Hong Kong-flagged cargo ship CF Crystal was the causal factor of the collision with the Iran-owned oil tanker Sanchi, 160 nautical miles off the coast of Shanghai, China, on January 6, said the head of the Iranian committee involved in the joint investigation of the disaster.
Speaking at a press conference at Iran's Ports and Maritime Organization on Saturday, Nader Pasandeh said, "The black boxes of both vessels have been examined and reveal that the CF Crystal changed course barely 15 minutes before the collision."
He added that "the alteration of CF Crystal's course prior to the collision resulted in the disaster."
CF Crystal's first officer has admitted in an interview that he had started to adjust the course with the intention to go back to their planned passage minutes before the collision.
"My vessel was deviated from the port of the planned passage at that time," he said.
--- Point of Contention
This is where the Chinese and Hong Kong representatives do not see eye to eye with the representatives of Iran, Panama and Bangladesh.
Pasandeh said the two sides have not reached "full understanding over the causal factor of the incident".
Causal factors are any behavior, omission or deficiency that if corrected, eliminated or avoided probably would have prevented the fatality.
China and Hong Kong are of the opinion that "according to COLREGS [the International Regulations for Preventing Collisions at Sea], the two vessels were in a crossing situation, in which Sanchi was the give-way vessel and CF CRYSTAL was the stand-on vessel."
They believe as a give-way vessel in a cross situation of Rule 15, Sanchi did not take actions as required, claiming it to be the main factor leading to the collision.
According to Pasandeh, human errors by the Chinese vessel have contributed to the disaster.
"The CF Crystal’s watch-keeping personnel had not noticed Sanchi’s presence up to the time of collision," he said.
Pasandeh said no mariner can believe that such a giant vessel, which is no further than three miles off, cannot be identified on the radar.
Investigations show that "AIS [Automatic Identification System] had been used on board the CF Crystal as the sole means of collision avoidance".
The senior official added that either the dysfunctional radar or the improper use of AIS as a navigational aid contributed to CF Crystal not identifying the surrounding vessels.
Moreover, the deciphered black boxes show that Sanchi had sent flashing signals to CF Crystal, which was not noticed by the freight ship.
--- Human Errors
Pasandeh said some naval regulations have been breached by both vessels.
According to the official, the analysis shows that neither of the vessels complied with the requirements of Rule 5 of the COLREGS to maintain a proper lookout by sight and hearing by all available means appropriate and failed to make a full appraisal of the situation and of the risk of collision.
"The vessels also did not fulfill the requirements of Rule 7 of the COLREGS to use all available means appropriate to the prevailing circumstances and conditions to determine if risk of collision exists," he said.
The Sanchi—which was sailing from Iran to South Korea, carrying 136,000 tons of condensate, an ultra-light crude—sank on January 14 after drifting ablaze for more than a week.
All the 30 Iranian and two Bangladeshi seafarers died in the accident. The other vessel, CF Crystal was damaged at a comparatively minor scale and all of its 21 Chinese crew were rescued.
