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    IMCA publishes DP station-keeping incident data

    Publications // February 7, 2006

    The value of learning from other people’s experiences is obvious from a new publication from the International Marine Contractors Association (IMCA). 

    IMCA's  ‘Analysis of Station Keeping Incident Data 1994-2003’ is an analysis of IMCA dynamically positioned (DP) station keeping incident data over the 10-year period. The analysis extends the work that the trade association carries out on an annual basis to help determine trends and provide more detailed analysis on underlying causes.

    “Looking back over a period of ten years enables us to give a more detailed analysis of areas that are important and for which there is enough data to show some useful trends and contrasts than is possible in an annual publication,” explained Hugh Williams, the chief executive of IMCA. “This publication certainly enables us to emphasise the benefits of incident reporting and to come to some very definite conclusions.

    “The direct benefit of DP incident reporting, with all its implications, is that it keeps to the fore the acceptance that incidents do happen. This helps establish trends in incidents for discussion with vessel operators, equipment suppliers, training establishments and others to address particular issues. It also shows that catastrophic consequences from loss of position do not happen if the incidents are managed well. This is something of a sweeping statement, but it is reasonable to claim that if incidents were not in the open and discussed, management may at some point not give the solving of DP problems the resources they need and vendors would not have the motivation for improvement." 

    “Any organisation that promotes the exchange of technical and operational problems and their solutions is benefiting directly. The biggest direct benefit is always when an incident on one vessel has failure modes that directly apply to another and the transfer of this information prevents a re-occurrence of the incident because of the incident being reported. This is, of course, the most difficult to achieve, but it is nevertheless a worthwhile goal … our members are really learning from each other’s experiences. The results have helped keep the DP fleet operational, safe and acceptable to authorities by feeding into improvements in designs, procedures and training. There are indirect benefits too that are made clear in the new publication. Reporting of incidents and spreading knowledge and understanding throughout the DP industry is tremendously helpful to all.”

    The new report draws some fascinating conclusions:

    • For example the number of incidents caused by thrusters failure is high, especially when all the rules since the advent of DP are written to prevent the failure of a single thruster causing a loss of position.  However, a closer examination of this shows that none are from frequency drives and this has been a major advance for DP vessels.
    • Blackouts and partial blackouts have continued to occur even with advances in generators, switchboards and power management systems.  However the number of incidents and the number of vessels using DP has increased over the last ten years and this could be why the number of blackouts (full and partial) reported has increased, combined with the fact that very few DP vessels have been scrapped.  Nevertheless, there is a definite step change increase in the database between 1999 and 2000, perhaps due to receiving more reports overall that year.
    • A single thruster causing a loss of position dominates the percentage of incidents triggered by thrusters, even though DP rules and guidance have been written to prevent the failure of a single thruster causing a loss of position.  Thruster failures causing a loss of position are not decreasing
    • Cable/pipelay vessels are more likely to suffer from DP computer software triggers due to their DP software being designed more for holding position than track-follow

    “The document makes compelling reading for anyone involved with DP” said Williams. “We are extremely proud of what IMCA and its member companies have achieved. In sending out the publication we reminded members operating vessels that their 2005 incident reports are due – we want to publish our annual report as soon as possible to keep up the good work, and the constant learning curve and subsequent improvements.”

    Sections 1-2 of the publication provide readers with an overview setting the scene, characterised by a DP incident model shown on the first page; Sections 3-10 give more detailed analysis of areas that are important and for which there is enough data to show useful trends and contrasts; and the final sections are devoted to addressing the effectiveness of incident reporting and summarising the report’s conclusions

    Additional copies of the printed publication are available to members at £30 (plus 20 per cent for delivery outside Europe) and can be downloaded free of charge from the members-only section of the IMCA website at

    For non-members the cost per copy is £100 – these can be ordered from and from

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