11 people drowned Thursday after a duck boat on Table Rock Lake in Missouri sank with 31 aboard. Rader said an off-duty sheriff's deputy was working security at the scene and helped rescue survivors. Recovery efforts continued after dark, with some passengers still unaccounted for. A dive team from Western Taney County was in the water and a team from the Missouri State Highway Patrol was on the way, as well. First responders from multiple agencies responded to the incident, initially reported as a “mass casualty incident” involving a "tourist type boat" on Table Rock Lake near Branson. Duck boats are WWII-era amphibious trucks still widely used for land-and-water tours, but their age and growing tally of deadly accidents may soon consign them to museums. Following is video of the boat sinking, taken from a nearby restaurant or vessel by Jennie P.