Senior students went to the rescue of an Otago Boys' High School rowing eight when their skiff was hit by a powerboat driven by their coach in Otago Harbour yesterday morning.
Three pupils were taken to hospital, one, a 12-year-old, with serious injuries thought to be caused by the boat's propeller.
Veteran rowing coach Fred Strachan, 91, had been driving the boat moments before the crash.
Police Inspector Lindsay Turner said the coach was speaking to the rowers through a loudhailer when the collision happened.
A father of one of the boys told the Otago Daily Times he saw the coach's boat "suddenly go out of control and just went over the boat and then slid back down". The still-moving propeller ripped up the side of the skiff - leaving visible marks and injuring one boy, while another injured boy jumped for safety into the water.