Are DP trials to be associated with non-productive time?

The aims of an annual dynamic positioning (DP) trials programme, as per IMCA M 190, are to:

• Demonstrate the DP system is fully functional, performing as intended with full power and thrust availability.
• Verify the level of redundancy established by the failure mode effects analysis (FMEA).
• Verify the effectiveness of essential protective functions and alarms.
• Verify the failure modes and effects of any modifications or upgrades are fully understood and incorporated into the FMEA and operational procedures.
• Meet the requirements of the classification society for annual survey.
• Be an effective tool for verifying, updating and generally managing the FMEA, thereby avoiding the need to redo the FMEA.

From the point of view of a client’s marine department, conducting DP trials will also give several major benefits.

DP systems are complex arrangements that can appear to have a life of their own. Proper annual DP trials witnessed by a competent third party (versus inhouse trials) will perpetuate and refine the process triggered with the initial DP FMEA study and proving trials of the vessel. The professional competency and independence of the third party will ensure continuous scrutiny of the entire system and progressively render it even more reliable through time by discovering new failure processes and some that remained initially undetected.

If the pre-assessment documentation analysis of the vessel can confirm the presence of a robust DP assurance process combining:

• An exhaustive initial FMEA study including analysis of failure modes and effects of systems, subsystems and individual equipment and proving trials report issued by a competent third party rather than by the shipyard.
• Consecutive annual DP trials, witnessed by a third party, aimed to prove that ‘Performance – Protection – Detection’ are still present, where required in the system, combined with close-out reports dealing with findings and recommendations.
• A five-yearly updated FMEA study including an overall test of the entire DP system corresponding to the vessel five-yearly class cycle.

Then analysis of the documents alone will automatically build confidence even before visiting the vessel by proving the entire assurance process is well integrated and care has been taken to demonstrate the vessel is able, through time, to still fulfill its intended industrial mission.

Unfortunately, many industry actors, including clients, see DP trials as non-productive time. Lack of acknowledgment of the entire DP assurance process coupled with the financial burden, including loss of day rate, that trials could bring have resulted in attempts to modify the structure and content of the trials process.

Consequently, often, DP trials will be reduced to an ‘empty box’, and semantics used to reduce it to its simplest form. Examples of such altered trials programmes can include:

• A shortlist of tests required for endorsement of Class or FSVAD delivered in lieu of annual trials and presented as being the only ones to be considered mandatory. This results in an inconsistent trial of intent to distinguish requirements and guidelines with regard to industry operational procedures and best practices. Furthermore, class and flag will guarantee compliance to IMO, mainly for safety of life and protection of the environment, but demonstrating the ability of the vessel to efficiently perform its intended industrial mission remains out of their framework.
• So-called rolling DP trials programmes suppressing the opportunity to have an overall test of the entire DP system performed every five years and reducing the annual trials programme to five successive one-fifths of a complete test – worryingly leaving each piece of equipment tested only once over a five-year period.

Even with faster evolving technologies, incidents still occur, serving as a constant reminder that risks remain present and that incident consequences can be catastrophic. To maintain safety of operations, commitments made should not suffer any kind of deterioration. With more laid-up DP vessels due to enter reactivation in the near future, the core purpose of the entire DP assurance process must be recalled and/or be reclarified for it to be considered again as a granted necessity.

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