201116 Colregs violation (Rule 9)

Own vessel was arriving at a major Asian port by night and was three miles away from the pilot station. We were making nine knots on course 030¼. Suddenly, we observed a large outbound tanker crossing ahead at a small angle from our port to starboard, showing a fine green light. We presumed that she had just disembarked the pilot, though no information was given by the pilot station or VTS. Soon, the tanker called us on VHF and requested the routine port-to-port or 'red-to-red' passage. Due to the alignment of the narrow fairway, it was assumed that the outbound vessel would soon arrive at the course alteration waypoint, alter to starboard and steer the reciprocal of our course, and shape to pass on our port side.

When the tanker was 2.5 miles away, and despite limited sea room to starboard, we unilaterally made a broad alteration of course to 060¼ (30¼ to starboard) expecting the tanker to do likewise. But the tanker continued on her original heading and a close-quarters situation was quickly developing. With the distance having closed to about 1.5 miles, we sounded five short blasts, and also tried to alert the tanker by VHF and Aldis lamp. Eventually, acting under Rule 17 (Action by stand-on vessel), we altered more to starboard, coming to a heading of 100¼, leaving the fairway but exercising caution not to enter the charted shoal water. The tanker finally came to the correct heading and we safely passed at one cable distance on our port side.