On 21 January 1984, Cape Pillar, an Australian Government navigation aids support vessel, was engaged in bathymetric survey work at the eastern extremity of the Recherche Archipelago, southern Western Australia. The survey required the vessel to run parallel courses on headings of 150º and 330º, 3000m apart, between the 300m depth contour and the shoreline. A survey boat was utilised for the insg\hore portion of the survey, where it was too shallow for cape Pillar to proceed with safety.
At 1158, Cape Pillar commenced a survey run on the 150º heading, but as this survey line passed through Cooper Island, when the vessel was 1.1 miles from the island, course was altered to 060º, to take the vessel to the previous survey line. Shortly after the helm was put to starboard, to bring the vessel back to the 150º heading on the previous survey line, the echo sounder showed rapid shoaling of the seabed. The helm was put hard to port, but shortly afterwards Cape Pillar struck a submerged object. A few minutes later, three rock pinnacles were seen close by, about two metres below the surface.
The hull plating was ruptured in way of the cargo hold and adjacent double bottom tank, both of which flooded. The Master took the vessel to anchorage in Goose Island Bay, where portable salvage pumps were delivered to the vessel and a Navy damage control team boarded to provide assistance. The vessel was eventually able to proceed to Esperance and then onto Fremantle.
Conclusions
Cape Pillar struck an uncharted rock pinnacle.
The incident could have been avoided had an aerial reconnaissance been conducted beforehand and had the vessel been equipped with a forward scanning sonar.