How Assumption and Miscommunication led to Collision

In daylight and good weather, a bulk carrier was in ballast and up-bound in a river. A down-bound tow vessel’s operator called the pilot of the bulk carrier to arrange a starboard-to-starboard meeting. This was as per local regulations that require the down-bound vessel, with the current astern and with the right of way, to contact the up-bound vessel and propose the manner of passage. The vessels agreed a starboard-to-starboard meeting and met without incident, but another down-bound tug was approaching and had not yet made meeting arrangements.

On the bulk carrier, the pilot assumed the second down-bound tug would require the same meeting as did the first, that is starboard-to-starboard. However, this was not the intention of the tug operator and he did not call the bulk carrier to make his intentions clear. For the next 85 seconds, the situation continued to develop in an ambiguous manner until the bulk carrier pilot called the tug to confirm what he thought would be a starboard-to-starboard meeting.

The tug operator was taken by surprise by this suggestion, as he had assumed a port-to-port meeting. In his opinion, the vessels were now too close to executing a starboard-to-starboard meeting safely. He initiated an emergency avoidance maneuver to starboard without informing the bulk carrier’s pilot. About 30 seconds later the two vessels collided.

Lessons Learned

• This is one more example of a vessel operator making an assumption about the intentions of another vessel operator which has led to a bad outcome. To reduce risk in this sort of situation, clear and unambiguous communication is essential.
• Follow the rules! In this case, the operator of the second tug should have called the up-bound bulk carrier and confirmed the manner of passage. Had he done so in a timely manner the collision would have been avoided.