Introduction
Aerodynamics have never really featured much is ship design. Hydrodynamics are the key source of drag; the hull?s contact with the water.
However ships that sail routes with the wind frequently on the bow pay quite a penalty for the drag created by above deck structures such as the cranes and particularly the accommodation block. Greenwave set out to examine methods of improving this drag penalty, thus saving fuel and emissions.
How it works
The first step was to model an actual ship superstructure and test it in the twisted flow wind tunnel at Auckland University. This identified where the real turbulence hot spots were. It is this turbulence that creates the drag.
Once identified, the team set about creating fairings with special profiles which, when placed in the hot spot areas, would smooth out the wind flows. Thus it was possible to improve the drag penalty simply by using modular fairings that could be fitted by the ships own engineers within a day or two and have an immediate payback on the next voyage.
Performance Parameters
Test have shown it is possible to reduce above-deck drag by at least 20% typically saving around 50 tons of fuel and 150 tons of CO2 per ship per year simply by fitting a low cost modular drag kit which is made from recyclable materials.
