RulesMaster

In daylight and clear weather, the fishing vessels Navegante and Teresa Maria collided when returning to their home port of Wheatley, Ontario, Canada.  Both were on automatic pilot and proceeding at full speed.  The Navegante was steering 010 degrees at 11 knots, slowly overtaking the Teresa Maria steering 000 degrees at 10 knots.  As the distance between the vessels diminished, neither vessel altered course or reduced speed.  When the vessels were within 15-25m apart and nearly abeam of each other, the Navegante suddenly veered to starboard, striking the port side of the Teresa Maria.  Who was at fault?  What rules apply?

The operator of the Teresa Maria saw that his vessel was being overtaken by the Navegante.  Upon determining that a close quarters situation was developing, he unsuccessfully attempted to communicate with the other vessel by VHF radio.  As required by rule 17 (action by stand-on vessel) part a, he kept his vessel to her original course and speed.  However, as the distance between the vessels decreased, the operator did not use sound signals to attract the attention of the overtaking vessel (rule 34), nor did he take action to avoid collision (rule 17 part b); the Teresa Maria remained on automatic pilot at 10 knots until after she was struck by the Navegante.

As the overtaking vessel, the Navegante was required to keep clear (rules 13 and 16).  The operator neither reduced speed nor altered course to avoid the development of a close-quarters situation.  The operator also failed to maintain an efficient radio watch. 

The vessels collided because the hydrodynamic interaction between two vessels proceeding at speed on nearly parallel courses and in close proximity caused the Navegante to sheer to starboard and collide with the Teresa Maria.  However, had either vessel taken appropriate action under the COLREGS, this interaction would never have occurred.

Source: Transportation Safety Board of Canada