Abstract

We fabricated miniature yachts whose bottoms are coated with different water contact angle-materials, and investigated on the direct correlation between the water contact angle and the sailing velocity. As a result, the sailing velocity increased with increasing in the water contact angle of the yacht bottom. We considered that the rough surface of the yacht bottom, coated with the dispersion containing super water-repellent silica nanoparticles, may decrease contact area with water, resulting in drag reduction and subsequently increasing the sailing velocity. We also briefly reviewed recent patents (US0330340 (2010); US8258206 (2012); US6994045 (2006); US20120247383 (2012); CN200780042283 (2011); CN201110396837 (2011); CN201110167924 (2011); CN201010555247 (2011); WO2012015700 (2012)) on drag reduction by super water-repellent surfaces in this paper.

Keywords: Drag reduction, fractal structure, friction, super water-repellency, wettability, yacht.