What happened
At some time before 0530 on 8 May 2014, in adverse weather conditions at Fremantle anchorage, the securing pin worked free from Royal Pescadores’ port anchor chain cable stopper bar. The bar then opened and the windlass brake took the cable load. The brake did not hold and the cable ran out to its bitter end.

At about 0535, the securing arrangement of the bitter end gave way and the entire anchor cable was lost into the sea. With the anchor no longer holding it, the ship turned beam on to the wind and drifted towards Da Heng Shan anchored nearby.

At 0548, Royal Pescadores’ stern collided with the bow of the other ship. Shortly after 0550, Royal Pescadores’ main engine was started and it was manoeuvred clear. Both ships suffered minor collision damage.

What the ATSB found
The ATSB found that the poor condition of Royal Pescadores’ anchoring equipment was indicative of inadequate maintenance. As routine rounds to check the anchor cable had not been undertaken, no one detected the cable stopper’s securing pin as it worked free. Further, the ship’s main engine was not in an appropriate state of readiness for the adverse weather conditions forecast.

Although not contributing to the collision, Royal Pescadores’ anchor cable bitter end securing arrangement was not in accordance with the recognised and recommended design that would allow it to be slipped from outside the chain locker.

The investigation also identified that Fremantle vessel traffic service’s (VTS) precautionary measures for adverse weather conditions were triggered by Bureau of Meteorology (BoM) issued weather warnings. The VTS procedures contained no mechanism to trigger those measures in response to local wind speed conditions. As a result, there was a delay in implementing the measures in deteriorating weather conditions on 8 May.

What's been done as a result
Royal Pescadores’ manager advised the ATSB that it has taken safety action to improve the implementation of its shipboard safety management system (SMS). The action includes measures to improve crew familiarisation with the SMS, greater company oversight of planned shipboard maintenance, and highlighting the incident to ships in its fleet through a safety circular.

The ship’s managers also advised that all post-2013 built ships in its fleet are equipped with bitter end release arrangements in accordance with the recognised design recommendations. Further, the company intends to ensure this recommendation is applied to ships that it builds in the future.

Fremantle VTS has revised its weather-related procedures with the aim of ensuring that defined wind speed limits trigger precautionary measures. A range of new equipment and appropriate training for operators complements the revised procedures.

Safety message
Weather conditions associated with high wind speeds expose ships at anchor to the risk of dragging anchor and damage to anchoring equipment, and can result in grounding or collision. Therefore, it is imperative that the masters of ships take all necessary precautions to avoid such serious incidents. In waters covered by a vessel traffic service (VTS), the VTS can assist masters in managing those risks by providing weather and other relevant information.

Source: ATSB