Question 1

What does an annual DP trial, as guided by IMCA SEL 019, primarily demonstrate?

Accepted Answer

That the DP system is fully functional and the vessel can maintain its Worst Case Failure (WCF) under the prevailing environmental conditions — it is an operational readiness check, not an FMEA re-verification The annual DP trial is an operational readiness verification — does the system work now? It tests thruster and reference system functionality, alarm systems, and demonstrates that the WCF can be managed. It is NOT a repeat of FMEA proving trials. IMCA SEL 019 (Guidance on DP Footprint Trials) and IMCA M252 both specify what the trial should cover.

Question 2

What is the purpose of a Failure Mode and Effects Analysis (FMEA) for a DP vessel, and who mandates it?

Accepted Answer

The FMEA is a class-required document that systematically analyses each identifiable failure within the DP system and proves, by showing which failures are tolerable without loss of position, that the vessel has the redundancy claimed for its class notation Classification societies (DNV, Lloyd's, Bureau Veritas, etc.) require an approved FMEA as part of the DP class notation process. It is the engineering document that demonstrates the redundancy architecture actually delivers what the class notation claims — for DP2, for example, proving that any single failure leaves sufficient redundant systems to maintain position.

Question 3

Who is responsible for commissioning a DP FMEA, and who approves it?

Accepted Answer

The shipowner/operator commissions the FMEA, prepared by a specialist firm; it is reviewed and approved by the classification society as part of DP class certification An FMEA is a specialist engineering document, typically prepared by the DP system manufacturer, a marine engineering consultancy, or the vessel's designers. It must be reviewed and stamped by the classification society before it forms part of the vessel's class certification. It is not a document the DPO or vessel crew can prepare themselves.