First model tests of car carrier powered by wind

With concept testing, the research project Wind-Powered Car Carrier has entered a new phase. The project aims to develop a sailing vessel that can transport about 6000 cars across the Atlantic. Such a ship is to reduce energy consumption by eighty to ninety per cent compared to conventional vessels.

Designing and testing sailing cargo ships requires completely new calculation tools to be developed. The model tests were performed in SSPA Sweden’s Towing Tank to validate the computations. The results will be used to optimise the design of the rig, hull and appendages. The research project is led by Wallenius Marine, with the Royal Institute of Technology (KTH) and SSPA as partners.

As part of the research project new simulation tools are developed, for example to model how the forces and moments from the wing sail affect the vessel. This is solved by performing numerical flow calculations (Computational Fluid Dynamics, CFD). Upwind sailing with tacking, that is when sailing vessels cannot keep a straight course towards the target, also needed to be implemented. CFD is also used to investigate which hull appendage can be effective for such a vessel.

Validation

The results from the advanced calculations and computer tests must then be validated and therefore physical model tests was performed in SSPA´s Towing Tank. Model testing is an important tool in the process of developing ships and assessing their performance and without the model tests, the risk is that the project will sub-optimise the design in some respects.

‘We may think that we achieve maximum speed with a certain height on the rig, but then notice when sailing that we must compensate too much with the rudder because the side forces are too large. Then we have not reached an optimum,’ says Sofia Werner, Senior Researcher & Manager Strategic Research Hydrodynamics at SSPA.

Author: Mariska Buitendijk

Mariska Buitendijk is one of SWZ|Maritime's journalists as well as the magazine's copy editor.