Camp Colt to Desert Storm: The History of U.S. Armored Forces

6. Marine Corps Armor Operations in World War II

6 Marine Corps Armor Operations in World War II Joseph H. Alexander The Pacific War had several crucial turning points: Midway the high tide of Japanese expansion; Guadalcanal, the first Allied offensive; and Saipan, which for the first time brought Tokyo within striking range of American B-29 bombers. Yet it was the bloody battle for Tarawa in November 1943 that proved to be the crossroads of the Pacific War in terms of armor tactics and technology. "Issue in doubt," reported the commanding general of Tarawa's landing force on the afternoon of D day, and indeed the battle hung in the balance for the first thirty hours. Tarawa was the one major battle in the Pacific after Guadalcanal that the Americans could have lost; it was the one full-scale amphibious assault that could well have been thrown back into the sea. Among a handful of decisive factors that swayed the balance was the innovative use of armor assets to overrun Japan's "Gibraltar of the Pacific."1 Tarawa represented not only the first combat employment of M4 Sherman medium tanks in the Pacific but also the initial availability of suitable sealift capability and landing craft to deliver them ashore during the critical first hour of the assault. Tarawa also represented the first tactical use of tracked landing vehicles (LVTs or amphibian tractors— "amtracs") to deliver assault troops over barrier reefs to the beachhead. The lessons of Tarawa were almost prohibitively costly: twelve of fourteen Shermans lost on D day, and ninety of 125 LVTs knocked out in the three-day operation. However, the Marines studied the battle with painstaking honesty, adapted quickly, and generated both the techno- 186 Joseph H. Alexander logical and doctrinal fixes necessary to facilitate the larger assaults that soon followed across the breadth of the Pacific.2 The Pacific War imposed entirely different requirements upon the armor arm than did the ETO. Imperial Japan's tank units lacked the mass, mobility, and firepower of Germany's heralded panzer divisions. The Japanese 47mm antitank gun, effective enough in cave warfare, could hardly compare with the deadly German 88mm gun. This moderate threat accounts for the reason why American forces could fight the entire Pacific War with light and medium tanks. If the U.S. M4 Sherman proved of increasingly marginal value in shoot-outs with heavier German tanks in Europe, the same combat vehicle ruled Pacific battlefields after Tarawa. The ETO was given strategic priority by the United States and its Allies. "Germany First" meant that Pacific armored forces typically had to fight with hand-me-down equipment and field improvisations until the America's ordnance productivity peaked in 1944. However, the principal difference between armored operations in the two theaters was a matter of geography: the vast oceanic expanses and small islands of the Pacific versus the large continental battlefields of Europe and Africa. Japan's concentric rings of fortified islands required strong naval, air, and amphibious forces to overcome. Because amphibious assaults occur in a prohibitive environment involving the risky buildup of combat power from ground zero and demand extraordinary cooperation between naval, air, and ground commanders, they are frequently described as the most difficult of military operations. As at Tarawa, armored forces would prove decisive in many of the epic amphibious assaults during the final two years of the war, but none of these successes came easily. Indeed, American commanders began the Pacific counteroffensive faced with three daunting requirements in the use of armor in amphibious operations: How to get assault waves of infantry ashore across barrier reefs under fire How to get tanks ashore early, in force How to modify armored vehicles for specialized missions against enemy fortifications (flame units and bulldozer kits, for example) Solving these problems satisfactorily demanded years of developmental work to produce combat vehicles adapted for the amphibious environment, specialized ships, and landing craft with which to deliver Armor Operations in World War II 187 them to the objective, as well as joint doctrine acceptable to each of the armed services. The Marines, increasingly identified with the amphibious assault mission, would take the lead. The Marine Corps entered World War II without a significant armor or cavalry tradition. A provisional tank platoon of M1917 light tanks served with the Marine Corps Expeditionary Force in the 1920s but folded after five years. Tanks were deployed to Culebra during the 1924 Fleet Winter Maneuvers, but they could...