Tests conducted in Europe have shown that a boat tail – a tapering protrusion mounted on the rear of a truck – leads to fuel savings of 7.5 percent. The fuel savings, which also means a cut in emissions, were realized by the boat tail dramatically reducing the drag caused by the lower-pressure effect that occurs in the wake of a vehicle.
The boat tail had already proved itself during wind tunnel experiments and computer simulations, in theory and using small-scale models. Now an articulated lorry fitted with a boat tail has also undergone extensive testing on public highways and borne the theory out. The lorry was driven for a period of one year with a boat tail of varying lengths and one year without a boat tail. The improved aerodynamics were dependent on the length of the boat tail, with the optimum length found to be two meters (6.5-feet).
The tests were carried out by the Platform for Aerodynamic Road Transport (PART), which is European group made up of scientists, road transport equipment manufacturers and shippers and carriers working together towards the aim of achieving a 20 percent reduction in fuel consumption and CO2 emissions in the road transport sector by 2020.
Trucks already sport a range of modifications designed to improve the aerodynamics of the vehicle, such as side panels, aerodynamic mudguards and mirrors, and roof deflectors. Of these only side panels are more effective at cutting fuel consumption (9 percent) so it’s hard to imagine we won’t be seeing trucks on the roads with a little extra junk on their trunks in the near future.