AB. The International Marine Contractors Association. Guidance on. Failure Modes & Effects Analyses (FMEAs). IMCA M April AB. IMCA M, Guidelines for Failure Modes and Effects Analyses (FMEA). • IMCA M, FMEA Management. • IMO MSC Circular , Guidelines for Vessels with . IMCA M “Guidance on Failure Modes and Effects Analysis” o. IMCA M “ FMEA Management Guide”. 2 Unless expressly stated in this Guidance document.
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A DP2 pipelay vessel was set up on auto DP engaged in pipelay operations, inside the m zone of a fixed platform. The DP design concept of the vessel was such that there were two redundant groups that could only operate as a common system with bus tiebreakers closed. The vessel was ikca up with power generation and thruster supplies equally distributed across each redundant group as shown in the below example.
The weather was typical for the area: The engineer on watch noticed a developing load imbalance across the online imcx.
DG1 and 3 dropped load quite rapidly, leading to them both being tripped ijca reverse power protection, leaving only DG2 online. However, before DG4 was up to speed and synchronised, DG2 tripped on overload, leading to a blackout.
The DPO regained control of the vessel 35m away from the original position.
Case study – Load sharing imbalance caused loss of position
The pipe being laid remained connected to the vessel but was buckled. The decision was made to abandon the pipe and move the vessel to a safer location for detailed investigation. An investigation found that the DG2 governor had experienced a mechanical failure, leading to excessive fuel supplied to the engine. The generator protection and power management systems had imfa way of identifying the faulty machine although the PMS did generate load imbalance alarms prior to blackout.
The vessel had two redundant groups and the redundancy concept was such that they could only be operated as a common system bus ties closed. This case study demonstrates the importance of the FMEA. Therefore, it is vital that this analysis is m1166 up-to-date and current, considering all possible DP operating modes of the vessel. Although stating compliance with a variety of IMCA guidance, this well-known failure mode had not been captured.
Season’s greetings to our members and industry colleagues. Case narrative A DP2 pipelay vessel was set up on auto DP engaged in pipelay operations, inside the m zone of a fixed platform. Lessons learned The failure modes and effects m166 did not consider all the potential operating modes. There was no clear statement regarding the critical activity mode of operation CAM for the DP systems configuration. Furthermore, the FMEA had not been revised imcz many years and therefore there had been no possibility to improve and ijca the analysis in light of industry lessons learned since original production.
Failures of this nature are well understood and have been well documented in IMCA and other industry guidance for many years.
Guidance on failure modes and effects analysis (FMEA) – IMCA
There were no specific operating guidelines for the operation. The DP operations manual was lacking in specific operations data.