Guam and Tutuila, Panay and Oahu, and the larger Luzon and Mindanao represented three sizes of American river gunboat. The smallest boats could reach the upper river throughout the year, while Panay's group had more limited access and the largest boats could go upriver only during high-water months. Greater size and crew capacity came at the cost of seasonal river access.
Notable Point · 40:47-41:30
Yangtze Patrol size and seasonal reach
Three sizes of American Yangtze gunboat show how displacement and draft determined whether a vessel could patrol the upper river year-round or only during high water.