Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.
On 25 May 2018, a 178 m general cargo ship was anchored at Anchorage B, at the Port of Bunbury. At 0800 Western Standard Time, the ship was dragging its anchor due to weather. The ship’s master requested permission from Southern Ports pilots to heave up the anchor and return to the anchorage. At 0808, the Bureau of Meteorology issued a severe weather warning for the Bunbury coast, with damaging winds and very rough seas forecast in the evening. At 1120, Southern Ports pilots also issued this warning, citing expected gale force winds, with ships at anchorage given permission to take their ships to sea, due to the poor holding ground. The ship was contacted by the Southern Ports pilots at midday by VHF radio, and warned the weather was expected to worsen. The ship’s master elected to remain at the anchorage.
At 1730, west-north-west winds had increased to over 34 knots and swell to 3.5 m and the ship began to drift. The ship’s master then requested permission from Southern Ports pilots to heave up the anchor and head to sea. The heavy pitch and roll of the ship resulted in the anchor chain being tensioned, preventing release of the anchor chain cable stopper bar. At 1738, the main engine was started and was used to manoeuvre the ship ahead, thereby releasing tension on the anchor chain. Shortly afterwards, the chief mate advised the master that the anchor chain had parted, resulting in loss of the anchor and 12 shackles of chain. Subsequent to the incident, the deputy harbour master advised that the ship’s anchor and chain had been located and was awaiting retrieval. At the time of the occurrence brief, the southern portion of Bunbury Anchorage B was unavailable for use due to the hazard posed by the detached anchor and chain.
Figure 1: Anchorage B at Port of Bunbury
Source: Australian Hydrographic Office, annotated by Australian Transport Safety Bureau (ATSB)
A lost anchor and chain can pose a hazard to other ships at anchorage through entanglement during anchoring. In addition, the loss of an anchor reduces the options of a ship to anchor safely. The ATSB investigation report into the Collision between Royal Pescadores and Da Heng Shan (308-MO-2014-003) is one such example, and is available from the ATSB website.
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.