Liability for collisions at sea arises in English law from the tort of negligence. The plaintiff must be able to establish the three elements of negligence: A duty of care owed by the defendant to the plaintiff. Breach of that duty. Resulting damage. In relation to maritime law purposes, the duty of care was defined in The Dundee as being: “a want of that attention and vigilance which is due to the security of other vessels that are navigating the same seas, and which, if so far neglected as to become, however unintentionally, the cause of damage of any extent to such other vessels, the maritime law considers as a dereliction of bounden duty, entitling the sufferer to reparation in damages”. There must be proved negligence causing or at least contributing to the collision. As with any situation within the tort of negligence, it is the plaintiff’s burden of proof to show such negligence. The judge’s role in determining the apportionment of blame is to examine the evidence with a view: to evaluating culpability; and to deducing its ‘causative potency’. In the summer of 1965 the motor vessel Andulo collided with the tanker Statute of Liberty in good visibility at night off Cape St. Vincent. It was argued on the Andulo’s behalf that the masthead and green light of the other ship were sighted bearing 20º on the port bow between 5 and 6 miles away. Five minutes later, the bearing narrowed to 10º. At about 7 cables length distance and when the other vessel’s green light was just starboard of the foremast, the Andulo altered course for Casablanca. The Statute of Liberty altered to starboard; whereupon Andulo altered to port and then hard-a-port resulting in the collision.