Extreme Unpredictability

31st January 2008

Extreme Unpredictability

Initial Report

Report Text:

During vessel’s transit in open waters following close quarter situation took place.

Visibility in area was good, sky partly clouded, gentle breeze and slight sea. All happened during hours of darkness.

I was the officer on watch while situation took place. My vessel “A” was proceeding on course 110 deg at speed approx 13.6 knots in the Western Approaches to the English Channel. Other engaged vessel “B” was proceeding parallel on the same course and speed, about 6 nm ahead, approximately twenty-five degrees on my port bow. General traffic situation was clear without any potential collision risks for both mentioned vessels in original situation.

Suddenly vessel “B” started altering fast her course to starboard side. The green navigational light of vessel “B” was visible – it became apparent that vessel “B” intended to cross my course ahead of me at about 1.2nm and with an unstable CPA of about 0.8nnn. I was “stand on” vessel and as it was noted above, both vessels at this moment were not limited with manoeuvring by any others vessels, crafts or obstacles – so it was obvious that crossing ahead of me and with this CPA was simply unnecessary. I made VHF call identifying myself and my relative position to the vessel “B”. I brought attention of vessel’s “B” officer on watch to resulted situation and requested him to take preventive action and manoeuvre according to COLREG R.15. At first vessel’s “B” officer on watch had problems with assessment of situation resulted, but finally agreed to give way according to CDLREG R.15. At this moment the Captain arrived on bridge.

Vessel B hadn’t executed any actions distance decreased to 3 nm. i made another VHF call, and once again vessel’s B officer on watch assured me that he intends to alter his course to starboard and pass safely port to port and then astern of me. Finally vessel “B” passed ahead of me at about 0.8 nm without carrying out any coordinated actions to follow COLREG R. 15 and normal or good practice.

From this moment everything happened very quickly. When situation appeared to be safe – vessel “B” had crossed ahead of my bow and had a CPA of about 0.5nm when she was approximately ten degrees on my starboard side, green to green but still at close passing-by distance, suddenly she started altering course to starboard showing red nav light. Sent doubt signal (5 short flashes). Captain ordered rudder to starboard, so she crossed my bow second time at distance of approximately less than 0.5 nm ahead and finally both vessels passed port to port at full speed and excessive close distance of 0.25 nm (CPA). After clearing my port side the other vessel altered course more to starboard and set her course towards Falmouth.

If the course of my vessel wouldn’t be altered in critical moment – collision will be probable. Reduction of speed would have no effect due to drastically close distance. Alteration by my vessel to port was thought dangerous as the other vessel had already agreed to alter to starboard. An alteration of course to starboard would have resulted in an even closer quarters situation had the other vessel continued to stand on.

Thirty minutes later I received a VHF call from that vessel – asking if I am “cool down” already…

CHIRP Comment:

The OOW on ship A appears to have acted prudently in calling the Captain for what turned out to be a highly unpredictable situation.  Although the report does not explicitly state this, we assume that the Captain advised the OOW that he was taking over the con.  Ship A appears to have taken proper action under Rule 17 to avoid a collision.  We would however add that sound signals should be made in accordance with Rule 34.

We sent a disidentified copy of the report to the manager of ship B.  He has acknowledged it and advised that he is following it up.  However, at the time of going to press, we have not been advised of the outcome.

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