The MV Rena was making 17 knots when she ploughed into the Astrolabe Reef in October 2011. On her way from Napier towards Tauranga carrying 1368 containers, 1700 tonnes of heavy fuel oil and 200 tonnes of marine diesel she impaled her bow on a pinnacle of rock. A few days later, fluids and lubricants seeping from her ruptured hull had formed a 5 km slick, and by the following day heavy fuel oil began to foul the beach at Mount Maunganui. The scene was set for a major economic and environmental catastrophe. Salvors worked in hideous conditions to stem the black tide. The stranding of the Rena has already prompted searching questions about New Zealand's ability to respond to maritime disasters. In Black Tide, John Julian looks at all the angles and asks what can be done to stop such a disaster happening again?