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Stern flaps: A cost-effective technological option for the Indian shipping industry

ABSTRACT Surface Combatants are highly dependent on fossil fuels for their propulsion. During the course of its voyage, these vessels experience considerable amounts of drag or resistance based on the operational environment and their hull form. Reduction of this drag would result in a corresponding reduction in fuel costs, exhaust emissions, and an increase in the vessel’s speed and range. The operational flexibility of the vessel is enhanced by an increase in the time between successive refuellings, as well as the distance over which the vessel can operate without the need for replenishment. Of the many energy saving devices, fitment of a stern flap on Surface combatants is a very popular cost-effective means for drag reduction. The U.S Navy has extensively installed stern flaps on their combatants and, through this experience, found that suitably designed stern flaps had reduced the power requirement of the vessel they were fitted on by about 4–19%, an amount that translates to significant fuel savings and reduction in emissions. This paper will discuss the concept of stern flaps, examine the benefits offered by this technology on U.S Naval platforms, and will present the scope of leveraging this technology in Indian Defence Shipbuilding and Ship repair which could lead to significant reductions in power and emissions without compromising the platform’s performance.