The Simple Flat Plate (IHI L. V.-FIN) Achives 2 Percent Energy Savings
Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI) has fitted many full-hulled ships with the IHI Low Viscous Resistance Fin (L.V.- FIN). They all showed 2 to 3 percent energy savings and revealed no problem on the maneuverability and hull vibration in the sea trials.
The L.V.-FIN is a pair of simple flat triangular plates mounted on both sides of the stern hull forward of the propeller. The simple configuration reduces the manufacturing cost, and allows easy construction. It is able to install for the existing ships.
The viscous resistance of the full-hulled ship such as VLCCs and bulk carriers is over 90 percent of the total resistance. It consists of the frictional resistance and viscous pressure resistance caused by the vortical flow. The principle of energy saving is to reduce the viscous pressure resistance. By installing the Fin on the specific position, the Fin acts stabilizing the vortical flow around the stern hull and consequently reduces the viscous pressure resistance. The design procedure of the L.V.-FIN has already established based on the model tests and Computational fluid Dynamics (CFD).
The first 39,000-dwt bulk carrier with L.V.-FIN was delivered to The Kaisho Kaiun in 1995. The IHI has built over 30 sister ships during the last ten years, and has collected enough operational data for these ships. Comparison of the data showed the new ship with L.V.-FIN has proved excellent performance and has brought no harmful effect on maneuverability.
IHI has started the sale of design and consirucation of the L.V.-FIN for the existing ships in cooperation with Kobelco Marine Engineering Co., Ltd.
