By Mike Cecil, Head of Military Heraldry and Technology, Australian War Memorial.

After the Second World War, the Australian Army continued to use the locally-built tracked carriers, even deploying them during the Korean War. However, their open topped design and thin armour in particular rendered them unsuitable for the modern battlefield, and a more modern replacement was sought.

Two vehicles in particular looked promising: the British FV432 Armoured Personnel Carrier and the American M113 APC. Both were fully enclosed, well armoured and had an amphibious capability. They were both powered by petrol engines with automatic transmissions.

In late 1962, two FV432 prototype vehicles, and two production model M113 APCs arrived in Australia, and trials commenced at 5 Tropical Trials Unit at Innisfail, Queensland. There were two main phases: the hot-wet trials conducted around Innisfail and Tully, and the hot-dry trials conducted around Mt Isa, in western Queensland. Within these phases were a series of specific performance trials, including the effects on the vehicles when left in long-term jungle storage, floatation and swamp traversing trials, and beach trials. All the vehicles were driven from Innisfail to Mt Isa and return as part of the durability and automotive trials, a round trip of nearly 2500 kilometres over varying terrain.

It soon became evident that the M113 was the vehicle that was more suitable for Australia’s needs. It offered superior traction and lower ground pressure, resulting in better performance over soft and swampy ground: precisely the type of ground likely to be encountered in South East Asia.  There were a few areas where the trials had highlighted a need for improvements, such as in the interior padding and increased ventilation when closed down. By this time, the manufacturer, FMC, had developed a diesel powered version, designated the M113A1, and it was this version, complete with the Australian modifications, that was ordered for the Australian Army.

The first bulk consignment of the M113A1 arrived in early 1965, the first of 815 vehicles in several variants to be acquired by Australia.  By May, Australia was providing ground forces to South Vietnam, including a troop of APCs. The M113A1 was a real asset in Vietnam, as it was able to transport troops into very difficult country. Armed with a single .50-inch machine gun attached to the commander's cupola, experience soon demonstrated that the commander was very exposed. A ‘field modification’ saw the installation of armoured shields, and soon after, twenty Model 74C turrets were procured as an interim measure for APCs serving in Vietnam. While armed with twin .30-inch machine guns and affording commanders some protection, they were very cramped and lacked good all round visibility when closed up.

The turret which offered more promise was the Cadillac Gage Company's T50 turret.  Although there were some criticisms, the T50 turret was considered a definite asset, and it was subsequently fitted to most Australian APCs.  

Today, the M113 family still provides the mainstay of Australia’s tracked vehicle fleet. They are undergoing a significant upgrade including stretching the hull, new turrets, drive trains, tracks and suspensions. Arriving at a final design has been a significant cooperative effort between Army, DMO and industry, and the results of that effort will serve the Australian Army for many years to come.