Destroyer "Qingdao" (L) and frigate "Yantai" prepare to set sail at a port in Qingdao, east China's Shandong Province, Feb. 27, 2012. The 11th Chinese naval escort flotilla, consisting of destroyer "Qingdao", frigate "Yantai" and comprehensive supply ship "Huishanhu", departed from Qingdao on Monday for the escort mission in the Gulf of Aden and Somali waters to protect commercial ships from pirate attacks.