THE DEFINITIVE TRUCKING SITE

September 2008

Finding better ways to move payload is a trailer builder’s primary focus and every year our local trailer designers – as well as some operators – ‘reinvent the wheel’ and produce world-beating products that make all truck-lovers say: “Why didn’t I think of that?” Paul Collings finds two new designs that are South African firsts. 

Skeletal trailers are the backbone of ISO-container truck transport and a vital link in the multimodal logistics chain. While the road may be their natural workplace, it is the dockside that presents their toughest challenge. 

Kevin Martin owns a Durbanbased transport operation called Freightliner (nothing to do with the riveted beauties from the USA) which specialises in moving six and 12-metre shipping containers from Durban harbour to distribution depots around the city. 

“It’s all short-haul stuff,” he says, “and running empty containers back to the docks is an unavoidable reality of the job. No operator likes to run non-paying trips, especially when big rigs are involved. The fuel costs are onerous and it really doesn’t make sense having a rig capable of carrying a 35-ton load spending half its operational time carrying a fiveton load, which is what an empty container weighs.” 

This common trucking dilemma prompted Martin and Freightliner sub-contractor, Robin Nel, to put on their ‘Einstein caps’ to find a better way of delivering empty containers back to dockside from their respective off-load points.

“What we’ve designed is called a ‘micro-skellie’, a lightweight skeletal trailer built by Road Hog that can handle an empty 12-metre or two empty six-metre ISO containers. The beauty is the savings that come from the fact that it is drawn by a sub- 12-ton Mitsubishi Fuso 4x2 that has been converted from a rigid into a light-weight truck tractor,” says Martin. 

The total combination mass is around 11-tons and this means licence fees are way cheaper than a big rig – R14 000 per annum for the heavy combination and a mere R1 600 per year for the micro-skellie. What’s more, a driver only needs a Code-10 licence to pilot it. 

“We expect to reduce fuel consumption by at least 50% on these return trips and they’re far more maneuverable around the docks than their big brothers,” concludes Martin.

Reducing the fall-over risk

The tipper market is booming and local trailer builders are pushing out larger numbers of long-wheelbase side and sloper/end tippers, particularly for mining (mostly coal) applications. 

A primary design consideration with tippers is keeping a low centre of gravity, explains Duncanmec’s Cornell Dunn. “Typically, long sloper-type end tippers have a high centre of gravity when their hydraulic rams are fully extended and are relatively unstable, especially in uneven, windy terrain.” 

While side-tippers have a lower centre of gravity, the centre shifts to the right-hand side of the vehicle during the tipping action and this can be risky under certain topographical conditions. 

“We at Duncanmec have been developing an aluminium doubletipper that will drastically reduce the risk of trailer fall-over. This tough but light unit was designed by our MD, John Rivett-Carnac and is currently undergoing field tests with two leading tipper operations. The innovative design aims to help reduce fuel consumption while improving safety. As always, payload maximization is always at the heart of Duncanmec products and this unit is capable of carrying a payload of 33-ton.” 

Tipper buyers can see this vehicle up-close at the forthcoming Johannesburg International Motor Show starting November 1 at Nasrec.