Regular columnist Simon Tatham tackles the legal conclusion from the English Supreme Court ruling for vessels crossing at the entrance to narrow channels
Let us assume your tug is leaving port, outbound in a narrow channel a nautical mile or two from the exit, making 8 knots. You are complying with IMO’s collision regulations (COLREGS) narrow channel rule 9(a) and are sticking to the starboard side of the channel. You, however, observe a vessel to starboard moving very slowly but shaping to make a course across the entrance.
It is clear that its intention is to pick up a pilot and enter the channel and that it will have to turn to port to do so, to line up on her starboard side of the channel. Its bearing is steady.
Do the “crossing rules” (rules 15-17 of COLREGS) apply, making you give way to the vessel, or does the narrow channel rule, requiring you to stay on the starboard side of the channel, override that? What should you do?
The English Supreme Court, on appeal from the Admiralty Court in London, has now grappled with the tension between the two rules.
The collision in question occurred in February 2015 between UK-registered large container vessel Ever Smart and Republic of the Marshall Islands-flagged very large crude carrier (VLCC) Alexandra 1 in the pilot boarding area, just outside the exit of the dredged narrow channel to Jebel Ali, United Arab Emirates.
Alexandra 1 was inbound and awaiting the pilot transferring across from Ever Smart before entering the channel.
The Supreme Court has produced a detailed judgement referring to authorities going back to 1886, long before any uniform version of the COLREGS applied internationally.
The earlier decisions concerned collision cases in and around various narrow channels in the approaches from Bristol to Buenos Aires.
Two issues fell to be decided. The Supreme Court held that the crossing rules are overridden only when the approaching vessel is shaping to enter the channel, adjusting its course so as to reach the entrance on the starboard side of it, on its final approach.
That can be determined from the vessel leaving the channel by visual (or radar) observation of the approaching vessel’s course and speed.
The Supreme Court also held if two vessels are crossing so as to involve the risk of collision, the engagement of the crossing rules is not dependent upon the give-way vessel being on a steady course.
If it is reasonably apparent to those navigating the two vessels that they are approaching each other on a steady bearing, then they are indeed crossing, so as to involve a risk of collision, even if the give-way vessel is on an erratic course.
Rules for the avoidance of collision were first adopted by international convention in the 19th century. Since that time, the Admiralty Court in London has been tasked with interpreting and applying them to apportion liability in collision cases before it. These are typically 80:20 or two thirds, one third or 60:40 or 50:50 according to the degree of fault.
Fault is measured by the causative degree to which either ship adhered or not to the COLREGS. It is no simple task to extract precise guidance for navigators from a 60-page court judgment, but I would put it briefly as follows:
What then if your tug is towing a vessel and constrained in its ability to manoeuvre? How that alters its duties and those of an oncoming vessel in a collision situation is for another day.
COLREGS - IMO Convention on the International Regulations for Preventing Collisions at Sea