The moldboard plow turns the soil over as it cuts a furrow. This brings nutrients in the soil to the surface, improves drainage, reduces the time and effort needed to prepare a field, and leaves a raised strip of earth on the edge of the furrow. These ridges of soil can build up considerably on the edge of a field if it is plowed in the same manner for a long time. In the Middle Ages, the advantages provided by the moldboard plow may well explain a good deal of the growth of Northern Europe, with its rich, heavy soils, and its rise over the older centers of development in Mediterranean and West Asian lands. Other effects of the moldboard plow continued into modern times, delaying and very nearly derailing the progress of the American invasion of Normandy in 1944 CE.
For many hundreds of years Norman farmers in the Cotentin Peninsula had cultivated small hedged fields, known as bocage. Centuries of farming had produced well-defined ridges of soil at the edges of these fields. These ridges were covered with a dense thicket of nettles and brambles, forming a barrier that averaged roughly 5 meters in height [16 feet]. The hedgerows served as fences marking the borders of the fields and orchards, and effectively prevented livestock from wandering. They also provided an effective barrier to armored vehicles and good cover for German defensive positions, protecting them against aerial observation.
Standard tanks could not break through the hedgerows. If the tanks rode over the hedges, they would expose their thinly armored underbellies to German fire while being unable to bring their guns to bear.
On D-Day [6 June 1944], men and equipment were brought close to the Normandy shore by Higgins boats, which had designs based on those of vessels used to bring equipment and personnel to swampy oil drilling sites around the Gulf of Mexico. The National WWII Museum in New Orleans grew out of a memorial to the hard-drinking Irish-American Andrew Higgins, his contributions to the Allied victory, and his enlightened employment policies.
After securing a foothold on the beaches, a process critically aided by snorkeled tanks that could make their way through the surf, Allied troops began to move inland. The portion of Normandy assigned to the British, near Caen, was mostly broad plains generally suitable for tanks, with a few bocage fields. The English made slow but steady progress.
The American attack, unprepared for the obstacles the hedgerow countryside presented, stalled in the bocage of the Cotentin. Though the characteristics of the landscape were not secret, plans to deal with the challenges it presented had not been made.
Sergeant Curtis Culin of the 2nd Armored Division’s 102nd Cavalry Reconnaissance Squadron is usually credited with solving the problem, though he said the idea came from a Tennessee hillbilly named Roberts, who asked “Why don’t we get some saw teeth and put them on the front of the tank and cut through these hedges?”
Most laughed at Roberts’ inquiry; Culin made prototypes in Normandy using metal from Czech hedgehogs deployed by Germans on the beaches. These Czech hedgehogs were basically oversized caltrops designed to hinder tanks and other armored vehicles.
General Omar Bradley was impressed by a demonstration of a modified Sherman tank bursting through a hedgerow. He ordered a major scale up. Soon thereafter nearly two-thirds of 2nd Armored Division’s tanks and tank destroyers were equipped with the hedge busting devices. Manufacturing was eventually shifted to the United Kingdom, where the modifications were called prongs. American forces benefited from the restoration of armored mobility.
The decisive factor in the American breakout from the Cotentin, however, was airpower: on 25 July 1944 approximately 1,500 American bombers dropped nearly 3,000 tons of bombs between Montreuil and Hebecrevon, northwest of Saint-Lô. Whole sections of the German defense lines disappeared, as well as a few foolhardy American officers who wanted to observe the destruction from a site that was too close to the German positions.
After the American breakout, the British continued their deliberate advance. The Americans and Poles raced to trap the German armies in France. Many of the Germans were eventually surrounded in the Falaise Pocket. Despite the escape of some Nazi forces, the Allies inflicted huge losses. Paris was liberated two days after the climax of the Falaise battle.
In the Pacific theater of war, a similarly effective field innovation was important in paving the way to victory. General George Kenney, educated in part at MIT, modified B-25 medium bombers, adding 10 fifty-caliber machine guns to each to turn them into aerial gunships that could still deliver bombs. Australian engineers implemented Kenney’s ideas.
The modifications were crucial to the overwhelming American victory in the Battle of the Bismarck Sea, which the Japanese needed to cross to reinforce their troops in New Guinea [March 1943]. The B-25s strafed the Japanese ships, killing crew, officers, and infantry passengers, before skip bombing them.
Shortly thereafter, when Kenney was visiting Washington D.C., his request to include the modifications in B-25s sent to him from the factory was met with derision by supply personnel from the Materials Division. They told Kenney such changes were “impractical” and would “disturb the balance of the airplane and make it almost impossible to fly.”
Kenney had the satisfaction of informing them that B-25s field-modified to such specifications had inflicted much of the damage in the Bismarck Sea. He also had the pleasure of watching General Hap Arnold order the men out of the room with an angry warning to “quit arguing.”
- There are a huge number of books on the Normandy campaign. Too many focus on one nation’s experience and contributions to the campaign. Antony Beevor’s D-Day: The Battle for Normandy avoids the common shortcomings of British writing on the Second World War, providing a more than usually balanced narrative with adept choice of anecdotes. It is far from the worst place to start on this topic.
- Omar Bradley prepared two autobiographies with substantial assistance: A Soldier’s Story and A General’s Life. The former is one of the two main sources for the movie Patton; the latter provides more details regarding the American high command during World War II, in part because it was prepared after restrictions about mentioning Ultra decoding had been lifted.
- Bruce Gamble’s Fortress Rabaul and Target Rabaul provide an overview of the Southwest Pacific theater of World War II with emphasis on the air campaigns.