundred yards of the shore, they came under increasingly heavy fire from automatic weapons and artillery. The force only then discovered the ineffectiveness of the pre-landing bombardment. The bombers, facing overcast conditions, had been ordered to implement a pre-arranged plan to compensate for decreased accuracy. The center of targeting was displaced inland to assure the safety of the landing allied troops. As a result, there was little or no damage to the beach defenses.[35]
Burning Grass Obscures Defender View
Where the naval bombardment set grass fires burning, as it had at Dog Red opposite the Les Moulins strongpoint, the smoke obscured the landing troops and prevented effective fire from being laid down by the defenders.[39] Some sections of G/116 and F/116 were able to reach the shingle bank relatively unscathed, though the latter became disorganized after the loss of their officers
The second wave was larger, and so the defenders' fire was less concentrated. The survivors of the first wave were unable to provide effective covering fire, and in places the fresh landing troops suffered casualty rates as high as those of the first wave. Failure to clear paths through the beach obstacles also added to the difficulties of the second wave. In addition, the incoming tide was beginning to hide the remaining obstacles, causing high attrition among the landing craft before they had reached the shore. As in the initial landings, difficult navigation caused disruptive mislandings, scattering the infantry and separating vital headquarters elements from their units.[49]
Along with the infantry landing in the second wave, supporting arms began to arrive, meeting the same chaos and destruction as had the rifle companies. Combat engineers, tasked with clearing the exits and marking beaches, landed off-target and without their equipment.
Many half-tracks, jeeps and trucks foundered in deep water; those that made it ashore soon became jammed up on the narrowing beach, making easy targets for the German defenders.
Most of the radios were lost, making the task of organizing the scattered and dispirited troops even more difficult, and those command groups that did make the shore found their effectiveness limited to their immediate vicinity. Except for a few surviving tanks and a heavy weapons squad here or there, the assault troops had only their personal weapons, which, having been dragged through surf and sand, invariably needed cleaning before they could be used.[57]
Breakthrough
The key geographical features that had influenced the landings also influenced the next phase of the battle: the draws, the natural exits off the beaches, were the main targets in the initial assault plan. The strongly concentrated defenses around these draws meant that the troops landing near them quickly became incapable of carrying out a further assault. In the areas between the draws, at the bluffs, units were able to land in greater strength. Defenses were also weaker away from the draws, thus most advances were made there.[63]
The other key aspect of the next few hours was leadership. The original plan was in tatters, with so many units mislanded, disorganized and scattered. Most commanders had fallen or were absent, and there were few ways to communicate, other than shouted commands. In places, small groups of men, sometimes scratched together from different companies, in some cases from different divisions, were "...inspired, encouraged or bullied..."[58] out of the relative safety of the shingle, starting the dangerous task of reducing the defenses atop the bluffs.
Between 07:30 and 08:30 elements of G/16, E/16, and E/116 came together and climbed the bluffs at Easy Red, between WN-64 (defending the E-1 draw) and WN-62 (the E-3 draw). At 09:05, German observers reported that WN-61 was lost, and that one machine gun was still firing from WN-62. 150 men, mostly from G/16, having reached the top hampered more by minefields than by enemy fire, continued south to attack the WN-63 command post on the edge of Colleville.
Meanwhile, E/16, led by Second Lieutenant John M. Spalding and Captain Robert L. Sheppard V, turned westward along the top of the bluffs, engaging in a two-hour battle for WN-64. His small group of just four men had effectively neutralized this point by mid-morning, taking 21 prisoners—just in time to prevent them from attacking freshly landing troops.[71]
On the beach below, the 16th RCT commander, Colonel George Taylor had landed at 08:15. With the words "Two kinds of people are staying on this beach, the dead and those who are going to die – now let's get the hell out of here!"[72] he organized groups of men regardless of their unit, putting them under the command of the nearest non-commissioned officer and sending them through the area opened up by G/16.
By 09:30, the regimental command post was set up just below the bluff crest, and the 1st and 2nd battalions of the 16th RCT were being sent inland as they reached the crest.[73]
Beachhead
Where vehicles were landing, they found a narrow strip of beach with no shelter from enemy fire. Around 08:30, commanders suspended all such landings. This caused a jam of landing craft out to sea. The DUKWs had a particularly hard time of it in the rough conditions. 13 DUKWs carried the 111th Field Artillery battalion of the 116th RCT; five were swamped soon after disembarking from the LCT, four were lost as they circled in the rendezvous area while waiting to land, and one capsized as they turned for the beach.
Two were destroyed by enemy fire as they approached the beach and the lone survivor managed to offload its howitzer to a passing craft before it also succumbed to the sea. This one gun eventually landed in the afternoon.[79]
Aftermath
The foothold gained on D-Day at Omaha, itself two isolated pockets, was the most tenuous across all the D-Day beaches. With the original objective yet to be achieved, the priority for the Allies was to link up all the Normandy beachheads.[95] During the course of June 7, while still under sporadic shellfire, the beach was prepared as a supply area.
Surplus cargo ships were deliberately sunk to form an artificial breakwater and, while still less than planned, 1,429 tons of stores were landed that day.[96]
With the beach assault phase completed the RCTs reorganized into infantry regiments and battalions and over the course of the next two days achieved the original D-Day objectives.
On the 1st divisional front the 18th Infantry Regiment blocked an attempt by two companies from the 916th and 726th Grenadiers to break out of WN-63 and Colleville, both of which were subsequently taken by the 16th Infantry Regiment which also moved on Port-en-Bessin.
The main advance was made by the 18th Infantry Regiment, with the 3rd battalion of the 26th Infantry Regiment attached, south and south-eastwards.
The heaviest opposition was encountered at Formigny where troops of the 2nd battalion 915th Grenadiers had reinforced the headquarters troops of 2nd battalion 916th Grenadiers. Attempts by 3/26 and B/18 with support from the tanks of B/745 were held off and the town did not fall until the morning of June 8.
The threat of an armored counterattack kept the 18th Infantry Regiment on the defensive for the rest of June 8. The 26th Infantry Regiment's three battalions, having been attached to the 16th, 18th and 115th Regiments the previous day, spent June 8 reassembling before pushing eastwards, forcing the 1st battalion of the German 726th Grenadiers to spend the night extricating itself from the pocket thus forming between Bayeux and Port-en-Bessin.
By the morning of June 9 the 1st Division had established contact with the British XXX Corps, thus linking Omaha with Gold.[97]
https://upload.wikimedia.org/wikipedia/commons/thumb/5/57/Omaha_Beach_Nowadays.jpg/440px-Omaha_Beach_Nowadays.jpg