MarIus

5.3 The synergy between the give-way vessel’s duty under the crossing rule and the narrow channel rule:

While rule 9(a) only requires vessels to keep-to-starboard, under the crossing rule, the give-way vessel has at least three different possible options to consider, with two being preferable and more likely. The compatibility of each of these options with rule 9(a) deserves to be explored:

1. A starboard alteration – The duties under rule 9(a) and rule 15 turn out to be essentially one and the same for the give-way vessel in this case. An alteration to starboard will in most cases, with the exception of the one illustrated in Fig. 5.3., ensure that the crossing vessel is also keeping-to-starboard, which means that an alteration to starboard to keep out of the way of the stand-on does not lead to violation of rule 9(a). They are virtually the same action (Fig. 6.1(a), 6.1(b) and 6.1(c)).

   

   

   

   An alteration to starboard under the crossing rule does not appear all that different from one that is meant to ensure entry into the narrow channel, round a bend in a curved narrow channel or simply join the traffic on the correct side of the channel while following the keep-to-starboard requirement.

2. Speed reductions, stopping or reversing – As long as the give-way vessel stays on the starboard side, adjusting speed for example to wait for the stand-on vessel to pass before proceeding is not incompatible with rule 9(a) either. (Fig. 6.2(a), 6.2(b))

   

   

3. Porting – This option is the most likely to be problematic. First, in a narrow channel, an alteration to port would usually bring the give-way vessel across the bow of the stand-on vessel (Fig. 6.3(a) and 6.3(b)). Such action would be contradictory to the warning for the give-way vessel not to cross ahead of the bow of the stand-on vessel in rule 15. Secondly, it would entail abandoning the keep-to-starboard requirement of rule 9(a). Thirdly, it may also be in violation of the not-to-impede duty when the non-crossing vessel can safely navigate only within the narrow channel. The fact that the give-way vessel has access to two other means in this case which are better suited to avoiding the collision with the stand-on vessel render this third course of action quite unreasonable and potentially dangerous.

   

   

Where the crossing vessel is the give-way vessel under the narrow channel rule, the onus on the non-crossing vessel to identify whether the narrow channel rule or the crossing rule applies to the encounter is greatly diminished. If the non-crossing vessel (“NCV”) assumes a crossing situation, and the crossing vessel (“CV”) ends up not crossing, there are no negative consequences. The NCV’s duty is to simply keep-to-starboard and by doing the same, the CV ensures that they pass each other safely port-to-port. If the NCV’s assumption is correct and the crossing rule applies, her duty will be to maintain the course and speed which allows her to keep-to-starboard, while the CV has to keep out of the way. And as we have seen, with the exception of an alteration to port, actions taken by the CV to keep out of the way would be compatible with the narrow channel rule.

Therefore, the necessity for the non-crossing vessel to be able to determine the intentions of the other vessel is somewhat diminished, since the obligations of the stand-on vessel remain more or less unaffected regardless of which rule applies, and the give-way vessel can comply concurrently with the duties under both the crossing rule and the narrow channel rule. Simply put, if both vessels always apply both the crossing rule and the narrow channel rule in every equivocal crossing scenario, the need for predicting navigation would be greatly diminished. Compliance with the rules ought then to be encouraged.