RedactedNarrative: Vessel one (V1) with one operator was towing a tube with three juvenile occupants around the unnamed lake behind their home. While making a sweeping left turn V1 came too close to a dock that extends out into the lake and the tube collided with the dock, ejecting all three occupants and causing serious injury. (broken bones and head injury); One tuber:Broken ankle and facial orbital bone; Second tuber:Fractures to upper and lower extremities. Closed head injury.