Own vessel was approaching Felixstowe from the North via Sunk TSS. The Ro-Pax ferry was approaching Felixstowe from the North via North Shipwash channel. I had plotted the Ro-Pax ferry on ARPA for at least 30 minutes, CPA was effectively zero. Visibility was very good, observed visually at 8nm. It was clearly a crossing situation with Ro-Pax ferry on my portside, green sidelight and fore and mainmast navigation lights clearly visible at a distance of 3nm. I called the Ro-Pax ferry to confirm his intention. His response was to advise that he was also proceeding to Felixstowe via North Shipwash. I pointed out to him that CPA was zero and asked what his intentions were. He stated that in his opinion I was overtaking him and should keep out of his way. I again advised it was not an overtaking situation and never was. Clearly a crossing situation and Ro-Pax ferry was the give way vessel. He asked if I wanted him to alter course 90 degrees to starboard or slow down. I replied that it was up to him to decide what to do to give way. At distance 2nm CPA was still zero called him again and asked him if he had reduced speed. He replied that it was taking time. He had clearly made no effort to slow down. At this point I told him to maintain his course and speed and I would alter course to port and further reduce my speed. This I did and passed astern of him. The master, third officer & helmsman were on the bridge with me.
Lessons Learned: Never rely on other vessel to obey collision regulations. He should have taken action as required by the collision regulations in ample time, before it became a close quarters situation.
In the majority of cases, an early reduction in speed can be as effective as an alteration of course in order to avoid a vessel approaching from abeam or near the beam Clearly in this report this did not happen. COLREGS Rule 17(a)(ii) states: The stand on vessel may take action to avoid collision by her manœuvre alone, as soon as it becomes apparent to her that the vessel required to keep out of the way is not taking appropriate action in compliance with these Rules.
The OOW of the stand on vessel took prudent and early action to avoid risk of collision.
CHIRP observed in a past study using a ship simulator to review P&I club reports on 24 collisions, 17 of these would have been avoided if there had been an early reduction in speed; the end result revealed the ship lost on average only 20 minutes delay in the ETA.
It was noted many of the larger (bulk carrier) ships are not able to quickly reduce speed easily without causing damage to the main engine through cracks to the liners and casing.