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A raft passenger was spilled into a hydraulic* and recirculated in the water for 2 or 3 minutes before losing consciousness.

The passenger was released by the hydraulic only after he fell unconscious and stopped struggling. He had been on a commercial raft with six others, and had been trained in rafting safety commands before the trip started.
The hydraulic was at the top of the rapid, about 25 metres from the river bank. As the raft neared the feature, the guide intentionally angled the raft to approach side-on, to provide more excitement for the passengers.
As the raft rode into the hydraulic, its right pontoon was slowed suddenly by the upward flow of water. The jolt tumbled the passengers from the upstream side of the raft to the downstream side. The sudden shift in weight caused a downstream flip, spilling the passengers into the water.
A second raft, which was below the rapid, collected two of the swimming passengers. The guide of the flipped raft managed to re-right it, and recover four more passengers in a quiet eddy about 150 metres downstream of the hydraulic.
The guides quickly realised one passenger was missing, and spotted him floating toward them. He looked unconscious.
One guide waited in the eddy to see which way the current would take the passenger, and then set off to intercept him. He managed to snatch the unconscious passenger out of the water, and one of the other passengers on board performed rescue breathing.
This was successful, and the passenger started breathing again, while still in the raft. He was moved to the recovery position and rafted to the nearest exit track
Meanwhile, the second raft guide had signalled the emergency to the safety driver onshore, who had radioed the rafting base for help. The rescued passenger was picked up from the river bank by helicopter, and then driven by road ambulance to the nearest medical facility. He was later airlifted to hospital, where he made a full recovery.
*A hydraulic is formed when water in a river falls off a ledge, rock, log, or other object, picking up speed and rolling back on itself when it hits the water below, creating what paddlers call a “hole”. These are easily identified on a river by the white, foamy water that can be found just below a large ledge or rock.