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Some military expeditions require the combined skills and resources of two or more armed services to achieve an objective. Amphibious operations use armies to seize overseas objectives and the navy to get them there. In the past, the commanding general and admiral shared command, “each supreme in his own sphere.” Kings and governments expected them to work together to obtain victory, though cooperation could not be guaranteed.

Joint operations challenged leaders because generals and admirals did not understand their partner’s capabilities and limitations. In his book, The Influence of Seapower Upon History: 1660-1783, Alfred Thayer Mahan characterized such misunderstandings.

“The army thought that the navy might have beaten down stone ramparts ten feet thick; and the navy wondered why the army had not walked up the same ramparts, which were thirty feet perpendicular.”

Failed Joint Operations - Santiago de Cuba

In my book, Disaster on the Spanish Main, I discuss the inept command structure of the British attempt to capture Santiago de Cuba in 1741. A massive British expeditionary force had just returned to Jamaica from their failed siege of Cartagena. The two commanders Vice Adm. Edward Vernon and Maj. Gen. Thomas Wentworth then set their sights on Santiago. Wentworth wanted the navy to blast its way past Castillo San Pedro de la Rocha and land his troops inside the harbor. Vernon refused to risk his ships in the narrow channel under the castillo’s guns.

Without consulting the army, Vernon landed the troops at Guantanamo Bay, fifty miles east of Santiago. He expected the army to march across enemy territory, over forest trails with no draft animals then assault a castle. Once the general saw the terrain and the distance to be marched, he refused to budge. Instead of working through their differences, both commanders became obstinate and accused the other of sabotaging the operation. After the mission was abandoned some of the army officers sent a proposal to London. They begged that in future amphibious operations, “the chief command of the whole should be lodg’d in a single person.”

Tragic Joint Operations - Operation Cobra

In World War II, General Eisenhower managed to get unified command of the three combatant arms for the Normandy landings. Eisenhower, a big proponent of joint operations, once said, “When you put sea, ground and air power together, the result you get is not the sum of their separate powers. You multiply their powers, rather than add.” Under a single commander, Allied forces worked together more effectively but still had issues sorting out combined missions.

Target Box for Operation Cobra

To achieve a breakout in Normandy Lt. Gen. Omar Bradley planned to bomb part of the German defensive front. He wanted to drive into a void created by heavy bombing. Bradley plotted a “target box” just beyond a highway to be saturated by British and American strategic bombers.

During a planning session the general and air staffs disagreed about the direction of the air attack. Bradley wanted a parallel approach to the target box, so the bombers would not fly over his troops. The air commanders opposed the parallel approach because it jammed the planes into a narrow corridor. They argued for a perpendicular flight path that posed less risk for their crews. The meeting broke up without a clear understanding of how the bombers would make their runs. Without consulting Bradley, the air commanders later decided to attack the target box at a right angle to the front.

Operation Cobra achieved mixed results. The strategic bombers inflicted serious destruction, though not total, on the German defense. The benefit of the carpet bombing got offset by numerous short bomb loads dropped on friendly troops. The units making the attack suffered confusion and the loss of over 100 killed and nearly 500 wounded. Bradley’s penetration succeeded in breaking through but he swore off using strategic bombers ever again.

Successful Joint Operations - Fort Fisher

There have been notable examples of successful joint operations. During the Civil War the Confederates fortified the point of land at the entrance to the Cape Fear River. This fortification, Fort Fisher, had kept the vital port of Wilmington open to blockade runners. After an abortive attempt on Fort Fisher in December 1864, the Union organized a second attack in January.

Rear Adm. David Porter and Maj. Gen. Alfred Terry coordinated an amphibious landing north of the fort. The navy provided massive fire support against Confederate positions while Union troops came ashore on January 13. The ships shifted their fire to the fort as the army cut off the peninsula and made its approach. After a continual bombardment the army and a supporting force of marines assaulted the fort’s northern face. The troops penetrated the fort while communicating their progress with the navy. The ships kept shifting their fire ahead of the advance until the Confederates surrendered. Careful planning and communication produced a decisive Union victory against a formidable defensive position.

Naval Bombardment of Fort Fisher

Lessons

In sum, joint operations depend on each armed service understanding the resources, tactics and shortcomings of the others. The operational plan demands input from each service to involve joint assets to their fullest capability. A single unified commander should settle disputes and disagreements between services. During execution, all services must overcome systems incompatibilities to inter-communicate and keep the battle properly coordinated. When joint planning, communication and control come together the results can achieve the multiplicative effect Eisenhower described.

With the 75th anniversary of D-Day approaching, I want to reflect on a subject that people often misunderstand.

Operation Fortitude

After World War II ended, the public learned of Allied deception efforts to confuse the German high command. The most successful trickery disguised where the Allies intended to open the Second Front in western Europe. The coordinated hoax known as Operation Fortitude spread false information to convince Hitler and his generals that the D-Day landings would take place near Calais. British and American intelligence agents devised elaborate schemes to turn the Germans’ focus to the narrowest part of the English Channel and away from the Normandy beaches. Publicity surrounding General George Patton’s presence in southeast England and the staging of dummy vehicles and landing barges appeared to indicate an invasion of the northeastern French coast.  Double agents fed disinformation to German intelligence services that led them to fixate on the Pas de Calais sector.

Dummey Sherman tank
Inflatable model of a Sherman tank

Film clips of men inflating fake tanks and aircraft have made for good theater on recent TV shows. Commentaries by historians tout the success of Fortitude. It fooled the Germans! Because of that, Hitler positioned the bulk of his panzers and infantry forces near the Flanders coast. Even after D-Day, the clever deceptions persuaded the Germans to keep their panzers in the north and delayed their counter-attack in Normandy. Such comments lead viewers into thinking that without Fortitude the Germans would have reinforced Normandy and crushed the invasion.

I believe the recent hype over-states the importance of Operation Fortitude.

The Role of Uncertainty

Allied intelligence operations did succeed. The German high command thought the D-Day invasion would come in Flanders. However, this misconception did not significantly influence the Germans’ disposition of their forces, nor did it need to. Uncertainty dictated German defensive planning.

Rommel and von Rundstadt
German generals planning defense

Barring precise and firm proof of enemy intentions, something almost impossible to obtain, defenders must account for all enemy options. There are never enough troops to cover everywhere. Therefore, a defender looks at the terrain then deploys forces to block enemy avenues of attack. A sensible plan concentrates precious combat assets on the most dangerous avenue for two reasons. First, it’s a way to redirect the enemy to an area that is less threatening and/or easier to defend. Second, if the enemy does attack on the most dangerous route, the defender can commit the bulk of his forces at once.

German Defensive Planning

Map of Overlord
Map of Operation Overlord

Put yourselves in Rommel’s and von Rundstedt’s shoes then look at a map of the English Channel. Aside from being closer to England and offering a quicker channel crossing, Calais posed a greater threat than Normandy. Allied air cover could extend deeper and stay longer over the invasion area. In addition, a landing at Calais would put the Allied armies north of the Seine and Somme Rivers. Because of that, it provided a shorter and easier route into Germany. As a result, the Germans had to place their panzers in Northern France and Belgium to cover this Allied avenue. Otherwise, they would have invited disaster.

German defensive planning achieved some of its purpose. The Allies chose the safer avenue and landed on the Normandy coast. It took them three months of brutal fighting to reach Flanders, as opposed to landing there on D-Day.

Post D-Day Uncertainty

Panzer reserves
Panzer Reserves

Fortitude played a helpful though not a decisive role in slowing the German response to the D-Day invasion. Also it helped keep the panzer reserves away from Normandy. Again, uncertainty weighed more heavily on German thinking than false assumptions. It took Rommel and von Rundstedt only two days to perceive that the Normandy landings were a main effort rather than a feint. However, they could not rule out a possible second landing near Calais. Because of that, they could not commit their panzer reserves and leave Flanders uncovered. Either Hitler had to back-fill with reserves from the Russian front or contain the western Allies with the forces in France. He chose to hedge his bets in the west. The Germans bottled up the Allied invasion in hedgerow country for two months. By the time the Germans could disregard an invasion at Calais, their defense in Normandy had collapsed.

Summary

In conclusion, readers should be cautious about the claims of intelligence operatives who take credit for “deceiving the enemy.” Military strategists understand that enemy options have to be considered and resources allocated to cover each one. It’s uncertainty that forces planners to split forces, not a misreading of the situation. A good intelligence operation only needs to reinforce that uncertainty to achieve its purpose.

World War II Indirect Fire Weapons

Rifle Company mortar
60mm mortar

When asked to name indirect fire weapons used by infantry units, most people think of mortars. Yet, US Army infantry battalions in World War II fielded three indirect fire weapons. Each rifle company had two 60mm mortars, and the heavy weapons company employed six 81mm mortars. The third indirect fire weapon system surprises most people—the M1917A1 .30 cal. water-cooled heavy machine gun.

Heavy Machine Gun Team
M1917A1 Machine Gun Team

Wait! Aren’t machine guns direct fire weapons? Sure. The heavy machine guns served a crucial role in suppressing enemy weapons or mowing down enemy infantrymen with direct fire, especially in defensive situations. In offensive operations, machine guns had limitations on their direct fire role because advancing friendly infantrymen often masked their fire. The M1917A1 machine guns could overcome those limitations by using indirect fire techniques to shoot over the heads of friendly troops and pin down distant enemy positions.

What Is Indirect Fire?

What differentiates direct fire from indirect fire? In direct fire mode, a machine gunner uses a sight to aim at a target. He can adjust the sight to account for cross-wind and/or distance, but he still observes the target as he fires. In indirect fire mode, the gunner may not see the target. Instead he is given a direction of fire and a range to the target by an observer who has eyes on the enemy.

In order for an observer and gunner, working together, to place rounds on target, the weapon system must have 1) a mount calibrated for traverse and elevation and 2) a table of firing data.

The diagram below shows the machine gun and its mount. Just above the tripod, a traversing dial allows the gunner to swivel the direction of the gun left or right of center at a specified angle. The elevating arc sitting above the dial enables the gunner to raise the gun’s aim by a measured amount.

Water-Cooled Heavy Machine Gun
M1917A1 Machine Gun

The army field manual (FM) for the machine guns printed firing data to tell the gunner how far a round would travel at a given elevation of the barrel--assuming the ground was level. For instance, to hit a target at a range of 1,500 yards the gunner had to set an “angle of elevation” of 35 mils, or about 2o. The FM also printed formulas to tell a gunner how to adjust for targets on higher ground and how much to elevate the gun to clear the heads of friendly troops moving forward.

Infantry Observer

The observer had the harder job. In a tactical situation, he had to know his own location and the location of the M1917A1s, then he had to spot an enemy position. The observer either had to identify the enemy’s grid coordinates on a map or visualize an imaginary line from from the guns to the target. With a compass, protractor and some math, the observer calculated the initial azimuth and range from the guns to the target. Once the machine guns fired tracer ammunition at the target, the gunner had to spot the strike of the rounds and estimate how far off the target they landed. He then applied a couple more formulas and called back corrections to the gunners until the rounds hit the target. Requiring all that math and estimation while under fire, placed a huge burden on the observers.

Infantry Plotting Board

World War II Infantry Plotting Board
Infantry Plotting Board

The infantry observers’ lives got a whole lot simpler when the army issued plotting boards to the field in the summer of 1944. The plotting boards were fashioned with a clear plastic disk that rotated over a base with printed grid lines. The pivot point on the disk represented the position of the guns. The section sergeants, co-located with the guns, marked the observer’s known position on the disk using the grid lines on the base to correspond with map coordinates. When an observer called in an enemy target, he only had to tell the section sergeants the azimuth and estimated distance from his position to the target. Back at the gun position, the sergeants measured the angle and distance called in by the observer then marked the target position on the disk. The sergeant measured the line from the pivot point to the target position to determine the range and azimuth between the guns and the enemy. He gave that firing data to the gunners, so they could set proper direction of fire and elevation on the guns. After the guns fired spotting rounds, the observer only had to call back corrections as he saw it from his position. The sergeants with the plotting boards issued the corrected directions of fire and ranges to the gunners.

Conclusion

The heavy machine guns played an important role in the attack because they could employ indirect fire techniques. With the advent of the simple plotting boards the infantry battalion could get indirect fire from the mortars and heavy machine guns onto enemy targets more accurately and faster than before. You can read more about how World War II infantry units made use of the plotting boards in my book Battle Hardened.

Historians have spilled more ink about the Battle of Gettysburg than any other conflict in human history. Still, people often lose sight of the critical role artillery fire planning played in the attack against Cemetery Ridge.

Confederate Fire Support Plan

When General Lee decided to attack Cemetery Ridge on July 3, he fashioned a plan

Brig. Gen. Wm Pendleton
Confederate Artillery Chief, Brig. Gen. Wm Pendleton

that depended on a massed artillery preparation. He intended to have the artillery fire pave the way for Pickett’s, Pettigrew’s and Trimble’s infantry divisions. Yet, Lee’s plan fell short of its potential. Lee's Army had not developed the degree of centralized fire planning necessary to achieve his purpose. The army’s chief of artillery, Brigadier General William Pendleton, viewed his role as a logistics planner, not as a tactician. He only contributed to the fire support plan by tasking the batteries in Hill's and Ewell's Corps that faced the objective to join the bombardment. Responsibility for directing the artillery fire against Cemetery Ridge devolved upon Colonel Edward Porter Alexander who commanded the I Corps (Longstreet's) artillery reserve battalion. Alexander amassed enough guns to pound Cemetery Ridge. Eighty-four guns from I Corps, seventy-two guns from III Corps and another sixteen from II Corps would fire the preparation.

Col. Edward P. Alexander
I Corps Artillery Commander Col E. P. Alexander

The batteries deployed along Seminary Ridge that ran parallel to the objective on Cemetery Ridge. The guns had a broad sweep of the Union lines but the limited depth of the objective presented a challenge. The gunners needed precise range estimates and accurately timed fuses to strike their targets. Lee counted on the 172 guns to soften up the Union infantry and take out their supporting artillery. However, the Confederate fire support had one inescapable limitation. Lee had planned a frontal attack. The Confederate infantry had to pass through their own artillery batteries on the way to the objective. That meant the artillery could not suppress the Union guns during the infantry approach march and final assault.

Missed Opportunity

The Confederate fire support plan had another, needless, flaw. Neither Lee nor

Attack Against Cemetery Ridge
Confederate Attack Against Cemetery Ridge

Pendleton planned artillery fire to encompass the whole battlefield. More than 40 guns belonging to Ewell's II Corps stayed idle during the attack. Pendleton left them out of the battle because II Corps was not involved in the attack. This decision violated an important artillery precept to maximize the use of available fire support assets.

To make matters worse, the II Corps guns had the best position for suppressing the defenders on Cemetery Ridge. The Union defense resembled a fish-hook, anchored on Round Top in the south and Cemetery Hill in the north. The long dimension of the front ran north-south along Cemetery Ridge. The south-facing II Corps guns had a chance to rain devastating enfilade fire down the length of the objective. The gunners only had to align their guns with the ridge and not worry about the range. Their shells would land somewhere along the defensive front. Furthermore, these guns could keep firing throughout the infantry attack until the final push masked their fire.

Union Fire Support

MG Henry Hunt
Union Artillery Chief, Maj. Gen. Henry Hunt

In contrast, the Union chief of artillery, Major General Henry Hunt, supervised all the army’s guns. He even oversaw the allocation, positioning and targeting of the guns under the direct control of the corps commanders. Hunt arrayed his batteries from Little Round Top in the south to Cemetery Hill farther north. From these positions, Union artillery covered the valley separating the two armies with deadly interlocking fire. Hunt also trained his battery commanders to fire at a deliberate rate to conserve ammunition and preserve accuracy.

Artillery Battle

The effectiveness of the artillery fire on July 3, 1863 reflected the tactical expertise of the two artillery chiefs. The Confederates unleashed a concentrated and sustained bombardment but the massive preparation failed to blast a hole in the Union line. The gunners had difficulty setting the proper range on their guns. As a result, the shells mostly overshot the objective.

At first, the Union batteries returned fire, leading to an indecisive artillery duel. Union General Hunt intervened to stop the duel. He ordered his batteries to cease fire. He knew the upcoming infantry attack represented a greater threat and a more lucrative target for the Union’s remaining rounds. Across the battlefield, Colonel Alexander halted the Confederate preparation once ammunition ran low. This left the Confederate infantry to break the Union line on their own. A key piece of Lee’s battle plan had fallen short.

Artillery Fire at Gettysburg
Union Battery in Action

When the Confederate infantry divisions approached Cemetery Ridge, the Union guns inflicted appalling casualties with canister shot against the exposed infantry. Rather than stay put, one aggressive Union battery surged forward and flanked the Confederate formation. Their guns then shattered the attacking infantry with deadly enfilade fire. As the attack reached its decisive stage, the Union guns punished the Confederates with heavy losses.

To read a more detailed description of the assault on Cemetery Ridge, I invite you to read my previous publication, More Terrible Than Victory,

Conclusion

In sum, ineffective Confederate artillery fire planning squandered a chance to deliver a damaging blow to the Union position on Cemetery Ridge. This oversight allowed well-planned and well-managed Union artillery fire to cripple the assault.