201372 Loss of anchor

A few hours after leaving port the weather conditions deteriorated and the Master reduced speed, taking all necessary precautions for navigation in bad weather. Some time later the weather improved and the Master had the crew check the forecastle for any damage and the lashing and anchor stowage. All was found in order. The same day, the chief officer went forward on safety rounds and both anchors were once again found in the proper stowage position and secured. Later that day the weather turned bad again until the late morning of the next day. At that time the starboard side anchor was found missing while the chain, including the swivel and the end link, was still onboard.

What went wrong

A tongue type stopper is fitted such that the horizontal link of the chain rests on the tongue, thus taking the weight of anchor chain and the anchor, when the anchor is fully housed. It is believed the anchor, although lashed and secured with turnbuckle, was not fully resting on the chain stopper. This is supported by the fact that the anchor had been found loose some time earlier and the turnbuckle was re-tightened. If the anchor was fully housed and properly resting on the stopper, the lashing would not have been found loose. So the anchor, hanging slightly, was subject to heavy movements due to bad weather. This caused the pin of the D-shackle to be lost, resulting in the loss of anchor.

After the incident, corrective action was taken such that the anchor chain was properly resting on the stopper when the anchor was in the fully stowed position. Also, the locking pin on the D-shackle has been welded to avoid accidental release.

Editor’s note: While it is indeed important to have the anchor chain snug to the stopper, all other gear such as the turnbuckles should also be snugged up so as to hold the anchor fast against the anchor pocket.
 

Anchor as secured
  Missing starboard anchor
 
Comment from Mr Vilas Salukhe MNI, Kuala Lumpur, Malaysia published in February 2014 issue of Seaways

 

In my opinion the conclusions drawn need to be reviewed. The function of the chain chopper, whether of the tongue type or the guillotine type, serves to stop the chain as its name implies. This stopper is to be used when the vessel rides on the anchor. When anchored, the stopper is dropped on the chain and the locking pin is put in place.

When the wind force increases, the stopper transfers the force on the chain to the vessel’s hull. This force is not absorbed by the brake or the gear of the windlass. When the vessel is at sea, the anchor should be housed tight against the hull with a minimum of three points of contact between the anchor shank, flukes and the vessel’s hull. The anchor should then be secured with a devil’s claw (a two-pronged hook with threaded spindle and wheel) and /or a lashing wire and a turnbuckle that tensions the anchor chain up against the hull. The chain stopper does not play any part in securing the anchor tight against the hull, as it doesn’t produce any upward tension in the chain to secure the anchor. The loss of the anchor cited in this MARS report could be due to improper contact between the anchor and the hull of the vessel which can work the anchor loose in rough weather.