Dutch manufacturer Hull Vane has developed a patented hydrodynamic device designed to improve the performance and seakeeping of medium-speed vessels.
Originally developed by Dutch naval architect and TU Delft professor Peter van Oossanen for use on an America's Cup sailing yacht in the early 2000s, the device has since been adapted for more widespread use in the private, defence, offshore, and leisure sectors.
The Hull Vane device shares the general appearance of a conventional hydrofoil but has been marketed by the manufacturer as a "partial-hydrofoiling application," as it is not intended to lift the vessel out of the water. Instead, the device works by generating a forward-angled lift force just aft of the transom, which in turn lifts the stern but also propels the vessel forward.
From force measurements and simulations with CFD, it was determined that the device provides additional thrust when sailing in waves – a phenomenon known as the "pumping effect," as the ship is pumping the foil when sailing in waves.
The submerged wing also has a profound influence on the stern wave, and as with a bulbous bow, when a ship generates less waves, it has a lower resistance.
When the ship sails in waves, the partial hydrofoil dampens the pitching motions and therefore reduces the added resistance from sailing in waves while improving the comfort onboard. This makes the device ideal for installation on passenger vessels such as ferries, crewboats, and superyachts.
The device has been tested on a 52-metre offshore patrol vessel, which sailed at 15 knots before and after the installation.
Hull Vane said the measured difference in fuel consumption at 15 knots was 27 per cent, which also translates into lower CO2 emissions. Further, the ship becomes quieter and less visible to aircraft or other ships due to the reduced "bubble trail," making it suitable for maritime security applications especially when avoiding detection by hostile forces.
