Transport Accident investigators will be poring over a ship that ran aground and was stranded on the rocks in Doubtful Sound on Wednesday evening.
The vessel, called the Fiordland Navigator, had 57 passengers and 10 crew onboard at the time.
All passengers were evacuated, and one had minor injuries.
The Transport Accident Investigation Commission says the boat's hull was breached and it took on water, but was re-floated later that night and returned to its berth at Deep Cove.
Chief investigator of accidents Naveen Kozhuppakalam spoke to Corin Dann.