200835 Loss of both anchors with chain

One of our vessels lost both anchors and chain while attempting to anchor offshore in deep waters. Investigations indicated that correct anchoring procedures were not followed for such an operation.
With the echo sounder reading 90 metres, the port anchor was 'walked back' to 2.5 shackles and let go. The anchor along with the entire cable was lost when the bitter end parted under the shock load. Thereafter the starboard anchor was walked back to 4.5 shackles, and the process repeated with the same result. Unfortunately, in both incidents, the clear written procedures in the company's safety management system (SMS), below, were not followed, with serious operational and financial losses.

In the words of the SMS:
'"Extreme precautions are to be observed while dropping anchor in deep waters. The following guidelines are to be considered on such occasions in order to avoid loss of anchor:

Ensure that windlass brake linings are good and the bottom band stopper arrangement is properly adjusted.
Ensure while anchoring, the entire cable is walked out under power.
While lowering, vessel should be fully stopped with no speed over ground.
After laying about 1-2 shackles on sea bed, use very short bursts of engine not more than dead slow astern / ahead to range cable and pay out required length.
After the vessel is brought up, put guillotine bar and lock. Tighten brake full and then release gear.
Needless to state, the vessel should be wind / tide rode prior lowering anchor."

Editor's note: In general, company procedures for anchoring may consider being more specific when referring to 'deep water' and suggest a depth of about 40-50 m as a benchmark. It may also be useful to use the term 'anchoring' rather than 'drop anchor' to avoid misunderstanding.

FEEDBACK - November 2008

I appreciated this ‘special’ on anchoring incidents very much, as I think that a lot of incidents with anchors happen while anchoring (200835), while at anchor (200840) or while under way (200836). I must admit that I too have experienced several incidents, fortunately without any crew injuries or loss of anchors.

However, I am afraid that the SMS procedure mentioned in this case certainly does not apply in all cases, although in the case of MARS 200835 it might be very true that if the procedures were followed, this incident would have been prevented. This procedure might even contribute to loss of anchor in some circumstances.

Editor’s note: The safety management system is meant to provide, among other things, written procedures for emergency preparedness and response as well as routine operations. After ensuring that all applicable regulations are complied with, the company is the best judge on formulating the contents of its manuals. If new or revised regulations, industry guidelines, audit findings or experience require, procedures must be amended without delay, and their effectiveness monitored.