A 4-year-old boy was left on Auckland's Queens Wharf watching his father hanging off a ferry after the gangway they were crossing broke and the boat started pulling away.
Carl Saunders says he was terrified that he would lose his grip and be sucked into the Fullers ferry's propellers and his son Kiel would lose his footing or jump in the water after him.
The 42-year-old yelled to strangers on the wharf to grab the boy as passengers helped him back on board. Maritime New Zealand may launch an investigation into the incident.
After visiting his father on Waiheke Island, Mr Saunders was on the 5.40pm boat back to the city on Tuesday night with Kiel, dog Elli and a family friend.
As passengers starting disembarking from the moored ferry, Kiel ran ahead on to the wharf but his father and friend were still on the gangway when the ferry started moving, and the plank ripped away from the wharf and was left hanging by its hinges.