sentences:  During the tumultuous years that followed in China, "Isabel" served as a member of the patrol and as its flagship, charged with protecting American commerce from pirates.Based at Shanghai, "Isabel" spent the low-water period on the river at Hankow, returning to the coast in the summer.She and the other small gunboats of the U.S. Navy in China performed the arduous task of protecting American interests during numerous incidents and threats to American nationals.