In this report, CHIRP received a message about two powered-driven vessels passing through a crossing situation. Specifically, the vessel (A) was proceeding westerly at 11kts with the other vessel (B) proceeding WNW at 11kts to the south and just forward of the beam.

Both of the ships immediately informed the Vessel Traffic Service, mentioning their actions, while they were in a ship to ship communication on VHF Channel 12. The reporter in this instance was the chief of the stand on vessel.

Credit: CHIRP

As the TCPA approached ten minutes with a CPA of less than 0.25nm, I contacted vessel (B) on Channel 12 and asked his intention - he suggested that I alter course to port. I told him I would not be doing that and intended to halt the conversation there and abide by the regulations. Vessel (B) then questioned why I wouldn’t alter to port and under which Rule, which concerned me slightly

... the reporter stated.

Moments later, the chief contacted the VTS and they advised him to make a bridge to bridge communication with the vessel (B). Then the vessel (A) limited its speed, avoiding the close quarters circumstances and risk of collision, giving the opportunity to vessel (B) to pass well ahead.

Rule 15 situations involving converging courses with a risk of collision seem too often to result in the give way vessel being reluctant to meet her obligations. This is something I regularly find working in the Dover Strait and English Channel

... the reporter added.

The reporter also stated that the non taking actions of the give way vessel in crossing situations, it is a rarely seen phenomenon, while he hopes that the publication of the incident will raise awareness of the issue and will give the matter great attention.

In light of this report, CHIRP comments:

  1. this was a classic converging vessel situation
  2. the encounter took place in daylight which added to the ambiguity of the situation. At night the cut off angles of navigation lights would have added clarity to interpreting if this was a crossing situation or an overtaking situation.
  3. vessel A interpreted the situation as crossing vessels governed by Rule 15
  4. it is possible that Vessel B construed it to be an overtaking situation governed by Rule 13(a)
  5. if the above points are correct, then both vessels by their own interpretation of the situation were the stand on vessel
  6. in the above report vessel A acted under Rule 17(a) (ii) and complied with Rule 17(c)
  7. whatever the case, as the vessels drew closer both would have been governed by Rule 17(a) (ii) and ultimately by Rule 17(b)
  8. whatever the situation Colregs should work, even if a vessel fails to comply with a rule or misinterprets a situation
  9. it is refreshing to note that the avoiding action taken in this case was a significant reduction in speed