Unmooring – Momentary Human Error – Wait for the splash… !


Whilst  unmooring,  the  forward  breast  lines were lowered by ships staff for release at the hook by the shore  linesmen.  The  officer  in  charge  (OIC),  assuming that the ropes had been released, gave the signal to the winchman to heave the  ropes  home.  The  winch operator commenced heaving. The OIC realized, simultaneously with advice relayed via  the  pilot  and master, that one of the mooring ropes had not released. He signalled to the winch operator to stop heaving, and    to slacken the rope. The rope was then released by the linesmen and the unmooring operations continued.  The pilot  issued  an  incident  report  which  was  followed  up by  the company.

Extracts from the Company Report:

The company conducted a thorough investigation and analysis of the incident, focussed upon human factors rather than blame. The salient points are as follows;

  • Mooring operations are covered by company’s Safety Management System, including work control manuals with specific reference to mooring. Procedures refer to appropriate industry publications, cover familiarization/ training, job hazard analysis and proper operation/ maintenance of equipment.
  • The mooring  team  consisted  of  the  OIC  and  four ratings. All personnel were experienced, considered  fully competent for the mooring operation, and had completed familiarization training prior to taking up any mooring duties. They were familiar with the terminal, and the communication practices between the linesmen and the mooring stations.
  • Prior to departure a tool box talk was given to all mooring party members and reported to the bridge. Similarly, the unmooring plan was agreed between master and pilot, then communicated to all.
  • Communications were supervised by the bridge. Standard practice is that the OIC communicates directly with the shore linesmen and vice versa using visual signals. There is no bridge intervention unless further clarification or guidance  is required.
  • The linesmen unhook the lines  once  slacked  by  the vessel. The OIC and the winch operator stand close to each other, so that effective verbal communication can be maintained. During critical verification times, the OIC stands in a location which ensures that both the shore and  ship’s  teams  can  be    Following  confirmation of release from the hooks, (by visual signal, which is acknowledged), the vessel heaves up the lines using the winches, initially  at  slow speed.
  • This was effectively implemented whilst releasing the headlines. With the breast lines however, and at the critical point of release, the OIC was not standing at the proper location, and was not able to verify that all lines were released. Instead an assumption was made that the lines had  been  released, based  upon  the  elapsed  time from the last visual contact with the Although unintentional, this was a violation of standard practice.  A further error was that the winch was operated at high speed, in contravention of standard practice. It was not clear why the winch operator acted that way.
  • No contributory causes of the error have been identified. Fatigue was determined not to be a factor


  • A review of the unmooring Job Hazard Analysis shows that there is no direct reference to the need to communicate with shore staff to prevent this kind of incident. (Procedural improvement indicated).
  • The OIC had become involved in the releasing/retrieval of  the  mooring  ropes  and  had  momentarily  assisted the crew instead of overseeing the operation. (Lack of situation  awareness).
  • The lines  of  communication,  for  handling  the  breast lines, were  insufficient  as  the  OIC  had  not  received  a signal  from  the  linesmen  ashore  to  verify  that  all  was clear and the mooring rope tails had been released from the hooks. Additionally, this had not been acknowledged, and  the  OIC  was  not  in  a  position  to  determine  that shore  linesmen  were  in  a  position  of  safety  away  from the hooks. (Lack of proper communication and improper position for the operation).
  • A human behavioural issue was identified in the unintentional risk  taken  by  using  time  elapsed  to infer critical information related to mooring operation. (Performance of a practice without risk appreciation).
  • Finally, the fact that the winch was operated at high speed at the initial stage of heaving up implies inadequate supervision. (Improper operation of equipment and lack of proper supervision).

Actions Taken:

  • The near miss analysis to be discussed with the terminal operator to improve existing mooring practices.
  • Just Culture process was applied with regard to the OIC, and will include a training session.
  • A Fleet Circular issued, sharing the lessons learnt and requesting a mooring operation evaluation review to be discussed on board and shared across the    The review to include a mooring operation hazard analysis   to ensure the lessons learnt from this near miss are incorporated, for use in future toolbox talks.
  • The lessons learned are to be included in Fleet Training Officer material for on-board training.

CHIRP Comment:

The Maritime Advisory Board emphasised that the person in charge should not get involved in handling ropes and should always maintain a full oversight of the operation. The company’s effort to investigate the human factors is refreshing – it is only by doing this that root causes will be properly addressed, as opposed to simply saying “Did not comply with the SMS!”.

Useful references – OCIMF Effective mooring, and the Nautical Institute Mooring and Anchoring Ships Volumes  1&2.


Report Ends