The crew of the HMNZS Manawanui didn't realise autopilot was engaged as it crashed into a Samoan reef, a military Court of Inquiry has found.
New Zealand's worst peacetime maritime accident occurred in October when the ship sunk off the coast in bad weather, with all 75 crew making it to shore in a dangerous overnight evacuation.
Chief of Navy Rear Admiral Garin Golding ordered the probe, which found a "series of human errors" behind the $NZ147 million ($A133 million) ship's loss.