Ihukenu Amphibious Truck

The Ihukenu (: Platypus), is a highly mobile amphibious military truck. Built by Zarman Land Systems between 1966 and 1991, these vehicles are operational with the Ngāti Tūmatauenga and a quantity of foreign armed forces to this day.

Design
The Ihukenu is a frameless vehicle with an all welded waterproof hull - the hull is the vehicle chassis. The engine is situated under the load deck in the rear of the hull and the gearbox with transfer box and differential forward of this. The load deck is open-topped with large drop down panels on either side and rear. Waterproof seals ensure that these will not leak when in the water. The cab has the driver's position in the centre, and a seat for a passenger on the left side of the cab or either side on some models. The cab can only be entered through roof hatches. The dropping side windows are emergency escape hatches.

The Ihukenu can carry 5 tonnes of stores, or tow 10 tonnes.

In the water it can be driven at about 6 knots by water-jet propulsion units.

The drive system, which includes the all-wheel drive, multiple gearboxes, and the water propulsion units, is complex and needed a lot of maintenance. When the amphibious qualities became unnecessary, it was common for the water jets to be removed to reduce weight and maintenance.

The Ihukenu's over-terrain capabilities come from the fact that the six-wheel-drive system lacks s, using simple bevel gears to transmit drive. A centre mounted no-spin differential allows a certain amount of slip between the two sets of wheels on each side of the vehicle on hard surfaces, but there is no allowance for rotational speed differences between front and rear. The centre no-spin unit allows the wheels on either side of the vehicle with most grip to drive when off-road. This has the effect of making the vehicle appear to crab (move from side to side) when negotiating muddy conditions, thus making the Ihukenu a true six-wheel-drive vehicle, with three wheels locked together and turning at the same speed.

However, this system causes "" in the transmission (inter-component stress) as all the wheels are forced to rotate at the same speed, which during cornering is impossible. This led to rapid wear and breakage of the tracta joints within the drive train if the vehicle was used on firm surfaces, such as tarmac or concrete – in off-road conditions, the natural 'slip' of a loose surface, such as mud or gravel, reduced wind up. This problem is of special concern for modern-day Ihukenu owners – to get a vehicle to a show requires moving it by low-loader or driving it on the road, risking damage to the transmission. Alternatively, the front and rear driveshafts can be removed, eliminating wind up at the expense of off-road capability.

During military use, the problem of transmission wind up was solved by laying out railway sleepers (s) in a grid on flat ground and driving over them on long road moves; this allowed the transmission to unwind.On more than one occasion, servicemen drove Ihukenus into car parks and used the kerbstones separating parking bays for the same purpose. Another problem with the transmission was that the vehicle was designed to be driven loaded. Driving the vehicle unloaded caused increased wear on the drivelines to the wheels as a result of the increased angle of mesh of the joints.

Military Operators

 * Theyka
 * Ngāti Tūmatauenga
 * Te Taua Moana o Theyka
 * Kitoko
 * Kitoko Ground Self Defense Force: 26 vehicles in service.

Civilian Operators

 * Theyka
 * Whakahautanga-a-iwi o Theyka (Civil protection and disaster relief)