HMS London and the Amethyst Incident

In spring 1949 the modified Black Swan-class sloop Amethyst was trapped on the Yangtze by advancing Communist forces. She is often called a frigate because postwar usage increasingly applied that label to anti-submarine ships. London sailed upriver as a show of strength and an attempt to free her, but came under fire instead of intimidating the opposing forces. The cruiser replied with several hundred eight- and four-inch rounds even as multiple turrets were damaged. London withdrew to Hong Kong for repairs lasting into July and was relieved by Kenya the following month.