Specification for DP capability plots

IMCA has become aware that some vessel owner/operators are undertaking a fixed percentage of an overall trials programme per year on the basis that over 5 years the full programme has been completed. This is not in compliance with IMO and IMCA guidelines Guidance for developing and conducting DP annual trials programmes (IMCA M 190). To assist with compliance, key definitions are provided below for reference.

DP Annual Trials Programme

This is the overall programme of tests to satisfy the annual survey requirements of Guidelines for vessels and units with dynamic positioning (IMO MSC/Circ. 1580). This programme may include Incremental and/or Rolling tests and/or tests that are evidenced by planned maintenance or survey records as defined below. It is essential all tests be identified within the programme so that it is clear what the test type is, and when the test will be undertaken. An example demonstrating this is given within IMCA M 190, appendix 1.

Annual DP Trial

A series of tests to verify the integrity of the DP system, conducted annually during a single period.

Incremental Tests

Tests performed to verify the integrity of the DP system, conducted over a defined period. Note that for the avoidance of doubt, this type of testing requires that an Independent Witness observes and confirms the test setup, methodology and accurately records the results detailing any resultant findings.

Rolling Tests

Tests on specified components or systems that have been identified as not being required annually but should be completed within a five-year period. Examples of such tests may include tests on non-critical redundancy, multiple failure modes of the same system. Examples would be a thruster variable speed drive with numerous points of failure or individual power system tests that automatically may be tested by wider group redundancy tests. In every case, it is expected that the failure modes associated with these tests are understood and have already been verified and validated within the FMEA proving trials programme. Rolling tests are therefore not simply a percentage sample of the overall DP annual trials programme.

Planned Maintenance or Survey Records in Lieu of Specific Annual Test Results

IMCA M 190 details that planned maintenance or survey records may be accepted in lieu of specific annual test results. Very specific conditions apply to this including the completion of a test sheet confirming what evidence exists to support the test.

Independent Witness

IMCA M 190 defines this as a sufficiently qualified and experienced individual removed from the day to day operational control of the vessel. IMCA recommends that this individual be accredited according to IMCA’s DP Practitioner Accreditation Scheme.

Digital Trials

IMCA is fully aware of the steps that DP system manufacturers are taking to develop and test digital solutions. IMCA will continue to review IMCA M 190 as required to ensure there is allowance for such solutions. It is essential that such solutions are fully robust in their approach and provide an equal or better outcome for DP annual trials programmes. Note that IMCA does not have an accepted definition for ‘Remote DP Trials’ which is a term that has been used in industry.  Members should ensure that DP annual trials programmes are completed in accordance with IMCA M 190, including the requirements for an Independent Witness.

Summary

All tests making up a DP annual trials programme must conform with the methodology set out in IMCA M 190 and highlighted in this information note. The DP trials programme must clearly identify which tests should be conducted under each of the above categories.

Originally issued with the following reference(s): IMCA M 07/20