Decisions about increasing the size of the Australian Main Battle Tank fleet always seems to be contentious because of counter arguments about whether the capability can be justified because they will never be used in combat, given their size and weight. This line of argument goes that since they cannot be deployed outside Australia, they are only useful on home soil – and by then it will be too late. Neither argument really stacks up.
True, they are massive beasts. The current 59 M1A1s in the inventory weigh about 60 tonnes each. The next crop of 71 M1A2 SEPv3 are a fraction more than 67 tonnes – so moving them anywhere takes quite a bit of planning. However, they can be transported on low-loaders, rail, on Navy’s LHDs – and at a pinch, and one at a time, in RAAF’s fleet of C-17 heavy lift transport aircraft. In the latter case this would not be done frequently as every landing with such a weight on board reduces the fatigue life of the aircraft.
The bottom line is that if they need to be deployed outside Australia then they can be. Heavy armour has been used effectively throughout the entire region, as Vietnam War and Second World War experience shows. While they are at their most devastating in flat open terrain – such as northern and eastern Europe and much of the Middle East – with careful handling they bring a massive amount of direct firepower and high levels of protection to most scenarios.
Because of their weight and size, careful note needs to be taken of infrastructure and ground conditions where they are to operate – particularly if they exceed the load limits of bridges and are wider than railway tunnels – but most of this is common sense and not much different to deploying commercial heavy machinery. A Caterpillar D-11 bulldozer is twice the weight of an M1A1 and they are used all over the world from the tropics to the Arctic.
Important considerations with MBTs are their good power-to-weight ratio and their low ground pressure. All Abrams tanks use a Honeywell gas turbine engine producing 1,500 horsepower – in Australia the local support company TAE has tweaked them to go a bit higher than that – and even for the heavier SEPv3 variant gives them good acceleration and top speed. They can also push through thick foliage and knock down trees, walls and the occasional building if they need to. Because of the width of the tracks, they have lower ground pressure than almost all wheeled vehicles, meaning they can cross a wide variety of terrains, climb steep slopes and so on.
Despite the difficulties of getting them there, heavy armour was used successfully in Afghanistan. Canada used Leopard 2 MBTs and the US Marine Corps deployed a company of 15 M1A1s to Helmand province in 2010. During one weeklong operation they worked closely with Australian Special Forces soldiers clearing a series of villages occupied by the Taliban.