Pilotage Paradox
by Paul Drouin
The Cosco Busan accident, as with many others that have the same root cause, can be categorized into what I call the pilotage paradox. For on the one hand, we wish to confide the safety and con of the vessel to the pilot, yet on the other insist it is the crew and captain that are ultimately responsible and accountable for the safe conduct of the vessel.
In the seven minute interval between leaving the inner harbour and striking the bridge pylon, the pilot gave 13 helm orders without the slightest indication on the bridge of the Cosco Busan that anything was amiss. We know this because the National Transportation Safety Board (NTSB) has left an amazing amount of information on their public docket website, including transcripts of the bridge voice recordings.
Leaving berth 56 (Port of Oakland) and passing under the San Francisco-Oakland Bay Bridge is a relatively simple matter, even under blind pilotage conditions, as only two course changes bring you through the span. The Delta-Echo span of the bridge is wide, with a horizontal clearance of 673 meters, and is equipped with a RACON dead center of the span. For the Cosco Busan, winds were light and the vessel would be stemming the flood current as it passed under the bridge. This maneuver should not give an experienced 3rd Mate cause to sweat, much less an experienced pilot.
Under keel clearance was not great for the Cosco Busan, however, and as a consequence hydrodynamic forces on the hull caused by the flood tide would have been strong as the vessel’s sidebody came to obstruct the flow, which was setting at approximately 130° (T) near the bridge and anywhere up to 168° (T) further from the bridge. [Continue Reading →]
