MAIB: Anchor failures

The UK Marine Accident Investigation Branch (MAIB) has published Safety Bulletin 1/2021 relating to anchor failures.

What happened

The COVID-19 pandemic has seen many cruise vessels anchored off the UK’s south coast. During this period there were several anchor losses associated with the inclement weather over the autumn and winter and the use of the anchoring equipment beyond its intended design parameters.  The MAIB has been made aware of several marine incidents since October 2020 where cruise ship anchors or anchor cables have failed, often while trying to ride out named winter storms. One cruise ship lost both its anchors within a week.

The MAIB have identified a trend in the nature of anchoring equipment failures and have released this safety bulletin to the cruise industry to mitigate against further losses both in the short term and when the vessels return to normal operations.

Though this bulletin is about cruise ships, the principles of safe management and use of anchors are relevant to all IMCA members operating vessels.

MAIB recommendations

• Operational limits for anchoring must be sufficiently cautious to ensure weighing anchor is not left too late, risking overloading anchor equipment. If strong winds are forecast, proactive action should be taken to seek a more sheltered anchorage in good time or proceed to sea and ride out the weather;
• Do not wait until the anchor drags or until most of the anchor cable has been paid out before weighing anchor;
• Steps should be taken to minimize the wear on the anchoring equipment as far as possible. When the opportunity presents itself, the anchor in use should be rotated and the scope of cable varied on a regular basis to minimize single point loading. An appropriately experienced crew member should also carry out regular checks on the windlass brake condition and areas where the cable is in contact with the ship;
• While at anchor for signifcant periods, ensure all watchkeepers are confdent in the actions to be take in the event of dragging or losing an anchor and there is a contingency plan ready for implementation in the event of having to proceed to sea or re-anchor. Also, watchkeepers and senior officers must be aware of the reporting requirements to the coastal state in the event of losing an anchor so that mitigation measures can be put in place if required;
• Anchoring equipment should be assessed before returning back into normal service if it has seen greater use at extraordinary times.

Members may wish to refer to

• Near miss: uncontrolled movement of mooring chain
• Grounding of bulk carrier Kuzma Minin at Falmouth (MAIB)   
• Anchor drag near-miss incident