2.2 The crossing rule and the give-way/stand-on dichotomy:
Under rule 15, “[w]hen 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”. The vessel “which has the other on her own starboard side” is referred to as the give-way vessel. The give-way vessel has an active role in avoiding a collision, as she must take positive action in order to keep out of the way of the other vessel, i.e. the stand-on vessel. The duties of the give-way and stand-on vessels are governed respectively by rules 16 and 17.(1)Other rules also remain applicable, such as those found in Part B Section I of the COLREGS.Rule 16 directs the give-way vessel to, “as far as possible, take early and substantial action to keep well clear”, while the main duty under rule 17, found in paragraph (a)(i), requires the other vessel to “keep her course and speed.”
Since the vessel Alexandra I had the Ever Smart on her starboard bow, the Ever Smart contended that this was simply and purely a crossing encounter which called for the application of rules 15, 16 and 17 above. In other words, it was the Alexandra I’s duty to keep out of the way and in failing to do so, she was at fault for the collision. The UK supreme court agreed that indeed the crossing rule, rule 15, ought to have applied, instead of the keep-to-starboard requirement, rule 9(a).