In this post, David McKie and Natalie Haefner, who both work at CMS and have a special interest in shipping and maritime matters, preview the decision awaited from the UK Supreme Court in the matter Evergreen Marine (UK) Limited v Nautical Challenge Ltd

On 5 and 6 October 2020, the UK Supreme Court heard the appeal in the matter of Evergreen Marine (UK) Ltd v Nautical Challenge Ltd. The appeal concerns a collision at sea on 11 February 2015 between the appellant’s vessel (“EVER SMART”) and the respondent’s vessel (“ALEXANDRA 1”) just outside the dredged entrance/exit channel to the port of Jebel Ali in the United Arab Emirates. This is the first collision liability case to be heard in the Supreme Court.

Collisions at sea are now relatively rare. When they do happen, it is usually the result of negligent navigation by each of the ships involved, in particular a failure to follow one or more of the customary rules of good navigation and seamanship codified into international law in the International Regulations for Preventing Collisions at Sea 1972 (the “Collision Regulations”).

Under English law, each ship has proportionate fault for a collision. Section 187 of the Merchant Shipping Act 1995 states:

Where, by the fault of two or more ships, damage or loss is caused to one or more of those ships, to their cargoes or freight, or to any property on board, the liability to make good the damage or loss shall be in proportion to the degree in which each ship was in fault. If, in any such case, having regard to all the circumstances, it is not possible to establish different degrees of fault, the liability shall be apportioned equally”.

Apportionment of fault for a collision depends upon an assessment of the blameworthiness and causative potency of each vessel for the collision, often judged by reference to the failure to comply with the Collision Regulations. The assessment is of the relative degree of responsibility of each vessel.

The main issue for the Supreme Court in this case is the interaction between the narrow channel rule (Rule 9) and the crossing rules (Rules 15-17). The appellant is seeking the Supreme Court to reconsider the approach of the courts below, which treated the crossing rule as inapplicable where one vessel is in a narrow channel and the other is approaching that channel, and held that the crossing rule applies only where a give-way vessel is on a steady course.


On 11 February 2015, EVER SMART, a laden container ship, owned by Evergreen Marine (UK) Ltd, collided with ALEXANDRA 1, a laden VLCC, owned by Nautical Challenge Ltd. ALEXANDRA 1 was inbound and EVER SMART was outbound. The collision took place at night but there was good visibility and clear skies. The damage suffered by ALEXANDRA 1 amounted to over US$ 32 million. The damage suffered by EVER SMART amounted to almost US$ 4 million. The parties could not agree the degree of proportionate fault.

The main dispute was whether Rule 9 or Rule 15 of the Collision Regulations applied in the circumstances.

Rule 9 – narrow channels 

  • A vessel proceeding along the course of a narrow channel or fairway is obliged to keep “as near to the outer limit of the channel or fairway which lies on her starboard side as is safe and practicable.”
  • Rule 9 also forbids vessels to cross a narrow channel or fairway “if such crossing impedes the passage of a vessel which can safely navigate only within such channel or fairway.”

 Rule 15 – crossing situation 

  • When two power-driven vessels are crossing so as to involve risk of collision, the vessel which has the other on her own starboard side shall keep out of the way and shall, if the circumstances of the case admit, avoid crossing ahead of the other vessel.”

Counsel for EVER SMART argued that Rule 15 applied, requiring ALEXANDRA 1, as the give-way vessel (travelling on an Easterly course with EVER SMART on her starboard side), to keep out of the way and avoid crossing ahead of EVER SMART.

Counsel for ALEXANDRA 1 disagreed, arguing that Rule 15 had no application in a situation where one vessel was navigating along a narrow channel and another vessel was navigating towards that channel with a view to entering it. They argued that in this situation, Rule 9 applied, which required EVER SMART to keep to the outer limit of the channel, and had she done so then the collision would have been avoided.

At first instance, Teare J held that the crossing rules did not apply. ALEXANDRA 1 was under a duty to navigate so that when she reached the channel she would be on the starboard side in accordance with Rule 9. ALEXANDRA 1 had acted reasonably and with good seamanship by approaching the channel and keeping close to her own side of the entrance whilst EVER SMART was still in the channel. Teare J also held that the crossing rules were inapplicable as ALEXANDRA 1 was not on a sufficiently constant direction or heading to be on a course – she was waiting to embark a pilot rather than herself being on a course at the relevant time.

EVER SMART was at fault as it breached Rule 9 by not keeping to the starboard side of the narrow channel. EVER SMART also breached Rules 5 and 7 of the Collision Regulations in failing to maintain a proper look out and making assumptions based on insufficient radar information, as well as proceeding at an excessive speed.

ALEXANDRA 1 was also at fault for not keeping a good lookout, leading to a misunderstanding whereby ALEXANDRA 1 believed EVER SMART was being told to go round the vessel when in actual fact this command was being directed to the local tug and not EVER SMART.

However, Teare J held that the excessive speed of EVER SMART “contributed far more to the damage resulting from the collision than the very much lower (and safe) speed of ALEXANDRA 1”. Accordingly, Teare J held that it “must follow that the causative potency of EVER SMART’s fault was greater than that of ALEXANDRA 1”. Fault was therefore apportioned 80:20.

EVER SMART appealed. Permission to appeal was granted in respect of the application of the Collision Regulations. However, permission to appeal against Teare J’s apportionment of liability was refused.

 The Court of Appeal Decision

The Court of Appeal dismissed the appeal.

The Court of Appeal held that both vessels, the give-way vessel included, must be on sufficiently defined courses for the crossing rules to apply, as that is the essence of the crossing rules.

Rule 15 did not apply in the circumstances. Counsel for EVER SMART argued that Teare J’s conclusion had not been stress-tested in a hypothetical scenario in which the inbound vessel was approaching from East-West as opposed to West-East and that, absent the application of Rule 15, there was subsequently no clarity as to priority, putting safety at risk. The Court of Appeal held that although ALEXANDRA 1 had been proceeding at a slow speed in a broadly east-south-easterly direction towards the entrance of the channel, her course varied between 84 and 112 degrees, and as such, could not be considered to have been “on a course” for the purposes of the crossing rules. Recognising that the Collision Regulations are practical rules and their primary objective is to prevent collisions at sea, the Court of Appeal was satisfied that Rule 9 governed the navigation of EVER SMART, and the approach of ALEXANDRA 1 was governed by principles of good seamanship, in addition to having regard to Rule 9. The fact that there was a risk of collision through convergence is not determinative of whether the crossing rules apply. The Court of Appeal took advice from Elder Brethren of \Trinity House Rear Admiral David Snelson and Captain Duncan Glass as nautical assessors in relation to the question of ‘good seamanship’. They advised that in an East-West scenario, a prudent mariner in an outbound vessel would keep a look out, comply with Rule 9 and proceed at a safe speed. The Court of Appeal accepted this advice, and although it was not strictly required to determine the applicability of the crossing rules in an East-West scenario, the advice did not undermine the first instance judgment on the actual West-East encounter.

For the purposes of assessing liability, both the relative culpability and causative potency must be assessed, and this is well established in law. Counsel for EVER SMART argued that Teare J was wrong in singling out and “double-counting” excessive speed in relation to causative potency (they argued he did so once in relation to the fact that the collision occurred and secondly with regard to the damage sustained). In contrast, ALEXANDRA 1 argued that Teare J had made a broad qualitative judgment, as he was entitled to do.

The Court of Appeal concluded that both the culpability and the causative potency of the faults are relevant to the apportionment of liability. Excessive speed is a primary example of a fault likely to contribute to the extent and severity of the damage suffered. Causative potency has two aspects – the first relates to the extent to which the fault contributed to the fact the collision occurred; and the second is the extent to which the fault contributed to the damage or loss resulting from the collision. This does not amount to “double-counting” but is separate counting of two different (and cumulative) aspects of the same fault.


Collision cases rarely reach the level of the Supreme Court – the last was a House of Lords decision in 1976.  It will be interesting to see what approach the Supreme Court takes on this issue, potentially with the benefit of advice from Elder Brethren as Nautical Assessors.

A proper understanding of the interaction between different rules within the Collision Regulations remains important from a practical perspective and a legal one. This is particularly so for the “crossing rules”, the application of which seems to create most difficulties for mariners in practice.  It is hoped that the judgment will bring practical guidance for mariners and some legal clarity to the interaction between rules in the Collision Regulations.

The concepts of causative potency and the parties’ relative blameworthiness are becoming more common. The approach taken in admiralty cases may therefore have wider relevance to assessment of contributory negligence generally.