The case arose out of two related collisions on 12 June 2014: (a) the plaintiffs’ vessel, the Arctic Bridge of the port of Malta and the Stena Provence of the port of Bermuda; and (b) the defendant’s vessel, the Tian E Zuo of the port of Hong Kong and the Stena Provence. As a result of the related collisions, the three named vessels sustained hull damage to varying extents. The plaintiffs and the defendant settled with the Stena Provence having accepted between themselves that the Stena Provence, a vessel at anchor, was not at fault at all for the related collisions. In the settlement, both the plaintiffs and the defendant assumed equal responsibility for the damage sustained by the Stena Provence. In this case, the plaintiffs contended that the defendant was wholly to blame for the related collisions whereas the defendant by counterclaim argued that the plaintiffs were responsible for the related collisions and must bear 100% blame.

The Arctic Bridge was a vessel underway when its port anchor or anchor chain entangled the port anchor or anchor chain of the Tian E Zuo, which was a vessel at anchor. The entanglement started an involuntary towage of the Tian E Zuo that culminated in the related collisions. The defendant contended that the involuntary towage effectively propelled the Tian E Zuo into contacting the Stena Provence twice. The plaintiffs’ case was founded on the negligence of the Tian E Zuo in permitting the vessel to drag its anchor initially and that the earlier anchor drag triggered a chain of events that culminated in the Arctic Bridge’s involvement in the related collisions.

Held: In apportioning liability, the court considers the relative blameworthiness and causative potency of the faults of each vessel. In relation to causative potency, the court is concerned with the causative impact each fault has on the eventual collision and loss. In terms of the relative blameworthiness, there were serious faults in respect of each vessel. Having regard to the causative potency and blameworthiness, both vessels are equally to blame and a fair apportionment is 50:50.