The Transport Accident Investigation Commission's final preliminary report shows that KiwiRail failed to follow manufacturers advice about a critical joint in its cooling system on the interislander ferry Kaitaki.
The incident happened in late January when the Kaitaki lost power, leaving it drifting close to Wellington's south coast.
The report finds that one of the ships safety-critical rubber expansion joints ruptured and prevented the engines restarting, and that the joint was old and overdue for replacement.
RNZ reporter Kirsty Frame has just been at a briefing at the Commission