Harbourmasters have shut down Northport, Marsden Point, Port of Auckland and Port of Tauranga this weekend and are tying everything down in the face of the most powerful cyclone since Gabrielle. One oil tanker that was to have sailed for Tauranga on Saturday is the lightly laden Amasya; instead it’s remained tied up in the safety of Port Nelson. But two other tankers aren’t so lucky: Z Energy’s 75,000 deadweight tonne Hafnia Expedite and the 45,…