Additive Manufacturing: The American Corvus Published Sept. 5, 2024 By Lt Col Bryson Ayers Wild Blue Yonder--Maxwell AFB -- Additive Manufacturing: The American Corvus Mark Twain said “History never repeats itself, but it does rhyme”. Through this lens we can compare the Roman navy’s inventive corvus and the potential American use of additive manufacturing. Though 2,280 years separate these two technological innovations, they are not historical repeats, they rhyme. The problems they solve are different, yet the solutions they create share roots in timing, ingenuity, and Great Power competition. As global tensions rise, the United States has much to gain in the present from a study of the past. In 261 BC the Romans faced a problem. They were three years into a war with Carthage fighting for control over Sicily and the Mediterranean and needed a new strategy. The Romans up to this point had fought the war solely as a land power, but to wrest control of Sicily from the maritime Carthaginians they needed a navy. The problem was that they had no warships, no maritime tradition, and no true experience in naval warfare. Throughout their history the Romans built their national strength through land-based conquest. The merchant Carthaginians were their marital opposites. They used Carthaginian led mercenaries to fight on land but focused on protecting their maritime interests and sea lines of communication through a large, well built, well led, and superiorly trained navy. Despite Rome's disadvantages at sea, one year after the decision to build a navy, Rome miraculously defeated the superior Carthaginian fleet at the battle of Mylae. The victory doesn’t come through superior seamanship, better built warships, or crafty admiralship. They win the battle of Mylae through a technological innovation: the corvus. The corvus is a counter-weighted spiked plank the Romans used to board Carthaginian warships. Virtually turning naval warfare, which depends on years of training and expert ship building, into something resembling a fight on land. The corvus allowed Roman ships to immobilize their opponents. Upon employing a corvus, Roman soldiers board enemy vessels, decimating their lightly armed, poorly trained (for hand-to-hand fighting) opponents. In an instant the corvus changes the game. The Carthaginians no longer have supreme command of the sea. The corvus helps the Roman fleet hold-off and eventually defeat the superior Carthaginian fleet, but the corvus at the same time does not erase Rome’s maritime inexperience. Romans still display poor training and poor leadership at sea and the corvus introduces new dangers. Roman ships are now top heavy and more susceptible to rough seas caused by storms. This, combined with poor seamanship resulted the Romans catastrophically losing three massive fleets in six years. However, the Romans learn through trial and error. Use of the corvus provides time to improve their ship building, seamanship, and admiralship. As their capabilities at sea increase the Romans eventually discard the corvus and destroy the Carthaginian fleet using their superior skill and ships at the Battle of Aegates Islands. The Roman victory at sea ends the First Punic War decidedly in their favor. Today the United States faces a problem. We are in global competition with China over the shape of international order. Shall it continue to be the rule-based order we helped create, or an international system dominated by Chinese economic and military coercion? Though the United States holds the edge in both military might and economic power, over the last few decades we have ceded our industrial capacity to China in favor of cheaper goods produced by exploited Chinese labor and low environmental standards. According to an action plan published by the Department of Defense the United States, and especially the DOD, are almost completely dependent on foreign governments for large casted and forged products used for weapons and spare parts. If the United States enters a protracted war with China, we cannot expect to win if our own livelihood depends on our Chinese foe’s industrial might. To win we must rebuild the manufacturing dominance we once enjoyed. Re-building a capability we let atrophy over decades will not happen overnight. In the meantime, we need to bridge the gap with our own version of the Roman corvus. Additive manufacturing (better known as 3D printing) will be the American corvus. Additive manufacturing is the process of building objects through bonding materials layer-by-layer until one achieves the desired shape and strength. There are different methods and processes from ceramic slurries to electron beam powder bed to wire arc welding. There is also a hybrid process where a machine produces an object through layer-by-layer bonding while simultaneously subtracting small parts of material making a stronger microstructure. In many cases additive manufacturing builds geometry impossible for traditional casting and forging, hence can build even better tools and parts. Most important for the military, additive manufacturing has the potential to simplify logistic supply chains. Spare parts are critical to any sustained mechanized operation. And while maintainers can make their best guess it is impossible to accurately predict which parts will break and which parts will not. Instead of guessing which parts should fill the limited cargo space, imagine bringing an additive manufacturing machine and a couple pallets of powder or welding wire and then “printing” what you need when you need it. Like the corvus, additive manufacturing initially sounds like a panacea that wipes away our manufacturing disadvantage. The corvus was not a cure all for Roman naval might and additive manufacturing also has some inherent disadvantages. The process of bonding layers provides some advantage in geometry but also micro-structural weakness even with the hybrid process. Because of this microscopic weakness additively manufactured parts are more vulnerable to failure from the strain of high intensity operations. Furthermore, additive manufacturing needs a stable environment, skilled operators, and a dependable power source, which is still susceptible to the supply chain difficulties experienced by the rest of American industry. Additive manufacturing is no panacea. We still need to fix our underlying industrial weaknesses, but like the corvus additive manufacturing mitigates risk. The Department of Defense can print bombs, tools and with a little more risk it can print airplane parts. To win a protracted war with China, we need to re-build our industrial base, but in the meantime invest in and use additive manufacturing technologies to bridge the gap. Suggested Reading: Department of Defense. Securing Defense-Critical Supply Chains. Washington DC: Department of Defense, 2022. Seth C. Jones. "The U.S. Defense Industrial Base Is Not Prepared for a Possible Conflict with China." Center for Strategic & International Studies, February 23, 2023. J.F. Lazenby. The First Punic War. Stanford: Stanford University Press, 1996. Lt Col Bryson Ayers is a 2024 Air Force Fellow at Oak Ridge National Laboratory and B-52H Weapons Systems Officer The views expressed in this article represent the personal views of the author and are not necessarily the views of the Department of Defense, the Department of the Air Force, Air University, or the Department of Energy and Oak Ridge National Laboratory.