The hull as a sail
Norway’s Vindskip re-shapes the tall hull of a PCTC ship to provide ‘sail assistance’ to a gas powered propulsion plant, offering 60% fuel savings and 80% lower emissions
Tucked away almost unnoticed in a corner of the Nor-Shipping exhibition earlier this year was a project for another wind-assisted cargo ship, but one which used neither sails nor kites.
Instead, the Vindskip (Wind Ship) uses its hull as a sail. Norwegian designer Terje Lade describes the ship as working in a similar fashion to a sailing vessel sailing close-hauled, just off the wind direction. But unlike a pure sailing ship, the Vindskip works in tandem with the ship’s propulsion, taking advantage of the apparent wind created by the forward motion. This, says Mr Lade, means that the sail provides a pull even sailing across the wind. "It will give you a positive pull in the direction of the ship more than 50%of the time, as an average, without doing anything," he said.
The idea, apparently came from Mr Lade’s interest in speed sailing, where vessels sailing close-hauled have recorded speeds of up to 52 knots in a 25-knot wind. And by using computer technology to optimise propulsion and wind speed in order to maintain a forward speed of around 18 knots, together with weather and wind data to select the optimum route, performance equivalent to a conventional cargo ship is said to be perfectly feasible, at a 60% saving in fuel, and thanks to the use of LNG as fuel, 80% lower emissions.
The design has been patented in Norway and internationally, and has received funding from Innovation Norway and private investors. It has been tank tested at Cranfield University in the UK, where it was reported that some initial scepticism quickly turned to enthusiasm for the principle.
Unsurprisingly, given the amount of windage on a PCTC ship, Mr Lade sees car transport as the initial market for the Vindskip design, with a capacity for up to 6,000 cars. He says he is talking to shipowners and yards, and believes that the first Vindskip could appear in as short a time as 3-4 years.