Pilots cannot know everything about your vessel – lack of critical information on the pilot card, or provided in the master/pilot exchange can put the ship and its crew at risk, as Canada’s Transport Safety Board points out in its report on the grounding of the multipurpose cargo ship BBC Steinhoeft in the South Shore Canal of the St. Lawrence Seaway in March 2011.
Says the TSB report: ”
While Pilot No. 1 was aware of the possibility of a parallax error in navigation due to the offset position of the steering stand, he estimated that error to be about 0.5° and therefore did not compensate for this when giving his navigation orders to the helmsman. The investigation determined that this error was in fact 1.6°.
In navigational areas where tolerances are small, such as in this occurrence, accuracy is of the utmost importance. However, the determination of the parallax error induced by an offset bridge layout is not something that can be accomplished accurately without specific information. In this occurrence, Pilot No. 1 was not provided with such information, and therefore underestimated the extent of the parallax error.”