RedactedNarrative: Operator had been hosting a large gathering at his waterfront residence.  Operator took 8 adults and 2 youths for a ride on the lake.  The youths were given adult sized life jackets to wear.  The youths were riding up front outside the railing and dangling their feet into the water while the boat was underway.  One of the youths went completely under the center of the boat and was then struck by the propeller, re-surfacing out of the back of the boat without a life vest on.  Two adults from the boat jumped into the water as well as a woman from another vessel to assist getting the youth onto the boat and back to shore.  The youth sustained injury. Operator is being charged with negligent operation and improper size boat life saving device.