sentences: "Isabel" also took part in the Nanking Incident on 24 March 1927, when shelling and threats of force procured the release of a large group of American and British prisoners held by Chinese nationalists in Nanking.She patrolled the 1,700 nautical miles (3,148 kilometers) of this dangerous river until 1928, when enough purpose-built river gunboats had arrived to serve in the Yangtze Patrol that she was no longer needed on the river.